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MODULE OUTLINE
10.1 EPIDEMIOLOGICAL CHARACTERIZATION
10.1.1 Over-view
10.1.2 Incidence Trends
10.1.3 Causes
10.1.4 Disease Processes
10.1.5 Prevention & Control
10.2 RISK FACTORS
10.2.1 Nutrition:
10.2.2 Alcohol:
10.2.3 Tobacco
10.2.4 Physical Inactivity:
10.2.5 Environmental Factors:
10.3 CANCER
10.3.1 Incidence and Mortality
10.3.2 Cancer Sites
10.3.3 Risk Factors
10.3.4 Cancer Prevention
10.4 DISEASES BY ORGAN SYSTEM
A. Cardio-Vascular and Respiratory Disorders
B. Psychiatric and Neurological Disorders
C. Gastro-intestinal and Genito-Urinary Disorders
D. Traumatic and Musculo-skeletal Disorders
E. Other Disorders
10.5 DISEASES BY AGE GROUP
A. Intra-uterine Disorders
B. Maternal Disorders
B. Infant and Child Disorders
C. Adolescent Disorders
D. Disorders of the Elderly
UNIT 10.1
EPIDEMIOLOGICAL CHARACTERIZATION OF NON-COMMUNICABLE DISEASES
Learning Objectives
· Definition and characteristics of non-communicable disease
· Incidence trends
· Risk factors
· Prevention and control
Key Words and Terms
- Disease, Chronic Diseases
- Disease, Non-Communicable Disease
- Disease, Degenerative Disease
- Multiple Causes
- Prolonged Course
- Spontaneous Resolution
- Rare Complete Cure
- Non Transmissibility
- Specific Cause-Disease Relation
- Long Latency
- Transition, Ecological
- Transition, Demographic
- Transition, Epidemiologic
- Disease Burden
- Life Expectancy
- Risk Indicators
- Risk Factors
- Preventative Intervention
- Final Common Path
- Genetic Causes
- Environmental Causes
- Lifestyle
- Primary Prevention
- Secondary Prevention
- Tertiary Prevention
- Human behavior and lifestyle
- Years Of Potential Life Lost
- Economic Cost Of Disease
· Control
· Intervention
- Community Norms
- Enhancing Knowledge & Skills
- Screening & Follow-Up
UNIT OUTLINE
10.1.1 DEFINITIONS
A. Characteristics of Non-Communicable Diseases
B. Communicable vs. Non-Communicable Disease
10.1.2 INCIDENCE TRENDS
A. Data Limitations
B. Changing Patterns
C. Disease Burden
10.1.3 CAUSES
A. Unknown Causes
B. Preventive Action Based on Incomplete Knowledge
C. Multiple Causes
D. Life Style
10.1.4 DISEASE PROCESSES
A. Neoplasm
B. Inflammation
C. Degeneration
D. Metabolic and endocrine
E. Others
10.1.5 PREVENTION & CONTROL
A. Definition and Types of Prevention
B. Human Behavior and Life Style
C. Setting Preventive Priorities
D. Control
E. Intervention
10.1.1 DEFINITIONS
A. CHARACTERISTICS OF NON-COMMUNICABLE DISEASES
Chronic diseases (non-communicable, degenerative disease) are defined by the following characteristics: multiple causes, a prolonged course, lack of spontaneous resolution, rare complete cure, and non transmissibility from the victim to the susceptible. The prolonged course of these diseases depletes community and personal resources. The distinction between communicable & non-communicable is becoming blurred because diseases thought before to be non-communicable have now been found to have an infective etiology. Viruses have been implicated in neoplastic and chronic neurological diseases. The H. pylori bacterium has been implicated in chronic peptic ulceration.
B. COMMUNICABLE vs. NON-COMMUNICABLE DISEASE
Communicable diseases have a single defined necessary cause specific for the disease. Non communicable diseases are multi-causal, the causes are not known definitively, and the cause-disease relation is seldom specific. Communicable diseases result from a single exposure and cause acute disease after a short incubation period. Non communicable diseases have a long latency and chronic disease follows repeated exposures to the agent. A communicable disease is followed by acquired immunity but non communicable diseases are not. Diagnosis of a communicable disease is based on an agent-specific test. Diagnosis of a non-communicable disease is based on non-specific symptoms and signs.
10.1.2 INCIDENCE TRENDS
A. DATA LIMITATIONS
Data on chronic diseases is limited, incomplete, and inaccurate. This is more marked in developing countries where diagnostic and treatment facilities are inadequate. Reporting systems are not complete. Observed incidence trends may be due to differences in disease ascertainment. Epidemiologists therefore have to labor under the constraints of insufficient data in their analysis of disease occurrence and planning of intervention strategies.
B. CHANGING PATTERNS
Changing patterns in the incidence of non-communicable diseases have been observed over the past century. These are explained by ecological, demographic, and epidemiologic transition. There is a general increase in incidence explained by the relative decrease of infectious diseases as competing causes of death, an ageing and older population, a more complex society causing stress and depression, environmental pollution due to increased industrialization and disturbance of the natural eco-system, better detection and diagnostic characterization. The overall increase in incidence of non-communicable diseases is not uniform. Economically developed countries are experiencing a more rapid increase. Even within the same country, there are different trends in different population sub-groups.
C. DISEASE BURDEN
Non-communicable diseases are responsible for much disease burden. Complete elimination of all cancer would result in a gain of 2.5 years in life expectancy. Complete elimination of all IHD would result in a gain of 6 years. Elimination of infectious disease would result in a gain of 10 years. The average number of years of life lost due to all cancers is 15.3 years being distributed as follows: prostate cancer 9.3, lung cancer 14.9 years, female breast cancer 19.4 years, testicular cancer 36.4, and lethal childhood malignancies 68.8 years.
10.1.3 CAUSES
A. UNKNOWN CAUSES
The causes of most non-communicable diseases are not known definitively. Epidemiologists have identified putative risk indicators and risk factors. More studies are needed before definitive conclusions.
B. PREVENTIVE ACTION BASED ON INCOMPLETE KNOWLEDGE
Preventive action in public health does not have to wait for complete understanding of the causative factors. Preventative intervention is based on eliminating or modifying the suspected risk factors. In most cases definitive conclusions about causality emerge from the results of successful intervention. With the growth of molecular epidemiology, more will be learned about the risk factors and more effective interventions will become possible.
C. MULTIPLE CAUSES
Virtually all non-communicable diseases have multiple causes. The disease is the final path of interactions among genetic and environmental factors. Economic and personal factors also play their roles.
D. LIFE STYLE
Non-communicable diseases are closely associated with life style. The following are termed diseases of civilization because they are associated with the modern life style: appendicitis, gall stones, diverticulosis, ischemic heart disease, cancer of the colon, hiatus hernia, and varicose veins.
10.1.4 DESCRIPTION OF THE DISEASE PROCESS
A. NEOPLASIA:
PATHOLOGY
Much progress has been achieved in cancer biology in the past decade. We know a lot about carcinogenesis but our knowledge is still incomplete. Rapid advances in cell biology hold a lot of promise for the future. There is good undetstanding of the processes of cell neoplasia, anaplasia, heterotopia, atypism, polymorphism, metastasis, and the carcinogenic process that concerts a stem cell into a malignant cell. Pre-cancerous lesions like dysplasia precede malignant neoplastic change. These may stop and regress or may develop into frank malignancy. Neoplasms can be divided into benign and malignant. Benign neoplasms retain many features of the original cells; ie they are well differentiated. Their growth is slow and they do not invade local tissues or spread to distant sites. Malignant tumors on the other hand are rapidly growing, poorly differentiated, and are invasive. Malignant tumors are at different degrees of differentiation; the most undifferentiated are the most malignant and the most difficult to treat. The degree of malignancy can be understood as the degree of moving away from the normal. The neoplastic cells may be monoclonal or polyclonal. Monoclonal cells arise from one single cell that becomes neoplastic and proliferates. Poly-clonal malignancies arise from several initial malignant cells. Monoclonal malignancies thus show more homogeneity that polyclonal ones. The difference between monoclonal and polyclonal malignancy is important in understanding causality and response to treatment. The neoplastic process is essentially loss of control of cell growth; it is biological anarchy. The neoplastic cell replicates faster that a normal cell. It loses the important characteristic of contact inhibition and therefore does not stop growing when it comes in contact with adjacent cells. The neoplastic cells may invade local tissues or may spread, metastasize, to other parts of the body. The primary site of a neoplasm is the tissue where malignant change first occurs. The secondary site is where the malignancy metastasizes. Malignant proliferation continues in the secondary sites. Malignant tumors are of three categories: carcinomas, sarcomas, leukemias and lymphomas. Carcinomas are neoplasms of epithelial tissues, the endodermal and the ectodermal. More than 85% of malignant neoplasms are carcinomas (ie epithelial origin). This explains why the term cancer is used for all malignancies although it strictly refers to epithelial neoplasms only. Sarcomas are from mesodermal tissues. Leukemias and lymphomas are from cells of the bone marrow and the immune system. Symptoms and signs due to malignancy may be due to local pressure effects or may be systematic effects. Systemic effects may be due to pressure effects, destruction of vital organs such as the bone marrow and endocrine glands, or overwhelming the circulatory and excretory systems with many malignant cells. Some neoplasms produce systemic effects by secreting chemicals such as enzymes or hormones.
STAGING
A systematic staging system for each neoplasm is agreed on internationally to enable communication. It is called the TNM system because it is based on the Tumor bulk, Nodal involvement and existence of Metastasis. TNM staging is used to determine the type of treatment and also to forecast prognosis.
TUMOR MARKERS
Tumor markers are used in the diagnosis and assessment of prognosis for some malignancies. The commonest ones are oncofetal antigens, placental products, and isoenzymes. Alpha feto protein is an oncofetal antigen used in hepatocellular carcinoma. Placental alkaline phosphate is a placental product used in carcinoma of the ovary. Acid phosphatase is an isoenzymes used in carcinoma of the prostate.
ETIOLOGY
The etiology of cancer is multi-factorial and is poorly understood. There is a variable interaction between environmental and genetic factors. Some cancers are due to genetic factors independent of any environmental factors. Some cancers are due to a single autosomal dominant gene. Familial retinoblastoma is a good example. Some cancers are due to environmental factors with no involvement if any genetic factors for example lung cancer due to cigarette smoking, leukemia due to irradiation, and oral cancer due to alcohol consumption. A third group of cancers is due to the joint effect or interaction of genetic and environmental factors. These cancers are due to autosomal recessive genes. A fourth group of cancers is independent of both environmental and genetic factors and occurs by spontaneous mutation. The search for cancer determinants has involved both the epidemiological and experimental approaches. The following epidemiological observations give a clue to cancer causes: variation of cancer risk by socio-ethnic and geographical factors, change in cancer incidence in migrant groups, and change of incidence rate with time. The experimental approach involves testing putative carcinogens in animals and cultured cells. Epidemiological and laboratory studies suggest two established causes of cancer: irradiation and tobacco. Ultra-violet irradiation leads to basal cell carcinoma and melanoma. Exposure to ionizing radiation occurs medially, industrially, or in atomic bombing. Irradiation leads to malignancy by chromosomal damage. Irradiation is involved in the cancers of the breast, leukemia, and the thyroid. Tobacco in cigarettes leads to lung cancer. Studies suggest the following presumptive causes: chemicals, viruses, diet, alcohol, drugs, and genetic effects. Chemical carcinogens include polycyclic hydrocarbons e.g. in cigarettes, aromatic amines in aniline dyes, nitrosamines in food, toxins like aflatoxin, and alkylating agents used in cancer chemotherapy. RNA retroviruses are involved in HTLV and HIV related diseases. DNA viruses are involved in Burkitt's Lymhoma, Nasopharyngeal carcinoma, and hapato-cellular carcinoma. Evidence of dietary association with several cancers is strong but is not specific enough. Alcohol is involved in liver and esophageal cancers. Several cancers display a hereditary basis.
B. INFLAMMATION:
Inflammation may be infective or non-infective. Examples of infective inflammatory disease are: rheumatic heart disease due to delayed effects of the childhood beta hemolytic streptococcal throat infection; Chagga’s heart disease due to trypanosoma cruzi, and syphilitic heart disease.
Acute inflammation may turn into chronic inflammation. It is the chronic irritation of such inflammation that leads to several diseases. The common chronic inflammatory conditions are: chronic ulcers, chronic bronchitis, emphysema, and asthma. Chronic tropical ulcers turn into squamous cell carcinoma of the skin. Chronic bronchitis, emphysema, and asthma are chronic inflammatory conditions. There is no universally agreed definition of chronic bronchitis and emphysema. The two terms are used interchangeably. The natural history of emphysema/bronchitis starts with bronchial irritation or bronchial hypersensitivity due to occupational exposure to dusts (mineral and organic), chemicals, biological agents, and radiation. Smoking interacts synergistically with occupational exposure. Mucous hypersecretion and recurrent infection follow this. It ends as irreversible bronchial obstruction. Respiratory failure in bronchitis and emphysema is when the oxygen arterial pressure is low. There is no agreed definition of asthma. Child-hood onset asthma is outgrown by puberty. Little is known about adult-onset asthma.
C. DEGENERATION:
OVER VIEW
Degenerative changes occur as a function of time or longevity. The longer humans live the longer they are exposed to environmental insults that damage the body tissues. Some forms of damage are not due to external factors but arise spontaneously as metabolic or genetic disorders. Thus the statistical probability of cellular or tissue damage rises with age. At younger ages, any tissue damage can be repaired easily. With advancing age the reparative processes become impaired so that any damage once sustained is likely to turn into disease. The following are the commonest degenerative conditions: atherosclerosis leading to coronary heart disease (CHD), Alzheimer's disease, osteoporosis, and osteoarthritis.
ATHEROSCLEROSIS
Atherosclerosis occurs often with hypertension and their effects may be confounded. Atheroma affects arteries of medium or large size. It starts in childhood with fatty streaks that become localized fatty plaques in the 3rd decade of life and start bulging into the lumen of the blood vessel. This is followed by obstruction and narrowing. There are episodes of fissuring, rupture, embolization, thrombus formation, thrombus organization, and scarring. Atherosclerosis affects the abdominal aorta, the arteries of the neck, and arteries of the base of the brain, and coronary arteries. Atherosclerosis of the abdominal aorta causes abdominal aneurisms. Athesclerosis of the base of the brain causes stroke. Athesclerosis of the iliac and leg arteries cause peripheral vascular disease. Athesclerosis of the coronary arteries causes coronary artery disease. Coronary arteries are end arteries with limited collateral circulation. The terms coronary artery disease (CHD), ischemic heart disease (IHD), and atheromatous heart disease (ASHD) are used interchangeably. CHD is not a new disease. It is an epidemic that started in the 1920s. CHD, a progressive disorder due to obstruction of the coronary arteries by cholesterol-rich fibro-fatty deposits, causes fibrillation, and thrombosis leading to infarction. Manifestations of CHD are angina pectoris, chronic heart failure, and sudden death due to myocardial infarction. Angina arises on effort and is ischemic chest pain that results on increased cardiac work and thus higher oxygen demand. It is treatable medically by trinitrin, beta blockers, calcium blockers, long acting nitrates, and aspirin. It is treatable surgically by coronary artery bypass graft (CABG) and percutaneous coronary angioplasty (PTCA). Chronic ischemia may lead to impaired cardiac pump efficiency with limited exercise tolerance, which is known as chronic heart failure. An ischemic attack is preceded by prodromal symptoms of chest pain; dyspnea, tiredness, but they have low predictive value. It is treatable by defibrillation, aspirin, and anti-coagulants.
OSTEOPOROSIS
Osteoporosis is absolute decrease in the amount of skeletal bone. It is a personal health hazard especially in menopausal women because it leads to fractures. There is an ethnic variation. Whites are more affected than Asians. Blacks have an earlier peak bone density. Hormonal disturbances are usually involved: hyperthyroidism, hyper-parathyroidism, hyperactive corticolemia, and hypopituitarism. Low calcium intake, gastric or bowel resection, malabsorption, anorexia nervosa. Post-menopausal osteoporosis occurs 10-15 years after menopause. It is associated with crush fractures of the vertebrae, fracture of the lower fore arm, loosening of teeth. It is due to decreased calcium absorption because of hormonal imbalances. Senile osteoporosis causes widespread fractures due to the aging process.
D. METABOLIC AND ENDOCRINE
Many endocrine and metabolic disorders have been described in the past half-century. Diabetes mellitus is the most common and most important from the epidemiological perspective. DM was originally defined as the syndrome of polyuria, polyphagia, wasting, coma, and death. Later it was defined as chronic hyperglycemia. Two forms of this syndrome can be distinguished: insulin and non-insulin dependent diabetes mellitus. Insulin-dependent diabetes mellitus (IDDM) is the most severe form and occurs early in life. Non-insulin-dependent diabetes (NIDDM) occurs in obese and non-obese persons. Non-insulin dependent diabetes is mature-onset. Obesity plays a role in IDDM but may have no role in NIDDM. Among the complications of DM is diabetic retinopathy leading to blindness and cataracts. Renal complications. Arterial disease. Impaired glucose tolerance as measured by GTT and other types of hyperglycemia are found in non-diabetic disorders: malnutrition, pancreatic disease, hormonal influences, drug-induced, abnormal insulin receptors, gestational diabetes, and genetic syndromes. Metabolic disorders of carbohydrate, protein, and lipid metabolism are usually due to hereditary factors.
E. OTHERS
TRAUMA
Traumatic injury occurs in all human activities: at work, at home, and during recreation. The most serious traumatic injury is sustained in road traffic accidents (RTA). Injury of motor vehicle occupants is due to sudden deceleration. Industrial accidents are increasing. There are new forms of traumatic injury that are being described such as the injury to the hand tendons due to repetitive work.
PSYCHIATRIC DISORDERS
The organic basis of psychiatric disorders was suspected following the discovery of effective psychotropic medication. The organic mechanisms of many such disorders are becoming unraveled. There is however a core of psychiatric disorders for which an organic basis may not be found because they have to do with innate disturbances of the human psyche or nafs. DSM (diagnostic and statistical manual) of the American Psychiatric Association has specific but arbitrary criteria for classification of psychiatric disorders. It is backed up by a questionnaire that can be scored. Schizophrenia and depression are the commonest psychiatric disorders. Schizophrenia, besides being an economic burden and a source of family stress, leads to a marginalized life, poverty, homelessness, and higher risk of imprisonment. Depression has both somatic and psychological symptoms. It is an economic burden.
ORAL DISEASE
Oral diseases impair speech and eating in addition to causing disfigurement and pain. Dental caries are caused by acid-producing bacteria that lead to progressive decalcification of the dental enamel leaving a cavity called a dental cary
10.1.5 PREVENTION & CONTROL
A. DEFINITION AND TYPES OF PREVENTION
Prevention is defined as intervention before or early in disease. Primary prevention prevents occurrence. Secondary prevention shortens the duration of disease. Tertiary prevention prevents complications. Primary prevention is essentially is creating a pro-health anti-disease situation in the individual and the community. It includes general measures of adequate food supplies, education, employment, housing and other necessary community infrastructure and services. More specific measures include health promotion, health education, health care services, and protection from environmental hazards. At the individual level primary prevention includes proper nutrition, health knowledge, exercise, avoiding addictions to alcohol and drugs, and following all recommended safety measures such as seat belts. Secondary prevention at the community level consists of mass disease screening, case finding, and early appropriate medical care. The individual can undertake personal screening such as BSE, testicular examination, hemoccult test, pap smear, glaucoma tests, BP checks, and regular dental check-up. Screening for early detection and treatment is effective for some diseases and not others. Pap smear screening of women can prevent cervical cancer. A screening program consisting of breast examination and mammography can prevent breast cancer. Environment action is directed against water pollution, soil, and air pollution. Tertiary prevention consists of providing the necessary hospital facilities, medication compliance, exercise, and diet.
B. HUMAN BEHAVIOR and LIFE STYLE
Epidemiological knowledge available today is sufficient to make a major impact on many diseases. Persuasion of people to change their behavior is not enough. Consideration of using more coercive legislative measures violates the basic human rights of freedom of choice. The matter becomes more complicated when the rights of the individual have to be considered against the welfare of the general society. Most non-communicable diseases can be prevented by changes in human behavior or lifestyle. This is the Achilles' heel of epidemiology and public health because human behavior is very complex. It is difficult to fully understand what motivates humans to engage in some life-style activities and not others. It is even more difficult to understand how to change such behavior. In the US US
C. SETTING PREVENTIVE PRIORITIES
Resources available for disease prevention are limited. Some criteria must therefore be adopted to prioritize which diseases to start with in control. Generally three criteria are used: number of deaths from the disease, years of potential life lost, and the economic cost of the disease. The biggest causes of death in industrialized countries are: cardio-vascular disease, cancer, COPD, and accidents. The years of potential life lost, YPLL, is calculated by subtracting the age at death from 65. Economic data is needed to compute the economic cost of a disease. This includes lost earnings and money spent caring for the patient.
D. CONTROL
Control is defined as measures taken later in course of disease to reinforce preventive measures. The goals of chronic disease control are: Reduce incidence rate, Alleviate severity, Delay onset, Improve quality of remaining life, Change public attitude from inevitability to preventability, adopting healthy life-style.
E. INTERVENTION
Intervention against disease can be at the level of the individual or the community. The public health approach is directed at the community. The approaches used in intervention are primary prevention, early detection, treatment, and management of complications. The basic principles of intervention are: changing community norms, community involvement, formulating clear objectives, targeting specified populations, using multiple interventions that are locally relevant, and undertaking on-going evaluation with preparedness to change course if no results are seen. The strategies of disease control are modifying community norms, enhancing knowledge & skills, and screening & follow-up. The channels used in control programs are health-care system, schools, work sites, NGOs, and the media. The steps in the control process are review of health, demographic, economic, social, environmental conditions, definition of problems, definition of the target population, selection of the channel, choice of the strategy, preparing and piloting a plan, and then generalizing. Outstanding problems: No complete data, Application of biomedical knowledge, and Human behavior.
UNIT 10.2
RISK FACTORS
Learning Objectives
- Major Risk Factors of Non-Communicable Diseases
Key Words and Terms
- Under Nutrition
- Over Nutrition
- Qualitative Malnutrition
- Quantitative Malnutrition
- Malnutrition And Immune Deficiency
- Dietary Habits
- Hypertension
- Coronary Heart Disease
- Cholesterol
- Very Low Density Lipo-Proteins (Vldl)
- Atheromas
- Dietary Fiber
- Mycotoxins
- Aflatoxins
- Wernicke-Korsakoff Syndrome
- Mallory-Weiss Syndrome
- Fetal Alcohol Syndrome
- Ischemic Heart Disease
- Chronic Obstructive Lung Disease
- Passive Smoking
- Physical Inactivity:
- Sedentary Life-Style
UNIT OUTLINE
10.2.1 NUTRITION:
A. Under Nutrition and Over Nutrition
B. Qualitative and Quantitative Malnutrition
C. 2 Mechanisms of Nutritional Disease
D. Degenerative and Metabolic Disease
E. Neoplastic Disease
10.2.2. ALCOHOL:
A. Over-View
B. Psychological, Behavioral, and Neurological Disorders
C. Gastro-Intestinal, Cardiovascular, and Respiratory Disorders
D. Reproductive Disorders
E. Other Disorders
10.2.3 CIGARETTE
A. Over-View
B. Cardiovascular Disorders and Respiratory Disorders
C. Neoplastic Disorders
D. Other Disorders
E. Control of Cigarette Smoking
10.2.4 PHYSICAL INACTIVITY:
A. Over-View
B. Disorders Related to Physical Inactivity
C. Increasing Physical Activity
10.2.5 ENVIRONMENTAL FACTORS:
A. Over-View
B. Environmental Pollution
10.2.1 NUTRITION:
A. UNDER NUTIRION and OVER NUTRITION
There are two extremes of the mal-nutrition spectrum, under-nutrition and over-nutrition. Under-nutrition is more likely in the economically underdeveloped countries. Over-nutrition is more common in the economically developed and industrialized countries. There are however exceptions among population sub-groups. The elite of the developing countries has for example adopted the life-style of the industrialized countries and has similar disease of over-nutrition.
B. QUALITATIVE AND QUANTITATIVE MALNUTRITION
Malnutrition could be qualitative or quantitative. Qualitative malnutrition is specific malnutrition and involves selected micronutrients. Quantitative malnutrition is either excess total intake or reduced total intake. Qualitative under-nutrition occurs in developed countries usually due to life-style choices or food fads. Both qualitative and quantitative under-nutrition occurs in developing countries due to lack of sufficient nutrients. Gross mal-nutrition is seen in conditions of civil disturbance when food distribution networks break down.
C. 2 MECHANISMS OF NUTRITIONAL DISEASE
Nutritional disease can be described in two forms. Generally malnutrition is an underlying factor in all diseases due to its effect on the immune system. There are however diseases that are known to be specifically related to malnutrition: hypertension, coronary heart disease (CHD), diabetes mellitus, and various types of cancer. Change of dietary habits could eliminate a lot of disease. Dietary habits are influenced by culturally dependent food preferences, social eating patterns, availability of particular types of food, and food advertising.
D. DEGENERATIVE and METABOLIC DISEASE
Hypertension is associated with high sodium intake. CHD is associated with intake of saturated fat with low fiber leading to high levels of serum cholesterol and very low density lipo-proteins (VLDL) which eventually form atheromas and cause coronary arterial blockage. Diabetes mellitus is associated with a diet characterized by high fat and low fiber content. Gallstones are associated with high cholesterol, high sugar, and low fiber diets. Pancreatitis occurs in protein energy malnutrition (PEM). Dental caries are associated with prolonged contact of sugar with the teeth. Urinary calculi are associated with high phosphate diets.
E. NEOPLASTIC DISEASE
Esophageal cancer is associated with preservatives, dietary deficiency, alcohol, and mycotoxins. Stomach cancer is associated with dietary intake of nitrosamines and fats. Colon
10.2.2. ALCOHOL:
A. OVER-VIEW
Various human societies have been brewing and consuming various types of alcoholic drinks even before recorded history. Religions and cultural traditions have tried to stop or limit alcoholic drinks because of the social disruption caused by intoxication. The disease effects of alcohol were not known in detail until the recent past. Alcohol consumption is affected by knowledge of the health effects of alcohol, social and peer pressure, alcohol advertising, cost of alcoholic drinks, availability of alcoholic drinks, and legislative controls. Alcohol is associated with many psychological, behavioral, and physical disorders.
B. PSYCHOLOGICAL, BEHAVIORAL, and NEUROLOGICAL DISORDERS
The psychological and behavioral disorders are acute alcohol intoxication, acute alcohol poisoning, hangover, blackouts, and alcohol dependency. The Acute alcohol withdrawal syndrome manifests as delirium tremens, acute auditory hallucinosis, depression, attempted suicide, and suicide. The neurological disorders are epilepsy, peripheral neuropathy, cerebral atrophy, cerebellar atrophy, the Wernicke-Korsakoff syndrome, post traumatic neurological disease, and cerebrovascular disease.
C. GASTRO-INTESTINA, CARDIOVASCULAR, and RESPIRATORY DISORDERS
The gastrointestinal disorders are oropharyngeal carcinoma, Mallory-Weiss syndrome, esophageal varices, esophageal carcinoma, gastric and duodenal ulceration, atrophic gastritis, gastric carcinoma, disturbed bowel motility, intestinal malabsorption, colon carcinoma, pancreatitis, pancreatic carcinoma, alcoholic hepatitis, liver cirrhosis, and hapatocellular carcinoma.
The cardiovascular disorders are cardiac arrhythmias, alcoholic cardiomyopathy, cardiac beriberi, hypertension, and ischemic heart disease.
The respiratory disorders are obstructive sleep apnea, chronic obstructive lung disease, pneumonia, lung abscess, pulmonary tuberculosis, laryngeal carcinoma, and carcinoma of the lung.
D. REPRODUCTIVE DISORDERS
Reproductive and pregnancy-related disorders are depressed testicular function, depressed ovarian function, carcinoma of the breast, spontaneous abortion, perinatal mortality, low birth weight, impaired development (physical, mental and behavioral), congenital birth defects, fetal alcohol syndrome, pseudo-Cushing syndrome in breast-fed infants, and the alcohol withdrawal syndrome in the newborn. (Table 6-11 John M Last Public Health and Human Ecology 2nd edition Prentice Hall International, Inc.)
E. OTHER DISORDERS
Alcohol is associated with metabolic, endocrine, musculoskeletal disorders, hematological disorders, traumatic injuries, adverse drug interactions, and nutritional deficiencies. The metabolic and endocrine disorders are hypoglycemia, hyperglycemia, diabetes, gout, lactic acidosis, and deranged mineral metabolism.
10.2.3 CIGARETTE (Haroutine K Armenian and Sam Shapiro: Epidemiology and Health Services. OUP New York & Oxford
A. OVER-VIEW
Tobacco was introduced into Europe from the Americas US
B. CARDIOVASCULAR DISORDERS and RESPIRATORY DISORDERS
Smoking is a risk factor for coronary heart disease/ischemic heart disease and chronic obstructive lung disease. In the 1990s passive smoking was linked to cardiovascular disease. In the 1960s a dose-response relation between smoking and cardio-vascular disease was demonstrated. In the 1980s smoking, oral contraceptive use, and cardiovascular disease were found linked in women. In the 1960s smoking was associated with emphysema and respiratory disease. In the 1970s passive maternal smoking was linked to childhood asthma.
C. NEOPLASTIC DISORDERS
Cigarette smoking is a risk factor for cancer of the lung, cancer of the larynx, cancer of the oral cavity, cancer of the bladder. Smoking was related to lung cancer in the 1950s. In the 1970s passive smoking was linked to lung cancer. In the 1990s tobacco was classified as a carcinogen.
D. OTHER DISORDERS
In the 1970s maternal smoking was associated with low birth weight and other bad pregnancy outcomes (low birth weight, premature rupture of membranes, abruptio placenta). Cigarette smoking is associated with unintentional injury by fire.
E. CONTROL OF CIGARETTE SMOKING
Smoking behavior can be modified by: knowledge of the health risks, attitude to smoking, cigarette advertising, cost of cigarettes, peer influence, and legislation.
10.2.4 PHYSICAL INACTIVITY:
A. OVER-VIEW
Physical inactivity is a recent health problem that arose with the mechanization of many life and economic activities. Before the industrial revolution, the whole family worked with their own hands and for long hours; nobody was physically inactive. A sedentary life-style set in after the industrial revolution leading to the problem of physical inactivity that we are grappling with at the moment.
B. DISORDERS RELATED TO PHYSICAL INACTIVITY
Physical inactivity is related to the following diseases: hypertension, osteoporosis, and mental health.
C. INCREASING PHYSICAL ACTIVITY
Beliefs, motivation, self-discipline, availability of facilities for exercise, and peer support affect the level of physical activity undertaken by a person.
10.2.5 ENVIRONMENTAL FACTORS:
A. OVER-VIEW
The human habitat has an effect on the body physiology and affects what diseases may be contracted. Before the industrial revolution, humans had limited ability to disturb the natural order of their eco-system. With population increases and availability of machinery and technology to exploit natural resources, humans have caused severe dislocations in the eco-system.
B. ENVIRONMENTAL POLLUTION
Air, water, and soil pollution are today's manifestations of environmental degradation. They are responsible for a variety of diseases. All three types of pollution cause cancer. Air pollution causes chronic respiratory disease.
UNIT 10.3
CANCER
Learning Objectives
· Incidence of common cancers
- Risk Factors and Methods of Prevention for Common Cancers
Key Words and Key Terms
· Incidence Trends
· Cancer Survival
· Cancer Burden
· Cancer Sites
· Interaction between Heredity and Environment
· Spontaneous Malignancies
· Genetic Determinants
· Environmental Determinants
· Genetic Susceptibility
· Oncogenes
· Environmental Carcinogens
· DNA Damage
· Mutegenicity
· Chromosomal Damage
· Established Human Carcinogens
· Probable Human Carcinogens
· Possible Human Carcinogens
· Primary Prevention of Cancer
· Threshold Exposure
· Synergistic Relations among Co-Carcinogens.
· Modification of Behavior
UNIT OUTLINE
10.3.1 INCIDENCE AND MORTALITY
A. Over-View
B. Incidence Trends
C. Survival
D. Life Expectancy
E. International Variations
10.3.2 CANCER SITES
A. Lung Cancer
B. Breast Cancer
C. Cervical Cancer
D. Gastro-Intestinal Cancers
E. Other Cancers
10.3.3 RISK FACTORS
A. Interaction between Heredity and Environment
B. Investigation of Cancer Determinants
C. Established Environmental Determinants
D. Presumptive Environmental Carcinogens
10.3.4 CANCER PREVENTION
A. Primary Prevention of Cancer
B. Secondary Prevention of Cancer
C. Tertiary Prevention of Cancer
10.3.1 INCIDENCE AND MORTALITY
A. OVER-VIEW
Cancer is not a disease of one site. Almost all tissues of the body have neoplasms. Each of these has different biological characteristics which makes cancer not one disease but a collection of diseases.
B. INCIDENCE TRENDS
The incidence of cancers varies. Some are increasing whereas others are decreasing. Overall there is an increase in age-adjusted mortality due to cancer. Cancer incidence is increasing overall however for some specific sites there is an increase and there is a decrease for others. Stomach, uterus, colon, rectal, and ovarian cancer are decreasing. Lung, skin melanoma, kidney, liver, brain, prostate, breast, laryngeal, pancreatic cancer as well as Kaposi’s sarcoma are increasing.
C. SURVIVAL
Survival from cancer is improving overall. The largest improvements are in Hodgkin’s Disease, testicular cancer, bladder cancer, prostate cancer, melanoma, and non-Hodgkin’s Lymphoma. Little improvement in survival has been found in cancers of the liver, pancreas, esophagus, stomach, and lung.
D. LIFE EXPECTANCY
By taking 65 as a benchmark it is possible to compute the age-adjusted years of life lost due to cancer. This statistic is increasing in both developed and developing countries more so in the former. Elimination of all causes of cancer will however have a less impact on life expectancy at birth than IHD and infectious disease. The respective gains in life expectancy at birth would respectively be 2.5 years for cancer, 6 years for IHD, and 10 years for infectious disease.
E. INTERNATIONAL VARIATIONS
Cancer burden is distributed about equally between developed and developing countries but developing countries have three times as many people which indicates an overall higher risk in the developed countries. The major cancer sites of developed countries are the lung, the stomach, the breast, the colon, and the rectum. The main cancer sites in developing countries are: the cervix, the stomach, the mouth, the pharynx, and the esophagus. In terms of absolute numbers, non-melanotic skin cancer is the commonest malignancy in developed countries but is usually excluded from cancer statistics because it easily diagnosed, does not metastasize, is easy to cure, and is rarely reported by physicians.
10.3.2 CANCER SITES
A. LUNG CANCER
Lung cancer is a current public health epidemic. Males are affected more than females but the incidence in females is rising. Incidence rises with age.
B. BREAST CANCER
Breast cancer is mainly a disease of females. Incidence rises with age.
C. CERVICAL CANCER
Cervical cancer is more common in less developed countries. Its incidence rises with age.
D. GASTRO-INTESTINAL CANCERS
The incidence of colon cancer is falling in the US
ESOPHAGEAL CANCER
The incidence of esophageal cancer is high in Central Asia, the Far East , and the Transkein. There is an upward trend. Males are affected more than females.
STOMACH CANCER
The incidence of stomach cancer is higher in males but is declining.
LIVER CANCER
The incidence of liver cancer is high in Africa and the Far East but rare in Europe and USA US Africa is 20-30yr.
PANCREATIC CANCER
The incidence of pancreatic cancer is rising all over the world and increases with age. Africans and Maoris have high incidences.
E. OTHER CANCERS
Nasopharyngeal carcinima is high among the Chinese. Oral cancer occurs more often in less developed countries. It affects the elderly and males more.
10.3.3 RISK FACTORS
A. INTERACTION BETWEEN HEREDITY AND ENVIRONMENT
Cancer risk is determined by heritage or the environment or both. About 20-25% of malignancies are spontaneous. The following neoplasms are determined by heritage with no environmental effect at all: familial adenomatous polyposis, familial neurofibromatosis, Peutz-Jeghers Syndrome, familial retinoblastoma, and familial breast cancer. Environmental determinants are involved in the following malignancies: cigarette smoke in lung cancer, radiation in leukemia, and alcohol in oral cancer.
Genetic susceptibility enhances the effect of environmental agents for example the slow acetylation of aromatic amines in Caucasians makes them more susceptible to bladder cancer due to amines in dyes. The extensive debrisoquone metabolism and aryl carbon hydroxylase inducibility makes smokers more susceptible to lung cancer. It was thought that cancer was no an infectious disease. This idea is now changing. Schistoma hematobium infection is associated with bladder cancer. Schistosoma japonicum is associated with colo-rectal cancer. Cl. Sinensis is associated with cholangiocarcinoma. Hepatitis B virus is associated with hepatocellular carcinoma. Recently HPV has been associated with cervical cancer.
B. INVESTIGATION OF CANCER DETERMINANTS
Two approaches are employed in the investigation of cancer determinants: the epidemiological and the experimental approach. The epidemiological method gives non-specific and inconclusive evidence of environmental determinants based on geographical variation in incidence, change of risk on migration, and change of incidence with time. The experimental approach has described oncogenes. Environmental carcinogens act on oncogenes to produce proteins that either favor proliferation or that suppress tumor growth. Laboratory identification of carcinogens is based on long-term in vivo carcinogenicity tests in animals such as mice, rats, and hamsters. There are also available short in vitro tests for DNA damage, mutegenicity, and chromosomal damage. The International Agency for Research on Cancer based in Lyons
C. ESTABLISHED ENVIRONMENTAL DETERMINANTS
The established environmental determinants of cancer are: ultraviolet radiation, ionizing radiation, tobacco, alcohol, chemicals, and biological agents. The UV radiation with wave lengths 400-100 nm is classified into three categories. UV-A with wave length 400-320nm is responsible for skin tanning, skin pigmentation, and formation of cataracts. UV-B is responsible for vitamin D synthesis, erythematous reactions to sunlight, DNA damage, and skin cancer. The stratosphere absorbs 80% of UV-B. Non-melanotic skin cancer is expected to increase due to depletion of the ozone layer. Ionizing radiation is from background terrestrial or cosmic exposure, radioacive elements absorbed by the body, or exposure to artificial sources. Eighty percent of radiation exposure is from the background. Radon is 55% of background radiation. Tobacco smoking increases risk of various malignancies besides the lung. It is estimated that tobacco is responsible for 30% of cancers in developed countries. Mainstream and sidestream smoke have the same composition and therefore the same effect. Alcohol is associated with cancer of the pharynx, larynx, esophagus, and liver. IARC has so far identified 61 carcinogenic chemicals. The following biological agents are involved in cancer etiology. The liver fluke is associated with cholangiocarcinoma. Schistosoma hematobium is associated with bladder cancer. H. pylori is associated with stomach cancer. HBV and HCV are associated with liver carcinoma. HPV is associated with cervical carcinoma.
D. PRESUMPTIVE ENVIRONMENTAL CARCINOGENS
The presumptive environmental carcinogens such as chemical pollutants, electromagnetic fields, and diet. Water, air and food pollutants may have a role in carcinogenesis. Electromagnetic fields are suspected in leukemia and brain cancer. Aspergillus flavus is suspected in liver cancer and fat is suspected in colon cancer.
10.3.4 CANCER PREVENTION
A. PRIMARY PREVENTION OF CANCER
The strategy of primary prevention is to avoid exposure to known carcinogens. A conservative attitude is taken by avoiding even presumed carcinogens and assuming that there is no threshold exposure. The period of exposure is more important than the dose of the carcinogen. Synergistic relations among co-carcinogens should be identified and exploited because they are easier to attack than attacking the individual carcinogens. Selection of the method of exposure avoidance or minimization should consider financial constraints, technical feasibility, and human will to change behavior.
Modification of behavior can have an impact on cancer incidence. The percentage of all cancers preventable by various behavioral modifications is shown below: smoking cessation 30%, stopping alcohol 3%, reducing obesity <2%, not using hormones >1%, avoiding x-rays <1%, and avoiding workplace exposure <1%. Concerning exposures, we can assume a linear dose-response curve with no threshold. What matters is the length of exposure to the carcinogen. We can know that a carcinogen operates at a late stage in the carcinogenic process if there is an immediate fall in incidence with its removal. Cancers with 2 or more causative factors acting synergistically are easier to attack because there is intervention at several points. The future of cancer prevention may rely more on giving protective factors rather than on removal of carcinogens. Among the protective measures that are being studied are: use of retinoids, vitamin A, and anti-HBV immunization
B. SECONDARY PREVENTION OF CANCER
The following are general approaches to cancer management: surgery, chemotherapy, radiotherapy, hormonal therapy, and immunotherapy. Surgery is used to remove early lesions or decrease tumor bulk to facilitate chemotherapy of radiotherapy. Radiotherapy acts by destroying tumor DNA. In brachytherapy the source of the irradiation is in the tissues themselves. Chemotherapy uses various types of chemicals: alkylating, anti-metabolites, plant alkaloids, and antibiotics. Chemotherapeutic agents have both long-term and short-term complications. Hormone therapy acts by blocking the action of circulating hormones, reducing the level of circulating hormones, and by producing additional hormones. Bone marrow replacement and monoclonal antibodies are additional methods used
C. TERTIARY PREVENTION OF CANCER
In terminal cases, all what can be done is supportive care that comprises psychological support, pain relief, and nutritional support.
UNIT 10.4
DISEASES BY ORGAN SYSTEMS
Learning Objectives
- Incidence and Risk Factors
- Prevention
Key Words and Terms
UNIT OUTLINE
10.4.1 CARDIOVASCULAR AND RESPIRATORY DISORDERS
A. Over-View of Cardiovascular Disorders
B. Incidence and Mortality of Cardiovascular Disorders
C. Risk Factors of Cardiovascular Disorders
D. Prevention of Cardiovascular Disorders
E. Chronic Respiratory Disorders
10.4.2 PSYCHIATRIC AND NEUROLOGICAL DISORDERS
A. Psychiatric Disease
B. Abuse of Illegal Drugs
C. Alcohol Abuse
D. Mental Retardation
E. Neurological Disorders
10.4.3 GASTRO-INTESTINAL, GENITO-URINAL, METABOLIC, and ENDOCRINE DISORDERS
A. Oral Disorders
B. Gastro-Intestinal Disorders
C. Genito-Urinary Disorders
D. Metabolic Disorders
E. Endocrine Disorders
10.4.4 TRAUMATIC and MUSCULOSKELETAL DISORDERS
A. Traumatic Injury
B. Musculoskeletal Disorders
C. Physical Disability and Handicaps
10.4.5 CONNECTIVE TISSUE DISORDERS
A. Hematological Disorders
B. Leukemia and Lymphomas
C. Skin Disorders
10.4.1 CARDIOVASCULAR AND RESPIRATORY DISORDERS
A. OVER-VIEW OF CARDIOVASCULAR DISORDERS
There are three main categories of cardio-vascular disease: CHD, stroke, and rheumatic heart disease (in LDC). The other diseases of the heart are hypertensive heart disease, congenital heart disease, and infective heart disease. CHD, heart failure, and cardiac arrhythmias are the commonest causes of hospital admission. IHD, almost synonymous with CHD, is a leading cause of death mostly by myocardial infarction. Infarction has a high mortality with most patients dying before reaching hospital. Hypertension is defined as a systolic blood pressure >140 mm Hg and diastolic >90 mm Hg. Optimal blood pressure is systolic <120 and diastolic <80. Normal blood pressure is systolic 120-129 and diastolic 80-84. High normal blood pressure is systolic 130-139 and diastolic 85-89. Stage 1 (mild) hypertension is systolic 140-159 and diastolic 90-99. Stage 2 (moderate) hypertension is systolic 160-179 and diastolic 100-109. Stage 3 (severe) hypertension is systolic 180-209 and diastolic 110-119. Stage 4 (very severe) hypertension is systolic >210 and diastolic >120 (p. 230 James F Jekel et al Epidemiology, Biostatistics, and Preventive Medicine WB Saunders Company London). Hypertension is complicated by cerebral hemorrhage, heart failure, and renal failure. Heart failure is more often due to hypertension and is the commonest cause of death in hypertension. Excess mortality rises with the rise of blood pressure with no threshold. Cerebro-vascular disease, stroke, is the third commonest cause of death in DC and is increasing in LDC. The use of CT scans has increased the diagnosis of stroke. Comparison of incidence figures in different studies is not easy because methods of diagnosis and ascertainment of stroke differ. There are two types of stroke: cerebral infarction and cerebral hemorrhage. Stroke is the commonest cause of disability in the US
B. INCIDENCE and MORTALITY OF CARDIOVASCULAR DISORDERS
The incidence rate of cardiovascular disease is rising due to demographic transition to an older population that is at higher risk. In addition there is an age-specific increase in incidence rate due to the industrial/western lifestyle. CHD due to atherosclerosis accounts for 50% of cardiovascular disease. The most readily available statistics on CHD are mortality ones. Mortality due to CHD is rising by age but is lower in females than males. The difference between the genders decreases at the extremes of age. CHD is not an inevitable degenerative condition due to age; it has preventable environmental determinants.
Ischemic Heart disease (IHD/CHD) is more common in males than females with incoidence rising with age. Its incidence is high in the US and UK but low in Japan America
C. RISK FACTORS OF CARDIOVASCULAR DISORDERS
Several major studies of CHD risk factors have been undertaken: the Framingham Study starting in 1949, the Seven Countries’ Study, The Whitehall Study of 15,000 British Civil Servants, The British Regional Heart Study, the Scottish Heart Health Study, and the Multiple Risk Factor Intervention Trial (MRFIT) involving 300,000 subjects. The main risk factors are cigarette smoking, blood pressure, cholesterol and other lipids. The proportion of saturated fats in the diet determines the cholesterol level. HDL cholesterol is protective but LDL cholesterol increases risk. The role of TG is doubted but their level correlates with cholesterol levels. Excessive obesity, weight, and high BMI are crude estimators of body fat. Other factors involved in CHD risk are exercise, alcohol, diabetes, and SES. The relation between CHD and physical activity is difficult to establish because there is no standard way of assessing physical activity. The relation between CHD and alcohol is in dispute. Increase of diabetes is correlated with increase of CHD. The relation between CHD and SES is rather complex. It is true that CHD enters a community through the socially advantaged and leaves through the disadvantaged. On the global scale the poorest countries have the lowesr rates of CHD. The industrializing countries have the highest. The rate of CHD is falling in the established market economy countries. CHD mortality in industrialized countries is higher in the lower SES due to poorer medical care, a riskier life style (smoking, diet), psychosocial stress (job insecurity, job stress, and lack of control over destiny)
Essential hypertension has no known risk factors. Non essential hypertension has known treatable causes.
The risk factors of stroke are hypertension, smoking, alcohol, obesity, high serum cholesterol, and atrial fibrillation. The relation between alcohol and stroke is J shaped with low levels of alcohol intake being protective. High cholesterol leads to atherosclerosis and cerebral embolism/thrombosis. Atrial fibrillation is due to hypertension or atherosclerosis. ECG abnormalities, albuminuria, fundoscopic changes, and diabetes mellitus are risk indicators of stroke.
D. PREVENTION OF CARDIOVASCULAR DISORDERS
PRIMARY PREVENTION
Prevention of cardiovascular disease requires changes in these life-style and behavioral risk factors of cardio-vascular disease: cigarette smoking, physical inactivity, use of oral contraceptives, high fat diet leading to high serum cholesterol, high calorie diet leading to obesity and complications of diabetes mellitus, and high salt diet leading to hypertension. The primary prevention of stroke consists of management of hypertension, increase of physical activity, abstention from alcohol and smoking. The North Karelia Project showed that primary intervention against cardiovascular disease can be effective. The project was launched in 1972 with a base line survey. After 20 years of follow up, it was noticed that the following fell: smoking, cholesterol levels, and CHD mortality.
SECONDARY PREVENTION OF CARDIOVASCULAR DISEASE
The main measures of secondary prevention are screening for risk factors and management of blood pressure, coronary heart disease, and myocardial infarction. Regular blood pressure and lipid assessments are highly recommended. Total cholesterol is the sum of HDL, LDL, and VLDL/TG. HDL plays the useful role of scavenging other types of cholesterol. LDL is associated with high cardiovascular risk. VLDL is carried in the TG fraction and is associated with high cardiovascular risk. The level of VLDL is obtained by dividing the TG level by 5. The normal low risk values of the various serum lipids are as follows: Total cholesterol <200 mg/dl, HDL <50 mg/dl in men and <35 mg/dl in women, LDL <160 mg/dl, TG <150 mg/dl, total non HDL cholesterol <200 mg/dl, LDL/HDL ratio <3.5, and Total cholesterol /HDL ratio <6.9. Prudent diet and repeat of cholesterol determination in 5 years is recommended for tjhose with the desirable level of total cholesterol, <200 mg/dL. Lifestyle modification, diet modification, and annual cholesterol determination are recommended for those with borderline high risk levels, 200-239. If other risk factors are present lipid fractions are tested and treatment is based on the level of LPL cholesterol. Testing lipid fractions, diet and lifestyle modification and drug treatment are initiated for high risk levels, >= 240. Drugs can be used to treat lipid anomalies. Lovastatin is used to lower liver cholesterol synthesis. Cholestyramine and colestipol are bile acid sequestrants. Gemfibrozil and fenofibrate are used to break down VLDL. The mechanism of action of niacin is not known. Drugs and surgery are both used either singly or in combination in CHD management. The drugs that are often used are aspirin, nitrites, beta-blocking drugs, calcium antagonists, and antithrombotic drugs, anticoagulant drugs, and ACE inhibitors. Two surgical procedures are used: bypass grafting and percutaneous transarterial angioplasty. Acute myocardial attacks can be fatal. Ambulances equipped with defibrillators are needed in every community. Thombolytic therapy should be instituted immediately. The secondary prevention of stroke is early detection and effective treatment with warfarin and aspirin. The following groups of drugs are used in the treatment of hypertension: diuretics, beta blockers, ACE blockers, calcium channel blockers, alpha blockers, and vasodilators.
TERTIARY PREVENTION OF CARDIOVASCULAR DISEASE
Stroke victims require long periods of rehabilitation.
E. CHRONIC RESPIRATORY DISORDERS
OVERVIEW
Respiratory disease comes second to cardio vascular disease in importance as a cause of death in both developed and developing countries. Occupational respiratory diseases are declining because of better working conditions. The increased uptake of smoking in developing countries will translate into a higher incidence of respiratory disease in the future. The World Health Organization uses the term Chronic Non-specific Respiratory Disease (CNRD) to comprise chronic bronchitis, emphysema, and asthma. Emphysema/bronchitis demand a higher proportion of health resources. Methods of analysis of emphysema/bronchitis are questionnaire on symptoms, test of respiratory function, and sputum examination
INCIDENCE and MORTALITY
Mortality due to asthma is low. Asthma is a worldwide condition with rising incidence. In the UK UK UK
RISK FACTORS
Environmental tobacco smoke (ETS) causes lung cancer and childhood respiratory disease. ETS is a mixture of over 400 chemicals 85% of which are from cigarettes. ETS is a major source of indoor pollution. The more the number of smokers in the community the higher the exposure to ETS
PREVENTION
Primary prevention of chronic respiratory disease consists of identifying the harmful agents and removing them from the workplace. If removal is not feasible attempts must be made to minimize exposure. The concentration of the substances must be monitored continuously to make sure it does not rise above the threshold limit value (TLV). Workers should be informed about the harmful substances in the workplace so that they may take personal protective measures. A pre-employment screen can identify workers vulnerable to these diseases. A smoke free workplace enhances preventive efforts. Control of air pollution helps reduce COPD. Screening as a method of secondary prevention of COPD is not very effective.
10.4.2 PSYCHIATRIC AND NEUROLOGICAL DISORDERS
A. PSYCHIATRIC DISEASE
MENTAL HEALTH: Mental health is defined as the emotional and social wellbeing of an individual including competence in dealing with day to day problems of life. Good mental health includes spiritual calmness, a good self image, positive feelings about the self, other humans and tne environment, and being able to deal successfully with the demands of daily life. It includes emotional maturity with the ability to change and adapt to external forces, control of tension and anxiety, and other aspects of good character and correct human relations.
MENTAL DISORDER: A mental disorder is said to arise when there is a deficiency of psychological competence to deal with problems of daily life resulting into depression and psychological impairment. The following are the most important psychiatric disorders from the epidemiological perspective: drug dependency. Alcoholism, schizophrenia, anxiety, depression, suicide and parasuicide, eating disorders, and mental handicap.
HISTORICAL BACKGROUD: Mental health services were isolated from other public health disciplines because it was felt that they were a private problem with no clear outcome measures. This thinking has now been abandoned and mental health services have become fully integrated with other health services.
In pre-industrial society, it was believed that the mad were possessed by the devil and had to be exorcised. The insane were treated badly and cruelly being abandoned, beaten or chained. It was later realized that the mad were sick and needed treatment. They were housed in mental asylums and eventually were moved to the community.
US: In colonial America Pennsylvania Hospital became the first mental institution in the US
CLASSIFICATION OF MENTAL DISORDERS: Mental disorder diagnostic categories were traditionally classified as organic psychoses, functional psychoses, neuroses, personality disorders, substance abuse, mental retardation, disorders of psychological development, behavioral and emotional disorders of childhood and adolescence. Organic psychoses are due to genetic, biochemical, infective, and structural anomalies for example deliriums and dementias. Deliriums are acute syndromes and dementias are chronic syndromes. Functional psychoses are schizophrenia, manic depressive psychosis, and paranoid states. Neuroses are anxiety, phobia, depression, obsessive-compulsive disorders, and hysteria. Personality disorders are due to childhood influences and are paranoid, schizoid, and psychopathic disorders. Other disorders are addiction to alcohol and drugs, eating disorders, sexual dysfunction and sexual deviation. Organic states are due to metabolic disease.
The DSM classification of mental disorders has become more popular. DSM has the following categories: Disorders of infancy or childhood, organic mental disorders, Use of psychoactive substances, schizophremia, delusional (paranoid) disorder, mood disorders, anxiety disorders., somatoform disorders, dissociative disorders, sleep disorders, and personality disorders. Disorders of infancy or childhood eg retardation and attention deficit. Organic mental disorders such as Alzheimer’s disease and dementia. Use of psychoactive substances is characterized by intoxication, dependence, withdrawal, psychosis, the amnesia syndrome, and many physical complications. Dependence occurs when the drug-seeking behavior overrides all other aspects of life. The etiology of schizophrenia is not known. It is characterized by a split personality, delusions, and hallucinations. It is associated with impairment of affect, thinking, perception, and behavior. Delusional (paranoid) disorder. Mood disorders / affective disorders are classified as unipolar in depression only and bi-polar if depression alternates with mania. Depression leads to insomnia, diurnal mood variation being worse in the morning, loss of appetite, loss of libido, amenorrhea, anhedonia, and psychomotor retardation. Neurotic disorders are stress related somatoform disorders such as anxiety, phobia, panic, obsessive disorder, compulsive disorder, stress reaction, conversion (hysterical) disorders, hypochondria, and somatoform disorders. Dissociative disorders: multiple personality. Sleep disorders: insomnia, dream anxiety. Personality disorders are paranoid, schizoid, anti-social, borderline (emotionally unstable), histrionic, obsessive, compulsive, avoidant, dependent, and narcissistic personality disorders.
Stress is defined as psychological and physiological response to stressors. Stressors are stimuli in the physical and social environments that cause tension and strain. Stress leads to mental disorders. The stressors may be subtle such as waiting in a line or major life events like divorce. Stress affects health either directly or indirectly. Direct effects are physiological. Indirect effects are through behavior. The psycho-physiological disorders associated with stress are asthma, cancer, coronary heart disease, depression, dysmenorrhea, exhaustion, GIT problems (colitis, stomach pain, ulcers), headaches due to muscle contraction, hypertension, inflammatory bowel disease, and skin disorders (eczema, hives, psoriasis).
Homelessness and mental illness are related. De-institutionalization increased the proportion of the homeless. The homeless suffer from nutritional deficiencies, infections (TB, skin infections) and have a higher rate of traumatic injury, intentional and unintentional.
INCIDENCE and MORTALITY OF MENTAL DISORDERS: Determination of incidence rates is difficult because there is no agreement on diagnostic categories. Schizophrenia Prevalence is 1.1 - 5.1/1000 adults all over the world. Higher in DC. Peak age in mid-twenties. F>M. Anxiety: No complete data because most cases are unreported. F>M. Depression: No data; most cases unreported. IR is rising. Indigenous depression is worldwide. Suicide & parasuicide Parasuicide is now increasing. Eating disorders No data on anorexia nervosa and bulimia. Mental handicap No data
SOCIAL INDICATORS OF MENTAL ILLNESS: Suicide, homicide, divorce, alcohol and drug abuse, abuse and neglect are social indicators of mental illness. The suicide rate is the only clear outcome indicator of performances of mental health services.
RISK FACTORS OF MENTAL DISORDERS: Risk factors of mental disorders can be congenital, physical or psychological impairment, psychological causes, and idiopathic. Congenital risk factors may be genetic, idiopathic, or due to intra uterine exposure. Intra uterine exposure can be to physical agents, chemical agents, or may be biological (poor ANC and malnutrition).
TREATMENT OF MENTAL DISORDERS: Mental disorders are treated using biochemical therapy, psychotherapy, and behavioral therapy. Mental health care may be inpatient or outpatient. Community mental health services must be integrated in primary health care. Social services may have to intervene to provide transitional care facilities. The law provides for involuntary commitment and treatment based on a court order.
PREVENTION OF MENTAL DISORDERS: Primary prevention of mental disease involves decreasing/avoiding stressful events, treatment of physical disease, control drug addiction, identification of at risk groups. Secondary prevention is screening in primary health care settings, education, and follow-up of high-risk groups to prevent relapse. Prolonged maintenance neuroleptics treatment leads to a normal life for schizophrenics. Psychosocial treatment also helps. Tertiary prevention: long-term drug treatment leads to side effects that have to be dealt with. Social impairment must be dealt with. Institutional care may be necessary.
Primary prevention is by preventing infections, genetic counseling, better obstetric care, and control of drug and alcohol abuse. Secondary prevention is through health education. Tertiary prevention is drug maintenance, social support, and treatment of depression.
B. ABUSE OF ILLEGAL DRUGS
DEFINITIONS: A drug is a substance other than food that on entering the body in small amounts produces physical, emotional, and psychological change. Psychoactive drugs are drugs that act on the central nervous system. Drug use is a drug taking behavior whether appropriate or inappropriate. Drug misuse is inappropriate use of a legally purchased prescription or non prescription drug including both taking an overdose or an underdose. Drug abuse is use of a prescribed drug for a different purpose or excess alcohol and tobacco intake or use of illicit drugs in any amount. Drug dependence can be chemical, psychological or physical. Chemical dependence occurs when the victim feels that a drug is needed for normal functioning. Psychological dependence is emotional or psychological dependence. Physical dependence leads to clinical illness. Drug dependency manifests in several ways: more use of a drug than is intended, inability to reduce use, spending a big amount of time looking for the drug, physical effects of use, use of drugs replacing other activities, tolerance to the drug, and withdrawal symptoms. Poly drug dependence is dependence on more than one drug.
EFFECTS OF DRUG DEPENDENCE: Dependence on drugs has biomedical, pharmacological, psychological, and social effects. The effects may be acute or long-term. Some of the effects are indirect for example HIV infection and crime. Intravenous drug users share infected needles that leads to spread of HIV infection. Addicts are involved in crime to obtain money for drugs.
DRUGS COMMONLY ABUSED: The drugs commonly abused are marijuana, narcotics, and cocaine. Marijuana, cannabis sativa, is the commonest drug abused. It is smoked but can also be ingested. Its short term effects are lowered concentration, slower reaction time, impaired short term memory, and impaired judgment. Chronic use leads to the amotivation syndrome and chronic apathy. Marijuana synergizes with alcohol. Narcotics (opium, morphine, and heroin) numb the senses and reduce pain. They produce euphoria, analgesia, drowsiness, and anxiety. Tolerance leads to use of higher doses to achieve the same effects. Addiction is associated with crime. Cocaine is a stimulant and is very addictive. The introduction of crack cocaine was associated with increased violence in the US
INCIDENCE and PREVALENCE: Drug dependency Epidemic. IR is increasing. Alcoholism: Worldwide cause of mortality and mortality.
RISK FACTORS OF DRUG ABUSE: Risk factors may be genetic or environmental. Genetic factors operate in cases of alcoholic families and where genetic markers for alcohol addiction have been identified. Environmental factors may relate to personal, home or family, school or peers, and socio-cultural factors. Personal factors are impulsiveness, depressive moods, stress, and unstable personality. Events and phenomena in home and family life can cause drug abuse such as death, divorce, family turmoil, perenteral drug abuse, loss of self esteem leading to delinquency, noncomformity, sociopathy, and a positive family attitude to alcohol and drugs. Peer influence at school can be the start of a drug habit. The socio-cultural environment of the inner city with low SES and poor living conditions can encourage drug use. Strong law enforcement in the community prevents the start of the drug habit.
PREVENTION:
Primary prevention is preventing the initiation of drug use among those who have never used drugs. The main approach is drug education in the community and the schools. Education must start early before exposure to drugs. It can be carried out at home or in the community. Education should also include inculcating good values at home or at school. Other approaches are: parental supervision and involvement, interdiction of drug importation which raises the price and limits use but could increase crime, increased police activity to arrest drug pushers or prevent money laundering, and severe drug laws. Secondary prevention is aimed at those who already use alcohol and drugs but have not yet reached the stage of chronic use. They can be helped by drug education that reduces demand for drugs. Effective drug treatment and rehabilitation programs are also needed. Treatment starts with assessment of the condition. Abstinence initiation is followed by relapse prevention and follow up. Tertiary prevention provides treatment and after care.
NICOTINE ABUSE
Nicotine is a psychoactive and addictive substance. Cigarette smoking is the number 1 single modifiable cause of death. Environmental tobacco smoke increases cardiac and respiratory disease. It is associated with high economic costs.
ABUSE OF OVER THE COUNTER DRUGS
Over the counter drugs do not require a physician prescription. Examples of such drugs are cough and cold remedies, emetics, laxatives, mouth washes, and vitamins. OTCs can be misused. They have the potential to induce dependency as a prelude to illicit drug abuse.
ABUSE OF PRESCRIPTION DRUGS
Prescription drugs can be misused when patients give their drugs to other persons. Dependency can develop. Drug resistant strains of bacteria also develop.
C. ALCOHOL ABUSE
Alcohol has been used as a drug throughout human history for pleasure or in the wrong belief that it solves problems. Alcohol abuse is the number 1 drug problem as measured by the number of users, number of injuries, deaths, and economic loss. Alcohol abuse starts as social use which lowers anxiety producing a mild euphoria. Most users of alcohol are social drinkers. Problem drinkers are a minority who experience social, legal, and financial problems from their alcohol habit.
Alcoholism is physical dependence on alcohol and loss of control over drinking habits. Alcohol consumption becomes obsessive and withdrawal symptoms occur if consumption is stopped. Alcoholism is defined as a primary chronic disease with genetic, psychosocial and environmental factors influencing its development and manifestations. It is progressive and fatal. It is characterized by impaired control of alcohol consumption, preoccupation with alcohol, and distorted thinking involving denial.
Abuse of alcohol is a problem in youths and young adults. The problem is complicated by use of other drugs in addition to alcohol, poly drug dependency.
Alcohol abuse has health, psychological, social, and economic consequences for individuals and communities. The individual health consequences are fetal injuries, communicable and non communicable diseases, accidents, drug overdose, and death. The risk ratio among heavy drinkers of various conditions are as follows: liver cirrhosis RR=8.8, suicide RR=4.0, accidents RR=4.0, cancer of the upper esophagus RR=4.0, stroke RR=1.0, and overall mortality RR=2.0. The individual psychological consequences are drug psychosis, loss of self-esteem, and suicide. The individual social consequences are mental and family problems, financial problems, and criminal behavior. The individual economic consequences are absenteeism from work, under achievement at work and at school. The community consequences of alcohol are lower productivity, and higher public dependency, broken homes, sexually transmitted disease, crime, health care costs, police and prison costs. Alcohol is associated with violence manifesting as spousal abuse, traffic fatalities, murders, homicide, suicide, assault, rape, child abuse, and drowning.
RISK FACTORS OF ALCOHOL ABUSE: The causes of abuse are: genetic, family environment, low SES of parents, social isolation, poor living conditions, depression, low self-esteem, and psychological distress.
PREVENTION: Primary prevention of alcohol abuse is by programs for youths in schools, families and communities: inculcating values, information about alcohol, health education, and providing alternative activities. Other primary prevention measures are restricting the age of drinking, restricting hours of drinking, times and places of sale, control of alcohol advertisement in the media, and increasing taxes on alcohol. Secondary prevention of alcohol abuse consists of early detection and early treatment. Treatment of alcoholism could take any of 3 alternatives: (a) outpatient methadone treatment (b) therapeutic communities (c) outpatient drug-free treatment.
D. MENTAL RETARDATION
DEFINITION: There is no agreement on the definition of mental retardation. Clinical assessment is not enough. Different examiners use different scales. Concepts are also not standardized. This results in terminology being confused. Four categories of mental retardation can be defined: intellectual impairment, generalized learning disability, and specific disabilities or handicaps. Intellectual impairment is measured using the intelligence quotient, IQ. IQ below 50 is considered severe intellectual impairment. IQ of 50-69 is considered mild intellectual impairment. The use of IQ is not valid for all situations and should be interpreted with care. A child with a learning disability needs special or remedial education. The causes of learning disability are: intellectual impairment, motor impairment, sensory impairment, social deprivation, educational deprivation, childhood psychosis, poor schools, and poor teachers. A low IQ is an important criterion in defining mental handicap. Mistakes in categorizing persons as mentally handicapped occur and are due to sex, social class, and racial biases. Some forms of mental retardation are a result of physical impairments like the feto-alcohol syndrome, Alzheimer's disease, Down's syndrome, and cerebral palsy. Specific disabilities eg autism.
INCIDENCE AND PREVALENCE: Epidemiological data of good quality is limited. Incidence of mental retardation is difficult to measure. Data on prevalence is available and shows wide variations. Mental retardation is increasing in adults because of increased survival.
RISK FACTORS: Intellectual impairment may be due to organic syndromes: chromosomal and neurological. The primary chromosomal factors are Down’s syndrome, sex chromosome disorders, and other autosomal anomalies. The primary neurological disorders are are defects of protein metabolism such as PKU, defects of carbohydrate metabolism such as gatactosemia, defects of lipid metabolism such as Tay-Sachs disease, and defects of mucopolysaccharide metabolism such as Hurler’s syndrome. Secondary organic syndromes are antenatal, perinatal, and postnatal. The antenatal factors are iodine deficiency, Rh incompatibility, alcohol, and drugs. The perinatal factors are trauma, hypoxia, hypoglycemia, and cerebral thrombosis. The post natal factors are trauma, infection, chemical agents, and nutritional or metabolic disorders.
SERVICES FOR THE MENTALLY RETARDED: Philosophy of caring for the mentally retarded: care in the community vs institutions. The concept of normalization.
PREVENTION: Primary prevention: health promotion & specific protection. Pre-marital screening and genetic counselling can prevent some inheritable causes. Immunization against common childhood infections. Immunization of the mother against rubella prevents the rubella syndrome. Lead control programs prevent mental retardation in children due to lead exposure. Overall socio-economic development removes many of the causes of mental retardation. Secondary prevention: This involves early treatment to limit disability and start rehabilitation. Pre-natal screening can help detect some conditions so that treatment can be instituted in utero or soon after birth. Neonatal screening is now available for many metabolic disorders that may cause mental retardation
Tertiary prevention limits severity and complications.
E. NEUROLOGICAL DISORDERS
NEUROEPIDEMIOLOGY
The diagnosis of neurological disease is difficult primarily because case definition is noit easy. Prevention of neurological disease takes on added importance because regeneration of damaged nervous tissue is limited. The following are the neurological disorders of epidemiological importance: migraine headache, stroke, back pain, epilepsy, Parkinson’s disease, peripheral nerve disorders, dementia, Alzheimer’s disease, multiple sclerosis, and cerebral palsy. Headaches can be vascular such as migraine, due to muscular tension, or symptomatic due to infection, trauma. Or hemorrhage. Migraine is unilateral and is preceded by premonitory signs of visual disturbance, nausea, and vomiting. Back pain is a universal complaint whose definition is not unanimous. Epilepsy is defines as 2 or more seizures unprovoked by any immediate identifiable cause. An epileptic fit includes altered consciousness, motor events, sensory events, and psychic events. EEG may be normal in an epileptic. Parkinson’s disease is difficult to define. Mononeuropathies include the carpal tunnel syndrome due to repetitive trauma, Bell’s palsy, diabetic peripheral neuropathy, lepromatous neuropathies, and nutritional neuropathies (deficiency of vitamins B and E), and toxic neuropathies. Senile dementia is progressive loss of cognitive ability in the elderly. It manifests in two main forms: as vascular dementia and as Alzheimer’s disease. Vascular dementia follows stroke and diagnosis is based on evidence of cerebrovascular disease and brain imaging. Epidemiological characterization is not easy because there is no clear case definition. The diagnosis of multiple sclerosis is based on clinical presentation and MRI. Case finding is not easy. Lesions are often clinically silent. Cerebral palsy is a non progressive motor handicap in children.
INCIDENCE and MORTALITY
Migraine headache is the most prevalent neurological disorder. It is a familial condition that occurs early in life. The peak age at incidence is 40. Incidence is higher in females than in males. The higher female incidence may be related to sex hormones since it has been observed that oral contraceptives and pregnancy increase the severity of the disease. It has no SES association but those in high SES seek diagnosis more often than those in lower SES.
Backache incidence increases with increase of age to peak at 55-64 years. The following professions are at a higher risk: nurses, drivers, manual workers, miners, and lumber workers.
Epilepsy is worldwide but incidence is higher in tropical regions. The UK
Parkinson’s disease occurs all over the world. Its incidence of Parkinson’s disease increases with age. The prevalence of Parkinson's disease in UK is 1/1000 of population and rises to 1/200 in those aged above 65 yr. Incidence is highest in Caucasians, intermediate in Africans, and lowest in Asians. Males are affected more than females. No changing trends have been observed over the past 50 years indicating that incidence is not affected by environmental changes.
Senile dementia is manifesting increasing incidence in the elderly. Alzheimer's disease incidence rises with age and is associated with increased mortality. The UK
The prevalence of cerebral palsy in UK
Multiple sclerosis occurs world-wide with higher incidence in cold climate. The incidence rate in England
Data on anencephaly and hydrocephaly is not available. Spina bifida affects males more than females. Headache is a common cause of morbidity worldwide and has several causes. It is surprising that such a common condition does not have the attention it deserves from epidemiological researchers. There are several types of neuropathies with a wide range of causes. Paraplegia is increasing due to road traffic accidents.
RISK FACTORS
Migraine is familial but the genetic predisposition is not fully understood. Stroke is associated with migraine. The risk factors of backache include age, occupation, psychosis and stress. The causes of epilepsy may be perinatal (infections, low birth weight, maternal malnutrition, maternal anemia, preterm delivery, aged motherhood, and cerebral palsy), febrils seizures, head injuries, parasitic infections (such as trypanosomiasis), toxic agents (lead, alcohol) or heredity. No definitive risk factors of Parkinson’s disease are known but the following are suspected: neurotoxins, head trauma, smoking, infections and a possible sequela of other diseases. The risk factors of vascular dementia are hypertension, hyperlipidemia, ischemic heart disease, family history, age and the male gender. The risk factors of Alzheimer’s disease are age and female gender. There is no conclusive evidence for any other risk factors. Multiple sclerosis may have an infective cause operating in early childhood because migrants keep the risk profile of their childhood residence. Low birth weight is a predictor of cerebral palsy. Parental education and low SES are not predictors.
PREVENTION and CONTROL
Migraine: Prevention of migraine is based on teaching the individuals to recognize the triggers. Analgesics are then used to abort attacks. Prevention of back ache is by education on proper spine positions during lifting heavy loads, use of lumbar supports, and better ergonomoic design. Prevention of epilepsy is based on treatment of infections, good antenatal and perinatal care, and prevention of head injuries. Prevention of Parkinson’s disease can not be defined exactly. It may lie in dietary improvement, use of antioxidants and supplementary vitamins. There is no known preventive measure for multiple sclerosis. Prevention of cerebral palsy is based on prevention of low birth weight. Magnesium administered to mothers of potential very low birth weight babies is a preventive measure.
10.3.3 GASTRO-INTESTINAL, GENITO-URINAL, METABOLIC DISORDERS, and ENDOCRINE DISORDERS
A. ORAL DISORDERS
OVERVIEW
Untreated dental disease is associated with seceral complications including masticatory difficulties leading to malnutrition, impairment of speech, and disfigurement that leads to social stress. The main oral disorders are: dental caries, periodontal disease, malocclusion and dento-facial abnormalities, oral musocal disease, and oral malignancies. Dental caries are due to decalcification of the enamel by action of organic acids produced when oral bacteria act on sucrose. Only a few of the oral normal flora are carcinogenic the most important being strep mutans, actinomyeses spp, and lactobacillus spp. Saliva helps buffer the acids and has minerals (calcium, phosphorus, and fluorine) that help in remineralization. Periodontal disease starts as gingivitis which progresses to periodontitis. The infection is due to microorganisms in the plaque that colonize the gingival crevice. The primary pathogens are actinobacillus, actinomycetes spp, porphyromonas gingivalis, provotella intermedia, eikelnella corrodens, and fusobactarium nucleotum.
EPIDEMIOLOGICAL MEASURES OF ORAL DISEASE
The DMF index is used to indicate D = number of decayed teeth, M= number of missing teeth, F= number of filled teeth. The Oral Hygiene Index (OHI) and the Plaque Index (PI) are used to assess periodontal health. Gingivitis is assessed using the gingival index, the periodontal disease index, and the community periodontal Index of Treatment Need (CPITN).
INCIDENCE AND MORTALITY
Diseases of the teeth and surrounding structures have a high prevalence. Dental caries became prevalent in the 19th and 20th centuries due to increasing consumption of refined foods and sugar. Dental caries' incidence is increasing worldwide. The incidence of caries is higher in developed countries with peaks in childhood and adolescence but is falling due to awareness. It is rising in developing countries as dietary practice changes with material development. Caries are found more in the low SES due to delay is seeking treatment. Periodontal disease occurs more in rural than urban areas. Males are affected more than females.
Periodontal disease is prevalent in developing countries. Its severity increases with age. It is associated with poor oral hygiene. It is more common in rural areas. Males are affected more than females. The uneducated and users of tobacco have higher prevalence.
The following are encountered as craniofacial malformations: cleft lip, cleft palate, jaw deformities, dental anomalies, too wide spacing of teeth, too narrow spacing of teeth, facial asymmetry, and the fetal alcohol syndrome.
RISK FACTORS
Low salivary flow is a risk factor for dental caries. The main risk factors of dental are dietary; taking refined food with high sugar content. Poor oral hygiene is the main risk factor for periodontal disease. The risk factors for cleft lip are thought to be environmental insults in pregnancy (maternal disease, chemotherapy, radiation, alcohol, excess retinoic acid, and anti-convulsant therapy) or genetic factors. About 90% of oral malignancies are squamous cell carcinoma whose risk factors are tobacco and alcohol. It is suspected that viruses such as EBV, CMV, and HPV are involved.
PREVENTION
Dental caries are prevented by use of fluoride. It can be added to community water supplies, milk, salt can be given as topical fluoride or as fluoride supplements. Fluoride makes the enamel more resistant to caries. Occlusal sealants help prevent contact of the tooth enamel with the careous acids. Good oral hygiene involves plaque removal, regular brushing, and flossing. Dietary modifications involve decreasing fermentable carbohydrates, increasing the amount of fiber in the diet, and taking adequate phosphorus and calcium. Care must be taken to avoid damaging salivary glands during operations on the mouth. Where salivary flow is inadequate, artificial saliva can be used.
Periodontal disease is prevented by oral hygiene, professional tooth cleaning every 6 months, and mechanical plaque removal done by the patient or a dental hygienist.
B. GASTRO-INTESTINAL DISORDERS
OVER-VIEW
These diseases are due to exposure to the environment. Food and other ingested materials that travels through the alimentary canal is part of the external environment. The canal is an interface between the internal and external environments.
INCIDENCE and MORTALITY
There are several liver diseases of epidemiological importance: acute hepatitis, cirrhosis, hepatocellular carcinoma, and Raye’s syndrome. Liver cirrhosis is an end-stage condition that leads to liver failure and death. Alcoholic cirrhosis occurs in Europe and America Africa . Pancreatitis is difficult to diagnose. The incidence of acute pancreatitis in UK Sweden is 27.5/100,000, in Minnesota UK UK Africa . Appendicitis has an increasing incidence but falling mortality. Incidence is higher in developed countries. Peak incidence is at 5-44 years. Male incidence is higher than female incidence. Diverticular disease of the colon has low mortality. It has higher incidence in the developed countries and is associated with higher SES. Females are affected more than males.
RISK FACTORS
Alcohol is the main risk factor of cirrhosis in Europe and America
PREVENTION
Liver cirrhosis is prevented by avoiding alcohol and HBV vaccination. Prevention of cholelithiasis is mostly dietary. Prevention of celiac disease is by decreasing dietary gluten intake. Infant feeding can rely on breast feeding with delayed introduction of gluten containing foods. Prevention of appendicitis is undefined since its determinants are not yet established. Prevention of diverticula disease is probably by increasing dietary fiber.
C. GENITO-URINARY DISORDERS
D. METABOLIC DISORDERS
E. ENDOCRINE DISORDERS
OVER-VIEW
The major metabolic diseases are diabetes mellitus, iodine deficiency disorders, and osteoporosis.
Diabetes mellitus is defined with hyperglycemia as a central feature. Two main forms of diabetes may be defined. Insulin dependent diabetes (IDDM) is the most serious form. Non-insulin dependent diabetes (NIDDM) is found in both the obese and non-obese. Diabetic conditions may also be found associated with some forms of malnutrition, pancreatic disease, ingestion of some drugs and chemicals, and pregnancy (gestational diabetes mellitus). Impaired glucose tolerance (IGT) may be found in both the obese and non obese. IDDM is due to loss of islet cells of the pancreas. The complications of diabetes are microvascular (retinopathy, nephropathy, and neuropathy) or macrovascular (atherosclerosis).
Hypothyroidism is an iodine deficiency disorder. Iodine is a component of the important thyroid hormones T4 and T3. Mountainous areas are usually iodine deficient. The ocean is a major reservoir of iodine. Sunlight oxidizes iodine to a volatile form that escapes into the air and is returned to the soil with rain. Iodine deficiency is the main cause of goiter. The fetal effects of iodine deficiency are stillbirth, abortion, congenital anomalies, and brain damage. Neonatal iodine deficiency leads to neonatal goiter and brain damage. Iodine deficiency in children leads to goiter, loss of energy, impaired school performance, retarded physical growth. Iodine deficiency in adults causes goiter and its complications, loss of energy, and impaired mental functioning. Goiter is classified as grade 0 when it is not pulpable or visible. Grade 1 goiter in palpable but not visible. Grade 2 goiter is visible with the neck in its normal position. Iodine status is assessed using thyroid size, urine iodine excretion, and T4 or TSH serum levels. Neonatal iodine screening is carried out where needed. Iodine deficiency is corrected by using iodized salt, iodized milk, or injection of iodized oil.
Osteoporosis is a disease of low bone mineral deposit (BMD). It is a condition of public health importance because of the associated fractures of the hip, spine, and forearm. The basic pathology is bone loss as a result of imbalance between bone formation and bone resorption. Primary osteoporosis is due either post menopausal or senile. Secondary osteoporosis is due associated with acromegaly, hypothyroidism, and the Cushing syndrome.
INCIDENCE and MORTALITY
The incidence of diabetes in increasing and it is feared that it may become an epidemic in some places. The incidence of IDDM is lower than that of NIDDM. IDDM has a prevalence of 2% in the UK UK
Hypothyroidism, associated with goiter and cretinism, occurs in China , SE Asia, Latin America, and Central Africa . No data is available on hyperthyroidism, adrenocortical insufficiency, and adrenocortical excess (Cushing') syndromes.
RISK FACTORS
The risk factors of IDDM are both genetic and environmental. Variation of incidence over time, by ethnicity, and among migrants suggest environmental factors. NIDDM has both genetic and environmental factors. It is associated with lifestyle, physical inactivity, obesity, fat distribution, and poor nutrition.
PREVENTION
Preventive possibilities for endocrine and metabolic disorders are limited. Screening for diabetes was touted as a preventive approach however interest in screening for diabetes has waned because many causes of minor glucose intolerance are not significant on follow-up. Prevention of NIDDM depends on lifestyle changes in diet, exercise, smoking, and alcohol intake. Control of blood sugar levels reduces both microvascular and macrovascular complications. The microvascular complications are retinopathy, nephropathy, and neuropathy. The macrovascular complications are atherosclerosis, myocardial infarction, angina pectoris, stroke, and aneurysms.
10.4.4 TRAUMATIC, MUSCULOSKELETAL, and CONNECTIVE TISSUE DISORDERS
A. TRAUMATIC INJURY
DEFINITION: Traumatic injury is physical harm or injury to the body resulting from an exchange usually acute of mechanical, chemical, thermal, and other environmental energy that exceeds the body’s tolerance. Injuries may be intentional or unintentional. The term unintentional injury is preferred to the term accident because injury is never accidental. There are always preceding or pre-disposing unsafe acts or conditions that could have been altered to prevent the injury. Injuries occur at home, at work or on the road.
The general public is not aware that injuries are preventable. The word accident is a misonomer. Nothing is accidental. There are always antecedents of an accident that can be modified.
CLASSIFICATION: Injury can be classified as unintentional and intentional. Unintentional injury is motor vehicle crashes, falls, fires, drowning, injury at the workplace, and natural hazards such as floods, tornadoes, earthquakes, and hurricanes. Intentional injury may be self directed or interpersonal. Self directed intentional injuries are suicide and suicide attempts. Interpersonal intentional injuries are assaults, homicide, elder abuse, child abuse, sexual assault, spousal violence, and child sexual abuse. School violence. Most instances of domestic violence are not reported to the police. Domestic violence between intimates may be physical, sexual, or verbal and women are usually the victims.
INCIDENCE: Incidence: Data on injuries is mortality, morbidity, impairment, and disability rates. The incidence rate of injuries is increasing. Victims of injuries include children, youths, and the elderly. About 50% of fatal accidents occur in the home. Children <4 years and the elderly are at higher risk. Males are more prone to accidents than females. The lower socio-economic classes have more injuries due to lifestyle and risky physical environment. There are seasonal variations in incidence depending on the type of activity involved in causing the injury. Economic loss: Economic loss results as a result of injury or death. The loss is measured as years of potential life lost, YPPL. YPLL for injury is higher than cardiovascular or cancer deaths.
RISK FACTORS: Males of all races are at a higher risk for injury. Children and the elderly are victims of unintentional injury. The behavioral risk factors for physical injuries are either environmental or psychological. The environmental risk factors are alcohol and drug abuse, and being a victim of violence early in life, media violence, peer/community violence, poverty, hopelessness, unemployment, low self esteem, and availability of firearms. Psychological factors are stress and a violence-prone personality. Alcohol and drug abuses increase suicide and homicide. Road Traffic accidents are increasing due to more use of motorized transport.
INJURY PREVENTION: Epidemiological model for prevention: A traumatic injury can be visualized as a 3-way interaction among energy, the host and the environment. The preventive steps that can be taken are therefore: reducing the energy, preventing or reducing energy release, putting a barrier between the host and the energy source, and separating the host from the source of energy. Primary prevention of unintentional injury prevention: (a) injury prevention education, (b) regulation (c) automatic protection (d) litigation. Primary prevention of intentional injury prevention: education: reduction of media violence, education on anger control and conflict resolution, gun control, socio-economic improvement, enforcement of regulations, counseling and treatment. Secondary prevention is by early identification and screening, behavior modification, early intervention in the school, counseling, family support, and risk factor identification. Tertiary prevention in jail/prison for criminalsm rehabilitation and hospital services for victims. Prevention of motor vehicle injury. Primary prevention of motor vehicle injuries includes: driver education, laws against drunk driving, speed limits, use of tachometers to control speed, improved road definition using striping and reflectors, improved visibility of vehicles by lighting and reflectors, use of vehicle headlamps even in the day, high mounted brake lights, reduced glare in the driver’s eyes, improved brakes, increasing vehicle stability, separation of heavy and light vehicles on the road. Secondary prevention of motor vehicle injury: restraint laws, use of automatic seat belts, use of energy absorbing materials like air bags, removal of rigid structures within the vehicle, removal of flammable materials in the interior of the vehicle and the tires, improved skid resistance roads, improved door latching systems to prevent ejection from the vehicle, side door and roof crush resistance, and seat integrity. Secondary prevention also involves CPR training, acute medical care. Tertiary prevention is physical therapy, occupational therapy, and speech therapy. Passive interventions like air bags are more effective than active intervention measures like seat belts. Prevention of pedestrian injury: Primary prevention of pedestrian injuries involves education of the drivers and pedestrians and identifying high-risk areas for pedestrians. Injury to bicycle riders is due collision with motor vehicles. Primary prevention involves wearing helmets and providing separate lanes for bicycles. Prevention of fire injuries: Cigarette smoking is the commonest cause of house fires. Primary prevention of injury due to fire and smoke involves using smoke detectors, sprinkler systems, and education about causes of fires and how to avoid them. Prevention of drowning: Drowning occurs in bath tabs, buckets, swimming pools, rivers, floodwaters, and oceans. Primary prevention involves teaching children to swim and fencing swimming pools.
B. INTER PERSONAL VIOLENCE
The rate of homicide is increasing among the youth to almost epidemic levels. In most cases the victim knew the assailant. Homicide may be committed alongside another felony. The media might have played a role in the genesis of the violence epidemic by showing violent movies.
C. PHYSICAL DISABILITY and HANDICAPS
DEFINITION and CLASSIFICATION: Three terms need clarification: impairment, disability, and handicap. The World Health Organization defines impairment as any loss or abnormality of psychological, physiological, or anatomical structure or function. Impairment turns into a disability when there is reduction of normal activity. Disability is used with reference to the person whereas impairment is organ or tissue specific. A handicap is a disadvantage for a given individual resulting from an impairment or a disability that limits or prevents the fulfillment of normal roles. Types of physical disabilities. In disability rehabilitation is accepted instead of cure
INCIDENCE and PREVALENCE: The following can be used to assess the size of the disability problem in the community. (a) routine statistics (b) special surveys (c) data from hospital-based services (d) data from community-based services. Epidemiological studies. The number of babies with congenital anomalies surviving is increasing
ASSESSMENT: Needs assessment is necessary for planning service delivery. Medical records can provide limited data because some persons with disabilities do not go to hospitals. Demand for services is an indicator of the needs. This however may be skewed if persons with some disabilities are more vocal than others. For the individual an independent clinical assessment may be carried out to determine the level of disability and thus determine the type of service needed. Some aspects of disability are social and psychological and require specialist assessment. Social functioning can be assessed as activities of daily living, ADL. Vulnerable groups: The following are more vulnerable than others to disabilities: pre-school children, school children, workers, and the elderly
SERVICES FOR THE PHYSICALLY DISABLED: Services for the handicapped may be hospital-based or community-based.
PREVENTION
D. MUSCULOSKELETAL DISORDERS
OVER-VIEW
Musculo-skeletal disorders are classified as joint diseases (rheumatoid arthritis, osteoarthritis, gout, degenerative joint disease, spondyloarthropathies such as ankylosing spondylitis), non articular conditions (intervertebral disks disorders, neck disorders, and back disorders, upper limb pain, fibromyalgia), and generalized systemic conditions (systemic lupus erythromatosus, Reiters’s syndrome, scleroderma, vasculitis, Sjogren’s syndrome. The criteria of diagnosis and classification of these diseases are vague. Rheumatoid arthritis is an inflammatory condition of unknown cause. Ankylosing spondylitis is an inflammatory disease that results in the fusion of the spine and is diagnosed radiologically. Osteoporosis is a common cause of fractures of vertebrae, the hip, and the distal radius following a fall. It does not cause spontaneous fractures. Its diagnosis is based on measuring bone density using dual x-ray absorptiometry. The definition of bone density is vague. Osteoarthrosis is stiffening of bones and joints due to loss of cartilage from the joint space accompanied by osteocyte formation and pain. It is diagnosed radiologically. Lesions diagnosed radiologically may not be accompanied by pain.
INCIDENCE and MORTALITY
The measures of disease occurrence used for musculo-skeletal and connective tissue disorders are the incidence rate of new cases, episode incidence, cumulative incidence, point prevalence, and period prevalence. The commonest disorders are rheumatoid arthritis, osteoarthritis, intervertebral disk disorders, neck and back disorders.
Rheumatoid arthritis affects 2-3% of the UK America Asia . The prevalence in males in of 0.5% in UK
Osteoarthritis has a UK prevalence of 35% in those aged below 30 yr and 85% in those aged 85 yr. OA is rare below the age of 50 years. Incidence rises with age. Hip OA is less common in Asia and Africa but knee OA demonstates less geographical variation.
Gout, uncommon before puberty, has a UK UK
Osteoporosis is rare below the age of 50. It affects females more than males with incidence rising with age. Incidence is higher and is rising in Europe and America
Rickets is common in developing countries and poor areas of developed countries. Paget's disease affects 4% of the UK
RISK FACTORS
Rheumatoid arthritis may have an autoimmune cause. Ankylosing spondylitis has a genetic basis. The risk factors for osteoarthritis are knee injury and stress injury due to obesity. The risk factors of non-articular musculoskeletal pain are increasing age, gender with males being at higher risk, low SES, psychosocial stress, and physical stress.
PREVENTION
Prevention of oseoarthritis is based in weight reduction and arthroplasty. Low back pain is prevented by education and exercises. Surgery is of limited and uncertain value.
E. HEMATOLOGICAL DISORDERS
E. HEMATOLOGICAL DISORDERS
INCIDENCE and MORTALITY
Hematological disorders: Anemia is more in pregnant & lactating women and children of poor communities. Sickle cell disease is found in equatorial Africa, India , the Middle East, and the Mediterranean . Alpa thalassemia is found in the Far East, the Middle East, and Africa . Beta thalassemia is largely a Mediterranean disease of infancy and childhood. No information is available on the hemolytic disease of the newborn and chronic myeloid leukemia. Acute myeloid leukemia (AML) has a UK UK UK UK UK UK UK
RISK FACTORS
PREVENTION
E. SKIN DISORDERS
INCIDENCE AND MORTALITY
Skin disease: Psoriasis has an UK Japan and West Africa . Its incidence peaks at puberty and menopause. Ichthyosis (scaly skin) has a UK UK UK UK
RISK FACTORS
PREVENTION
UNIT 10.5
AGE-RELATED CONDITIONS
UNIT OUTLINE
10.5.1 MATERNAL DISORDERS
A. The Family
B. Maternal Morbidity and Mortality:
C. Reproductive Epidemiology
10.5.2 CHILD DISORDERS
A. Normal Growth and Development
B. Child Morbidity and Mortality
C. Preventive Interventions
D. School Health Programs
E. Epidemiology in Child Health
10.5.3 ADOLESENT HEALTH CARE
A. Definition and Characteristics of Adolescence
B. Psycho-Social Problems of Adolescents
A. THE FAMILY
FAMILY AS A BASIC SOCIAL AND HEALTH UNIT
The family is the basic unit of social organization that mirrors all else going on in the society. Good healthy family leads to a good community and good nation. Traditionally all health care was provided in the family. The family still has a role in preventive and curative medicine being the first point of contact.
TRADITIONAL FAMILIES
Extended family: The extended family included relatives and in-laws who provided mutual material and psychological support for one another. It was however stressful to live in such a family with the crowding that happens
The nuclear family: Husband, wife and children. Husband worked and the wife looked after children
NON-TRADITIONAL FAMILY
Families with both parents working and families headed by a single parent are non-traditional families with new stresses that impact on life and health.
CHANGING FAMILY DYNAMICS
Family composition: Industrialization and urbanization have caused many changes in the family structure and function. Urbanization had increased the importance of the nuclear family at the expense of the extended family. The size of the household is decreasing. The proportion of elderly people in the population is increasing without the resources of the extended family to support them. The traditional family is also being threatened by the increasing rate of family break-up as a response to stresses of industrial society
Fertility: Changing ideas about the role of women, new lifestyles, and female involvement in the work-force have reduced fertility levels. The natural rate of fecundity is estimated 45-50 per 1000 women. The birth rate in Europe in the 19th century was already below this indicating that contraceptive practice has been around since the last century. Birth rates are falling world-wide in both developed and developing countries.
Demographic changes: The age at first marriage is rising and teenage marriages are rare. More mothers are employed outside the home in the work-force. Many families have both parents working and they return home too exhausted to take care of their parental duties. The number of are witnessing increasing teenage births and births to unmarried women. The adverse effects of single teenage births are not due to biological factors but are due to lack of financial and social support. The rate of divorce is rising. Divore has both immediate and long-term effects on the children. An increasing number of children are living in poor one-parent families. Poverty is a factor of stunted growth, poor academic performance, low rates of immunization, and a higher risk of child abuse. Later sequalae of divorce on children are depression, fear, anger, behavioral problems, school drop-out, and poor health. The divorced parents are also not spared the physical, financial, and psychological consequences of divorce. Family disruption is the cause of runaway children, suicide or homicide, delinquency, crime, and drug abuse.
Consequences of changes in family demographics: The major consequence of the demographic changes in the family is the increase of poverty in female-headed households. Children growing up in poverty suffer from the following: stunted growth, high blood lead levels, lower hemoglobin levels, low immunization rates, higher hospital admissions, more severe episodes of illness, psychological stress, homicide, runaway children, and abuse (physical and sexual). Lack of a psychological support network leads to stresses.
Family social and financial welfare: Over the past half century, legislation has been passed in UK
B. MATERNAL MORBIDITY AND MORTALITY:
DEFINITION
Maternal mortality is defined as number of deaths per 100,000 live births in a given year. This includes only deaths due to complications of pregnancy, child birth, and the puerperium. The immediate antecedents of maternal mortality are ectopic pregnancy, spontaneous abortion, hemorrhage (intra-partum and post-partum), toxemia, and puerperal complications such as infections. Maternal mortality and IMR are good indicators of a community’s health status. Maternal mortality rates have been falling due to fall in the incidence of pregnancy complications such as hemorrhage, toxemia, and infections. Maternal and infant mortality have been falling in almost all countries. This is due to improved socio-economic conditions and better medical services.
RISK FACTORS
Poor prenatal care and teenage pregnancy remain the main causes of maternal morbidity and mortality. Poverty, lack of education, and lack of access are barriers to getting pre-natal care. Teenage mothers are often unmarried, poorly educated, and poorly nourished. Babies of teenage mothers are at a higher risk of low birth weight, prematurity, IMR, and lower IQ scores. Strenuous work in pregnancy causes low birth weight. Occupational exposures have reproductive effects. Investigations of the reproductive effects of the following exposures are being undertaken: chemical and pharmaclogical agents, physical agents, job stress, biological agents, and metals. Chemical and pharmacological agents include: anti-neoplastic drugs,hormones, anesthetic gases, vinly chloride, organic solvents, methyl mercury, ethylene oxide, pesticides, herbicides, polycyclic aromatic hydrocarbons, styrene, trichloroethylene, benzene, and formaldehyde. Physical agents are radiation, x-rays, and heat. Biological agents are infections by cytomegalovirus, rubella virus, toxoplasmosis, Lyme disease, Hepatitis B virus, and the human immunodeficiency virus.
HEALTH SERVICES FOR MOTHERS
The following are services for mothers: birth control, ante-natal care, delivery, and post-natal care. Training in parenting, breast-feeding, and cooking are essential mothercraft skills. Good child health care is indirectly a service for mothers. A mother who had good care as a child will grow up more healthy physically and psychologically and able to shoulder the stresses of child bearing and child rearing. Studies have shown the inter-generational transfer of physical and psychological scars. Malnourished girls grow up to be mothers with a bad obstetric career. Abused children grow up to be abusive parents. Preventive services for mothers are primary, secondary, and tertiary. Primary preventive services are counseling about nutrition and behavior. Secondary preventive services are screening for syphilis, HIV, and Rh. Tertiary preventive services are controlling existing conditions such as HT, DM, and toxemia of pregnancy.
SOCIAL WELFARE OF MOTHERS
Laws prevent discrimination against pregnant mothers. Maternity leave (paid and unpaid). Day care facilities. Special protection for mothers in the workplace not to be exposed to teratogenic substances.
FAMILY PLANNING SERVICES
Family planning is a type of health promotion by ensuring adequate spacing., OC is contra indicated during breast feeding because it decreases milk output and shortens the duration of breast feeding.
C. REPRODUCTIVE EPIDEMIOLOGY
OVER VIEW
The reproductive life events fall between menarche and menopause. The menstrual cycle characteristics are described in the form of ovulation, length, and duration. Time to pregnancy studies. Timing and spacing of pregnancy. Prenatal care and work outside the home have an effect on reproductive life.
The end points in reproductive epidemiology are infertility, abortion, pregnancy, birth, birth defects, still births, maternal and infant mortality. Infertility is inability to become pregnant after 12 months of regular sexual intercourse. Case control studies can be used to study causes of infertility. Pregnancy loss may be recognized or may be sub-clinical. Pregnancy complications include pre-term/LBW deliveries and pre-ecclampsia. Low birth weight may be due to intra-uterine growth retardation (IUGR). Birth weight has an inverse relationship to mortality and weight-specific mortality rates can be computed. Relative birth weight is computed as the deviation of birth weight in standard deviation units from the mean. Birth defects may be genetic or environmental (rubella, thalidomide, and DES). Case control studies can be used to identify causes of birth defects. Gene typing helps identify genetic causes.
INCIDENCE and MORTALITY
Obstetric and gynecological disorders. Teenage pregnancy is increasing worldwide. There is also an increase in births to elderly primigravida (age >35 yr at 1st delivery). Multiple pregnancy is more common in Asians and Africans than Caucasians. Complete data is not available on abortion, ectopic pregnancy, ecclampsia, and maternal mortality
RISK FACTORS
Risk factors of poor pregnancy and infant outcomes can be divided into the socio-demographic, medical, pregnancy-related, lifestyle, and environmental factors. The socio-demographic risk factors are age (below 17 and above 34), poor socio-economic status, single motherhood, and low levels of education. Medical problems may include heart disease, diabetes, sickle cell anemia, thyroid disease, hepatitis, asthma, tuberculosis, hypertension, and malignancy. The pregnancy-related risk factors are either in the current pregnancy or the obstetric and gynecological history. Risk factors in current pregnancy include: anomalies of the uterus (irritable uterus), anomalies of the cervix (incompetent cervix), anemia, bleeding, Rh isoimmunization, multiple gestation, pre-mature rupture of membranes, pre-ecclampsia and ecclampsia, placenta previa, deep venous thrombosis, and infections. Risk factors in the obstetric and gynecological history include history of pre-term or low birth weight delivery, high parity, short interval since last pregnancy, and history of ecclampsia. Life style risk factors are smoking, alcohol, drug abuse, poor nutrition, stress and lack of social support. Environmental risk factors are toxic exposures, occupational exposures, and strenuous work in pregnancy.
10.5.2 CHILD DISORDERS
A. NORMAL GROWTH AND DEVELOPMENT
Growth refers to physical growth of the body. Development refers to increasing functional maturity and specialization. Pre-natal growth is affected by maternal illness, maternal smoking, maternal hypertension (causes low birth weight), and maternal diabetes mellitus (causes high birth weight). Birth weight is a good indicator of pre-natal growth. Post-natal growth is best measured by weight and height that are generally used as surveillance for child growth and wellbeing. They are affected by: calorie intake, genetic inheritance, physical health, psychological well-being, weight at birth, and maternal age. Height is a reliable indicator because it measures growth in only one tissue, the bone. Height velocity curves are sensitive to changes in health and nutrition. The age at puberty is affected by genetic inheritance, ethnicity, seasonal variation, SES, secular trends, and nutrition. It has been progressively decreasing in affluent societies. At puberty, physical characteristics also called secondary sexual characteristics appear. In boys they are: increase in testicular volume and spermache. In females they are menarche and therlache (increase in breast size). Other changes occur in both genders such as growth of pubic and axillary hair. Puberty may be precocious when it is early or may be delayed.
B. CHILD MORBIDITY and MORTALITY
INDICES OF CHILD HEALTH
Immunization coverage, percentage of low birth weight births, and IMR. IMR is affected by both maternal and fetal/infant factors. The maternal factors are maternal age, parity, and social class. The infant factors are gender, birth weight, and multiple births. Males experience a higher IMR than females. Low birth weight babies and twins experience a higher IMR. Child health services in a community can be evaluated by mortality and morbidity surveillance. Surveillance of individual children is by neonatal screening, screening for vision and hearing, dental examinations, growth monitoring, and testing for psychological and social development. Community surveillance consists of health care returns, disease registers, and heath surveys.
CHILD MORBIDITY:
The main causes/manifestations of childhood morbidity are: infectious disease, respiratory conditions, accidents and trauma, disability and handicaps, dental health, psychological problems, behavioral problems (cigarette smoking, sex, alcohol and drug abuse). The main childhood infectious diseases are: diphtheria, pertussis, tetanus, chicken pox, polio, measles, mumps, H influenzae type b, rubella. Measles is increasing once again due to neglect of immunization. Protein energy malnutrition is common in poor urban areas or in situations of civil disturbance. Child abuse, deprivation and other social problems are antecedents to physical morbidity. The causes of brain damage are: infections (rubella, CMV, toxoplasma, herpes), maternal alcohol abuse, malnutrition, and drugs. Dental caries are prevented by regular brushing of teeth, avoiding sugar in the diet, and drinking fluoridized water. Non-accidental injuries are increasing reflecting general increase in stress over families. Accidental injuries: food poisoning, drug poisoning, kerosene ingestion, snake bites, insect bites, near drowning. Accidents can be prevented by education, and environmental changes.
CHILD MORTALITY:
Most deaths in the period 1-4 years are due to accidents and injuries: motor vehicle accidents, drowning, fires and burns, chocking, suffocation, firearms, domestic violence, neglect and abuse. Low SES is a mortality risk at all ages.
INFANT MORTALITY
Child death is highest in the first year due to congenital anomalies, infections, or neoplasms. Primiparous mothers and mothers with advanced age have a higher risk of child mortality in the neonatal period. IMR has been falling due to improvement in socio-economic status, housing, nutrition, immunization, safe water, pasteurized milk, use of antibiotics, good ante-natal care, good post natal care, and technology that makes deliveries safe. The main cause of infant mortality are: prematurity, low birth weight, smoking, alcohol and drugs, poverty, birth defects, and the sudden infant death syndrome (SIDS). IMR can be prevented by good pre-natal care and food supplementation.
C. PREVENTIVE INTERVENTIONS
WINDOW OF OPPORTUNITY :
Childhood is a period in which intervention can have a life-long impact on health habits and health status.
ESSENTIAL CHILD HEALTH SERVICES
The needs of children are: loving care, adequate housing, nutrition, education, and protection from infections, violence, and abuse. Services needed for child health can be summarized using the mnemonic: GOBI-FFF represents major interventions of Growth monitoring, Oral rehydration, Breast feeding, and Immunization and minor interventions of Family spacing, Female education, and Food supplementation. The Expanded Program on Immunization (EPI) was launched in 1974 and covers 6 major childhood diseases: measles, TB, diphtheria, pertussis, and tetanus.
ANTE-NATAL PREVENTIVE SERVICES:
Genetic counseling, family planning, pre-natal care, breast feeding, programs against cigarette smoking, anti- alcohol and drug abuse programs.
POST-NATAL PREVENTIVE SERVICES:
Primary: immunization, dental prophylaxis, infectious disease prophylaxis, accident prevention, prevention of child abuse, health education for the parents and children, health promotion, good nutrition (breast feeding and infant formulas; types and sources of food; utilisation of food: waste, undigested, plate waste; growth monitoring curves, growth disorders; nutritional assessment using skinfold thickness, weight, height, weight for height, marasmus and kwashiokor, nutritional deficiencies due to worms, overnutrition). Injury prevention includes measures about electrocution, drowning, burns, motor vehicle injuries, and poisoning. Covering electrical outlets and insulating electrical wires and appliances prevents electrocution. Drowning is prevented by swimming instruction, fencing pools, grading slopes of man-made lakes and pools, life jackets, lifelines, and use of life guards. Burns are prevented by avoiding use of matches, smoke detectors, flame ratardant clothing and furnishings, and fire escapes. Motor vehicle injury is prevented by use of safety belts and airbags. Poisoning is prevented by use of childproof caps and locked storage.
Secondary: secondary preventive services are also called surveillance and are achieved by screening: physical examination, laboratory tests (PKU, hypothyrioidism, hemoglobinopathis such as SCD and thalassemia), growth monitoring (weight, height, head circumference), testing for vision (refractory errors, congenital cataract, and amblyopia), testing for hearing, dental examination for caries and missing teeth, testing for developmental milestones to identify special needs, testing for behavioral and psychosomatic disorders. Other screening procedures are for: congenital dislocation of the hip, congenital heart disease, undescended testis
Tertiary: services for handicapped children, services for children with special needs, services for neglected or abused children (physical and sexual abuse), services for children who require special/additional attention (low birth weight (LBW), very low birth weight (VLBW), small for gestational age (SGA), maternal and perinatal problems, twins, socially deprived, single parent, nomads, orphans). School health preventive services include health education, anti-smoking programs, sexual counseling of teenagers. The schools are a good site for regular health check-up. Children are reviewed on entry into the school. The school must make sure that the immunization record is complete.
D. SCHOOL HEALTH PROGRAMS
DAYCARE and PRE-SCHOOL PROGRAMS
These programs play a role in child health by developing social skills from interaction, health promotion, and monitoring for diseases and other disabling conditions.
WELL CHILD CARE
Primary prevention is immunization, growth monitoring, and development screening. Secondary prevention is screening for vision and hearing.
SCHOOL HEALTH SERVICES:
The main problems are infection, accidents, and nutrition.
ROLE OF SCHOOL HEALTH IN PRIMARY CARE
The school can play a major role in primary health care because of the compulsory school attendance by all children of the community. School health can play a role in protecting and promoting health. It also can inculcate healthy habits in the future citizens. KAP in childhood can shape health and lifestyle choices of adults. School health services ensure that children are healthy because ill children cannot learn well. In the past school health did not receive the attention it deserved. With the increase of teenage problems the school is being seen once again as an important site for primary health care. Clinics can now be based at school or can be linked to the school.
SCOPE OF THE SCHOOL HEALTH PROGRAM
The school health program has three major components: the health team, the school administration, and the school health policies. School health covers health services, a healthy school environment, health education, guidance and counseling, physical education, food service, social work, psychological services, employee health promotion, and health instruction as part of the school curriculum. Among the services provided by the school health program are: screening and examination (medical, dental, vision, audiological), emergency care for injuries and sudden illness, prevention and control of communicable disease, care for the handicapped, and health advice. A healthy school environment consists of the physical, social, and emotional environments.
SCHOOL HEALTH TEAM
The school health team consists of administrators, food service workers, counseling personnel, maintenance workers, medical personnel (usually a school nurse), social workers, parents, students, and teachers. The school nurse is the coordinator of the team. The school nurse plays the following roles: keeping health records, dispensing medication, training, formulating and implementing school health policies, health counseling, reporting child abuse and child neglect, identifying special needs, and bringing community resources to the school. Teachers play the roles of detecting problems and taking appropriate measures. They also provide health education.
PREVENTION IN SCHOOL HEALTH SERVICES
The school is a site of primary health care. Primary preventive services are health education, safe water supply, food sanitation, fire safety, and immunization. Secondary prevention activities are screening examinations, counseling, and illness care.
SCHOOL HEALTH CURRICULUM
Health can be taught as direct instruction. It can also be correlated with the teaching of other subjects. The contents of health instruction are: community health, consumer health, environmental health, family life, mental and emotional health, injury prevention and safety, nutrition, personal health, prevention and control of disease, control of substance use and abuse.
E. EPIDEMIOLOGY IN CHILD HEALTH
Epidemiology has the following roles in child health: community diagnosis, clinical epidemiology, identification of risk factors, description of the natural history of disease, planning and evaluation, providing normal values. Child care facilities could be a sentinel reporting system for epidemic diseases but this role is not fulfilled because they have no regular system of disease reporting. There are 4 types of disease in child care facilities. Infections that cause disease in both adults and children like shigellosis. Asymptomatic infections like hepatitis A. diseases transmitted by children but cause illness in adults like CMV for pregnant women. Asymptomatic carriers like H influenzae. The common organisms in child care facilities are: bacteria (salmonella, shigella, H influenzae, strep spp), viruses (rhivovirus, enterovirus, and hepatitis A), and parasites like G. lamblia.
10.5.3 ADOLESENT HEALTH CARE
A. DEFINITION and CHARACTERISTICS OF ADOLESCENCE
WHO defines adolescence as ages 10-19 and youth as ages 15-14?. Adolescence is a period of movement from the dependency of childhood to the autonomy of adulthood. It is artificially prolonged in industrial countries due to prolonged schooling and delayed economic independence. Adolescents in consumer societies are targets of music, fashion, and other leisure industries. Adolescents make many mistakes because of the stress of rapid change as well as lack of experience. They want freedom but find it difficult to take responsibility. They are susceptible to peer and mass media pressure. Adolescents mistrust adults and may delay seeking medical care. Adolescent behavior is a cause of stress in the family. Family stresses like divorce impact negatively on adolescents. Adolescence is a period of rapid growth, psychological adjustment, emotional upsets, cognitive change from concrete to abstract thought and youth idealism, as well as social maturation leading to an independent life style. Adolescents do not seek primary health care due to communication difficulties and mistrust of doctors.
B. PSYCHO-SOCIAL PROBLEMS OF ADOLESCENTS
There are no mental disorders unique to adolescents. Maturation stress and role ambiguity lead to many adolescent problems that are sometimes ignored. These include high risk behaviors and life styles like addiction to alcohol and drugs, aggressive behavior, delinquency, anti-social behavior, conflict with parents, aggressive behavior, running away from home/drifting, sexual promiscuity leading to pregnancy and STD, school difficulties, eating problems, depression/anxiety, withdrawal from relationships and being lonely, risk behavior with motorbikes and motorcycles, anorexia and other eating disorders, drug overdose, attempted suicide.
Prevention of adolescent problems: (a) school curricula have changed to address adolescent problems like sex education and drug abuse (b) counselling can protect many adolescents from problems (c) provision of special facilities for medical care. Adolescents hate being seen in the general pediatric units and may not be comfortable in adult units.
OLD AGE
Old age is generally defined to be above 65 years. The young old are aged 65-74 years. The old are aged above 75 years. The oldest old are aged above 85 years.
AGEISM
Ageism is a term used to refer to prejudice against and discrimination of the elderly.
GERONTOLOGY
Gerontology is the science that studies old age from the broadest perspective: chemical, biological, psychological, economic, and historical.
GERIATRICS
Geriatrics is the branch of medicine that deals with structural changes, physiology, diseases, and hygiene of old age.
DEPENDENCY (SUPPORT) RATIO
This is the ratio of the economically productive people aged 20-64 to the economically unproductive or dependent persons aged 0-19 and 65+
LABOR FORCE RATIO
ACTIVITIES OF DAILY LIVING (ADL): The term ADL includes the following activities: bathing, dressing, grooming, using the toilet, transferring into and out of the bed, remaining continent, and feeding one-self. Instrumental ADLs are cooking, cleaning the house, shopping, managing money, and medication.
C. LONG-TERM CARE
Long term care refers to health, personal care, and social services delivered over a sustained period to persons who have lost functional capacity for activities of daily living (ADL). Long-term care can be in the nursing home or home care in the community. Home care has 2 components: home making and home health.