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EPIDEMIOLOGICAL CHARACTERIZATION OF NON-COMMUNICABLE DISEASES
Presented at an Interactive Workshop on Essentials of Epidemiology in Public Health at the Department of Social and Preventive Medicine University Malaya Kuala Lumpur Malaysia 19-25 October 2009 by Professor Omar Hasan Kasule Sr MB ChB (MUK), MPH (Harvard), DrPH (Harvard) Professor King Fahad Medical College Riyadh; Professor of Epidemiology and Islamic Medicine Institute of Medicine University Brunei Darussalam, Visiting Professor of Epidemiology University of Malaya
DEFINITIONS
Non-communicable diseases are characterized by a prolonged course, rarity of spontaneous resolution or complete cure, non transmissibility, multi-causality, ignorance of definitive causes, non-specific cause-disease relation, long latency, repeated exposures to the agent, lack of acquired immunity, non-specific diagnostic procedures, and association with lifestyle.
INCIDENCE TRENDS
Their incidence is increasing due to relative decrease of infectious diseases, an older population, industrialization, and better diagnosis.
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. 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. 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. 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.
DISEASE PROCESSES
The main disease processes are neoplasia, inflammation, degeneration, metabolic, and endocrine disturbances. Malignant neoplasms, unlike benign ones, are rapidly growing, poorly differentiated, and invasive. Carcinomas are endodermal and ectodermal, sarcomas are mesodermal, leukemias and lymphomas are from the bone marrow and the immune system. More than 85% of malignant neoplasms are carcinomas. Symptoms and signs due to malignancy may be due to local pressure effects or may be systematic effects (chemicals, hormones, enzymes). The TNM staging system (based on the Tumor bulk, Nodal involvement and Metastasis) is used for treatment and prognosis. Cancer etiology is a multi-factorial interaction of environmental and genetic factors. Cancer may be purely genetic, purely environmental, both genetic and environmental, or spontaneous (independent of both environmental and genetic factors). There are two established cancer causes according to epidemiological and laboratory studies: irradiation (basal cell carcinoma, melanoma, breast cancer, leukemia, and thyroid cancer) and tobacco (lung cancer). The presumptive causes are chemicals (polycyclic hydrocarbons, aromatic amines, nitrosamines, aflatoxin, and alkylating agents), viruses (HTLV, Burkitt’s Lymphoma, Nasopharyngeal carcinoma, hepatocellular carcinoma), diet, alcohol (liver and esophageal cancer), drugs, and genetic effects. Acute inflammation turns into chronic inflammatory disease (chronic ulcers, chronic bronchitis, emphysema, and asthma). Degenerative disease is due to accumulated environmental insults accompanied by age-related impairment of reparative processes. Common degenerative conditions are atherosclerosis, Alzheimer's disease, osteoporosis, and osteoarthritis. Metabolic and endocrine disorders include diabetes mellitus and metabolic disorders of carbohydrate, protein, and lipid metabolism. Insulin-dependent diabetes mellitus (IDDM) is more severe and occurs earlier in life than non-insulin-dependent diabetes (NIDDM). DM is complicated by diabetic retinopathy, cataracts, renal complications, and arterial disease. Traumatic injury occurs in all human activities: at work, at home, and recreation. The most serious traumatic injury is sustained in road traffic accidents (RTA). Psychiatric disorders may have an organic basis or may be innate disturbances of the human psyche or nafs. Schizophrenia and depression are the commonest psychiatric disorders. Dental caries are caused by acid-producing bacteria that lead to progressive decalcification of the dental enamel leaving cavities called dental caries.
PREVENTION
Primary prevention at the community is general (food supplies, education, employment, housing etc) or specific (health promotion, health education, health care, environmental protection directed to air, water, and soil pollution). Secondary prevention at the community level is mass disease screening, case finding, and early treatment. At the individual level prevention can be primary (proper nutrition, health knowledge, exercise, avoiding addictions to alcohol and drugs, safety belts etc) or secondary (diagnosis and treatment). Tertiary prevention is rehabilitation. The barrier to prevention is inability to change human behavior since most non-communicable diseases can be prevented by behavioral and lifestyle change.
Key Words And Terms: Chronic Diseases, Non-Communicable Disease, Degenerative Disease, Multiple Causes, Prolonged Course, Spontaneous Resolution, Rare Complete Cure, Non Transmissibility, Specific Cause-Disease Relation, Long Latency, Ecological Transition, Demographic Transition, Epidemiologic Transition, 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,
RISK FACTORS
Presented at an Interactive Workshop on Essentials of Epidemiology in Public Health at the Department of Social and Preventive Medicine University Malaya Kuala Lumpur Malaysia 19-25 October 2009 by Professor Omar Hasan Kasule Sr MB ChB (MUK), MPH (Harvard), DrPH (Harvard) Professor King Fahad Medical College Riyadh; Professor of Epidemiology and Islamic Medicine Institute of Medicine University Brunei Darussalam, Visiting Professor of Epidemiology University of Malaya
NUTRITION:
Under-nutrition is more likely in the economically underdeveloped countries. Over-nutrition is more common in the economically developed and industrialized countries. Qualitative malnutrition is specific malnutrition and involves selected micronutrients. Quantitative malnutrition is either excess total intake or reduced total intake. Generally malnutrition is an underlying factor in all diseases due to its effect on the immune system. Some diseases are specifically related to malnutrition such as 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. 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. Esophageal cancer is associated with preservatives, dietary deficiency, alcohol, and mycotoxins. Stomach cancer is associated with dietary intake of nitrosamines and fats. Colon cancer is associated with diets that have high protein, high fat, and low fiber contents. Liver cirrhosis and liver cancer are associated with alcohol intake, and aflatoxins in the diet.
ALCOHOL:
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. 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 apnoea, chronic obstructive lung disease, pneumonia, lung abcess, pulmonary tuberculosis, laryngeal carcinoma, and carcinoma of the lung. 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. 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.
TOBACCO
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. 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. 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. Smoking behavior can be modified by: knowledge of the health risks, attitude to smoking, cigarette advertising, cost of cigarettes, peer influence, and legislation.
PHYSICAL INACTIVITY:
Physical inactivity is related to the following diseases: hypertension, osteoporosis, and mental health. Beliefs, motivation, self-discipline, availability of facilities for exercise, and peer support affect the level of physical activity undertaken by a person.
ENVIRONMENTAL FACTORS:
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.
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.
CANCER
Presented at an Interactive Workshop on Essentials of Epidemiology in Public Health at the Department of Social and Preventive Medicine University Malaya Kuala Lumpur Malaysia 19-25 October 2009 by Professor Omar Hasan Kasule Sr MB ChB (MUK), MPH (Harvard), DrPH (Harvard) Professor King Fahad Medical College Riyadh; Professor of Epidemiology and Islamic Medicine Institute of Medicine University Brunei Darussalam, Visiting Professor of Epidemiology University of Malaya
INCIDENCE AND MORTALITY
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. 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. 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. 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. 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.
CANCER SITES
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. Breast cancer is mainly a disease of females. Incidence rises with age. Cervical cancer is more common in less developed countries. Its incidence rises with age. The incidence of colon cancer is falling in the US and the risk is equal for men and women. The incidence of esophageal cancer is high in Central Asia, the Far East, and the Transkei. There is an upward trend. Males are affected more than females. The incidence of stomach cancer is higher in males but is declining. The incidence of liver cancer is high in Africa and the Far East but rare in Europe and USA. Male incidence is higher if liver cancer is associated with cirrhosis. If not associated with cirrhosis there is no gender difference. The peak incidence in the low incidence areas of Europe and the US is 50-70. The peak incidence in the high risk areas of Africa is 20-30yr. The incidence of pancreatic cancer is rising all over the world and increases with age. Africans and Maoris have high incidences. Nasopharyngeal carcinoma is high among the Chinese. Oral cancer occurs more often in less developed countries. It affects the elderly and males more.
RISK FACTORS
Cancer risk is determined by heritage or the environment or both. About 20-25% of malignancies are spontaneous. Some cancers like familial retinoblastoma and familial breast cancer are determined by heritage with no environmental effect at all. Environmental determinants are involved in lung cancer (cigarette smoke) and leukemia (radiation). In some cases genetic susceptibility enhances the effect of environmental agents. Some cancers like hepatocellular carcinoma have an infectious etiology (RBV). Epidemiological and experimental approaches are used in investigating cancer determinants. The established environmental determinants of cancer are: ultraviolet radiation, ionizing radiation, tobacco, alcohol, chemicals, and biological agents. The presumptive environmental carcinogens are chemical pollutants, electromagnetic fields, and diet. Suspected carcinogens are electromagnetic fields and Aspergillus flavus (in liver cancer), and fat (in colon cancer).
CANCER PREVENTION
The strategy of primary prevention is to avoid exposure to known carcinogens. A conservative attitude is taken by assuming that there is no threshold exposure. The period of exposure is more important than the dose of the carcinogen. It is more profitable to attack synergistic relations among co-carcinogens than 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 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.
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, Mutagenicity, 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
DISEASES BY ORGAN SYSTEMS
Presented at an Interactive Workshop on Essentials of Epidemiology in Public Health at the Department of Social and Preventive Medicine University Malaya Kuala Lumpur Malaysia 19-25 October 2009 by Professor Omar Hasan Kasule Sr MB ChB (MUK), MPH (Harvard), DrPH (Harvard) Professor King Fahad Medical College Riyadh; Professor of Epidemiology and Islamic Medicine Institute of Medicine University Brunei Darussalam, Visiting Professor of Epidemiology University of Malaya
CARDIOVASCULAR AND RESPIRATORY DISORDERS
Cardio-vascular diseases (CVD) are coronary Heart Disease (CHD) / ischemic heart disease (IHD), stroke, and rheumatic heart disease (RHD). Heart diseases are hypertensive heart disease (HT), congenital heart disease, and infective heart disease. Myocardial infarction (MI) in IHD has high mortality. HT is complicated by cerebral hemorrhage, heart failure, and renal failure. RHD is still an important in Less Developed Countries (LDC). The incidence Rate (IR) of CVD is rising due to an older population and spread of the industrial/western lifestyle. IHD/CHD, more common in males with IR rising with age, has risk factors (RFs) of cigarette smoking, HT, cholesterol and other lipids. Essential HT has no known RF. The RFs of stroke are HT, cigarette smoking, alcohol, obesity, high serum cholesterol, and atrial fibrillation. The 1ry prevention of CVD is by dietary change (low fat, low calories, and low sodium), management of HT, physical activity, abstention from alcohol and smoking. The 2ry prevention of CVD is screening for RFs and management of HT, management of CHD (drugs or surgery), and prompt treatment of MI, use of warfarin and aspirin for stroke. Tertiary prevention applies mostly to stroke victims who require long periods of rehabilitation.
Chronic Non-specific Respiratory Disease (CNRD) comprises chronic bronchitis, emphysema, and asthma. Asthma is a worldwide condition with rising incidence but low mortality. IR of Chronic bronchitis & emphysema is higher in males and is increasing. Pneumoconioses are occupational lung disease. The RFs of CNRD are cigarette smoking and air pollution.
PSYCHIATRIC AND NEUROLOGICAL DISORDERS
The main psychiatric disorders are drug dependency, alcohol abuse, schizophrenia, anxiety, depression, suicide and parasuicide, eating disorders, and mental handicap.
Drug dependency is an epidemic. Commonly abused drugs are marijuana, narcotics, and cocaine. RF of drug abuse are genetic or environmental (home, family, society, low SES, social isolation, poor living conditions, depression, low self-esteem, and psychological distress). 1ry prevention of drug abuse is by education (at home, school, and the community), decreasing availability, and arrest of drug pushers. 2ry is by drug education to reduce demand and effective drug treatment. 3ry prevention is further treatment and aftercare.
Schizophrenia prevalence of 1.1 - 5.1/1000 in adults is uniform world-wide being higher in DC, peaking in the mid-20s, and with F>M. RFs of mental disorders can be congenital, physical or physiological impairment, psychological causes, and idiopathic. 1ry prevention of mental disease is by decreasing/avoiding stressful events, treatment of physical disease, control drug addiction, identification of at risk groups. 2ry prevention is by screening in PHC, education, therapy (biochemical, psychological, or behavioral), and follow-up of high-risk groups to prevent relapse. Prolonged drug maintenance leads to a normal life.
Mental retardation presents as intellectual impairment (low IQ), learning disability, and specific disabilities or handicaps. Its RFs are chromosomal (Down’s, sex chromosome and other autosomal disorders), neurological (PKU, galactosemia, Tay-Sachs, Hurler’s), antenatal factors (iodine deficiency, Rh incompatibility, alcohol, and drugs), perinatal factors (trauma, hypoxia, hypoglycemia, and cerebral thrombosis), postnatal disorders (trauma, infection, chemical agents, and nutritional or metabolic disorders). 1ry prevention of mental retardation is health promotion and specific protection (pre-marital screening and genetic counseling, immunization, and socio-economic development). 2ry prevention is early detection (pre-natal and neonatal screenings), treatment to limit disability and start rehabilitation. Tertiary prevention limits severity and complications.
Important neurological disorders are migraine headache, stroke, back pain, epilepsy, Parkinson’s disease, peripheral nerve disorders, dementia, Alzheimer’s disease, multiple sclerosis, and cerebral palsy. Migraine is familial with peak IR at 40 years and higher female risk. IR of backache increases with age to peak at 55-64 years and is higher among nurses, drivers, manual workers, miners, and lumber workers. IR of epilepsy has no gender difference and is highest in the young and the elderly >70 years. IR of Parkinson’s disease increases with age, is higher in males, is highest in Caucasians, intermediate in Africans, and lowest in Asians. IR of senile dementia is increasing in the elderly. IR of Alzheimer's disease rises with age. The IR of Multiple sclerosis is higher IR in cold climates and females, increases with age to peak at 30 yr, but is rare in childhood and above 50 yr. RFs of neurological conditions differ: migraine (familial), backache (age, occupation, psychosis and stress), epilepsy (perinatal infections, low birth weight, maternal malnutrition, maternal anemia, preterm delivery, aged motherhood, cerebral palsy, febrile seizures, head injuries, parasitic infections such as trypanosomiasis, toxic agents such as lead or alcohol, or heredity), Alzheimer’s disease (age and female gender), multiple sclerosis (childhood infection). Prevention for each condition is migraine attacks (avoiding the triggers and use of analgesics), back ache (education on proper spine positions during lifting heavy loads, use of lumbar supports, and better ergonomic design), epilepsy (treatment of infections, good antenatal and perinatal care, and prevention of head injuries. Parkinsons’s disease and multiple sclerosis have no definite preventive measures.
GASTRO-INTESTINAL, GENITO-URINAL, AND METABOLIC DISORDERS
Oral disorders: The main oral disorders are: dental caries, periodontal disease, cleft lip and cleft palate, and oral malignancies. Epidemiological indices of oral disease are DMF (D = number of decayed teeth, M= number of missing teeth, F= number of filled teeth), OHI (Oral Hygiene Index), and PI (Plaque Index). OHI and 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). IR of dental caries is rising. IR of dental caries is higher in DC. IR of periodontal disease is higher in LDC and the low SES, is higher in rural areas, is higher in males, severity increases with age, and is associated with poor oral hygiene. RFs for dental caries are: low salivary flow, diet (refined food with high sugar content). The RF for periodontal disease is poor oral hygiene. The RFs for cleft lip are 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. Dental caries are prevented by use of fluoride, occlusal sealants, good oral hygiene involving (plaque removal, regular brushing, and flossing), dietary modifications (decreasing fermentable carbohydrates, increasing fiber, and adequate phosphorus and calcium). 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.
Alimentary diseases are liver diseases (acute hepatitis, cirrhosis, hepatocellular carcinoma, and Raye’s syndrome), pancreatic disease (acute and chronic pancreatitis); peptic ulceration (esophagus, stomach, and the duodenum); inflammatory bowel disease (Crohn’s disease and ulcerative colitis); cholelithiasis; appendicitis, diverticular disease of the colon. RFs of liver cirrhosis are alcohol and viral infection. RFs of pancreatitis are alcohol, gallstones, nutrition, drugs, high dietary fat and protein. A western diet is a RF for Crohn’s disease and ulcerative colitis. Obesity, high parity, oral contraceptives, and smoking are RFs for cholelithiasis.
The major metabolic diseases are diabetes mellitus (DM) and iodine deficiency. The IR of DM is increasing. NIDDM is more common than IDDM. IR of IDDM peaks at 12 yr but IR of NIDDM peaks over 40yr. The complications of DM are microvascular (retinopathy, nephropathy, and neuropathy) or macrovascular (atherosclerosis). IDDM is mainly genetic. NIDDM is mainly environmental related to lifestyle physical inactivity, obesity, fat distribution, and poor nutrition). Hypothyroidism is an iodine deficiency disorder affecting fetuses (stillbirth, abortion, congenital anomalies, and brain damage, neonates (neonatal goiter and brain damage), children (goiter, loss of energy, impaired school performance, retarded physical growth), and adults (goiter, loss of energy, and impaired mental functioning). Preventive possibilities for endocrine and metabolic disorders are limited. 1ry prevention is DM is by Lifestyle changes (diet, exercise, smoking, and alcohol intake). Mass screening for DM is not feasible but control of blood sugar reduces both microvascular and macrovascular complications. Neonatal iodine screening is goiter-endemic areas and iodine deficiency is corrected by using iodized salt, iodized milk, or injection of iodized oil.
TRAUMATIC and MUSCULOSKELETAL DISORDERS
Traumatic injury is unintentional (motor vehicle crashes, falls, fires, drowning, injury at the workplace, and natural hazards such as floods, tornadoes, earthquakes, and hurricanes) or intentional (suicide, suicide attempts, assaults, homicide, elder abuse, child abuse, sexual assault, spousal violence, and child sexual abuse, school violence). IR of injuries is increasing. Children <4 years and the elderly are at higher risk. RFs intentional injury are gender (M>F), environmental (alcohol and drug abuse, violence early in life, media violence, peer/community violence, poverty, hopelessness, unemployment, low self esteem, and availability of firearms), or psychological (stress, personality, alcohol and drug abuse). Road Traffic accidents (RTA) are increasing due to more motorized transport. 1ry prevention of traumatic injury is by education (driver education), regulation (speed limits, drunk driving laws, seatbelt laws, gun control), automatic protection (seat belts and other restraints, tachometers for speed, air bags), engineering controls (road engineering, road and vehicle lighting, improved brakes, increasing vehicle stability, removal of rigid and flammable structures from vehicle interior, separation of heavy and light vehicles on the road), SES improvement, and litigation. 2ry prevention is by early identification and screening, medical intervention (CPR training, and acute medical care), behavior modification, early school intervention, counseling, family support, and risk factor identification. Tertiary prevention is jail/prison for criminals, and rehabilitation for victims (physical, occupational, and speech therapy).
Common musculo-skeletal disorders are rheumatoid arthritis (RA), osteoarthritis (OA), osteoporosis, intervertebral disk disorders, neck and back disorders. IR of RA is highest in Europe and America, is increasing, and is higher in females. IR of OA rises with age, and is low below 50 years. Osteoporosis is rare below the age of 50, F>M, and IR increases with age. It is associated with fractures of the hip, spine, and forearm. It is due menopause, senility, is secondary to acromegaly, hypothyroidism, and the Cushing syndrome. RA may have an autoimmune cause. Knee injury and stress injury due to obesity are RFs for OA. Prevention of OA is by weight reduction and arthroplasty. Low back pain is prevented by education and exercises.
Impairment is any loss or abnormality of psychological, physiological, or anatomical structure or function. Impairment turns into a disability when there is reduction of normal activity. A handicap is a disadvantage resulting from an impairment or a disability that limits or prevents fulfillment of normal roles.
CONNECTIVE TISSUE DISORDERS
Hematological disorders of epidemiological importance are anemia, thalassemia, sickle cell disease (SCD), and leukemias. RFs of anemia are pregnancy, lactation, and low SES. Sickle cell disease (SCD) is genetic being 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.
Acute myeloid leukemia (AML) is commonest in women, young adults, and the elderly. Chronic lymphoid leukemia is rare in children and young adults but its IR rises with age reaching a peak in mid-life, and is higher in males. IR of Hodgkin’s disease (HD) has 2 peaks in early adulthood and in old age. Non-Hodgkin’s lymphoma (NHL) peaks in the pre-adolescents and the elderly. Multiple myeloma (MM) is predominantly in the elderly. Hemophilia A affects males but is transmitted by females.
Skin disease: Psoriasis incidence peaks at puberty and menopause. Ichthyosis (scaly skin) incidence peaks in infancy and childhood. Acne vulgaris peak at puberty. Chronic ulcers. Vitiligo, with onset before 20 yr. Skin neoplasms are squamous cell, carcinoma basal cell carcinoma, and melanoma.
AGE-RELATED CONDITIONS
Presented at an Interactive Workshop on Essentials of Epidemiology in Public Health at the Department of Social and Preventive Medicine University Malaya Kuala Lumpur Malaysia 19-25 October 2009 by Professor Omar Hasan Kasule Sr MB ChB (MUK), MPH (Harvard), DrPH (Harvard) Professor King Fahad Medical College Riyadh; Professor of Epidemiology and Islamic Medicine Institute of Medicine University Brunei Darussalam, Visiting Professor of Epidemiology University of Malaya
MATERNAL DISORDERS
Trends are towards smaller families, higher divorce, reduced fertility, early sexual experience, and late marriage. Reproductive epidemiology studies infertility, abortion, pregnancy, birth, birth defects, still births, maternal and infant mortality. Risk factors of poor pregnancy and infant outcomes are poor pre-natal care, socio-demographic (age below 17 and above 34, low SES, single motherhood, and education), medical (heart disease, diabetes, sickle cell anemia, thyroid disease, hepatitis, asthma, tuberculosis, hypertension, and malignancy), pregnancy-related (uterine anomalies, cervical incompetence, anemia, bleeding, Rh isoimmunization, multiple gestation, pre-mature membrane rupture, pre-ecclampsia and ecclampsia, placenta previa, deep venous thrombosis, and infections), bad obstetric history (pre-term or low birth delivery, high parity, short birth interval, eclampsia), life style (smoking, alcohol, drug abuse, malnutrition, stress, and lack of social support), environmental (toxic and occupational exposures, strenous work in pregnancy). Maternal mortality is number of deaths per 100,000 live births in a given year due to complications of pregnancy, child birth, and the puerperium. Its antecedents are ectopic pregnancy, spontaneous abortion, hemorrhage (intra-partum and post-partum), toxemia, and puerperal infections. Maternal and infant mortality have been falling in almost all countries due to improved socio-economic conditions and better medical services. Primary preventive services are counseling about nutrition and behavior, family planning, ante-natal care, delivery services, post-natal care, training in mothercraft skills (parenting, breast-feeding, and cooking), protection from teratogens. Secondary preventive services are screening (syphilis, HIV, and Rh) and treatment. Tertiary preventive services are controlling existing conditions such as HT, DM, and toxemia of pregnancy. Social welfare of mothers includes maternity leave (paid and unpaid), daycare, and protection from (paid and unpaid).
CHILDHOOD DISORDERS
Indices of child health are immunization coverage, percentage of low birth weight births, and IMR. IMR is affected by maternal factors (maternal age, parity, and social class) and fetal/infant factors (gender, birth weight, and multiple births). The causes 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). Child abuse, deprivation and other social problems are antecedents to physical morbidity. IMR is highest in the first year and is due to congenital anomalies, infections, or neoplasms. It is caused by prematurity, low birth weight, maternal smoking, alcohol and drugs, poverty, birth defects, and the sudden infant death syndrome (SIDS). It is prevented by good pre-natal care and food supplementation. Services/interventions needed for child health are summarized as GOBI-FFF that represents major interventions (Growth monitoring, Oral rehydration, Breast feeding, and Immunization) and minor interventions (Family spacing, Female education, and Food supplementation). The Expanded Program on Immunization (EPI) was launched in 1974 to covers 6 major childhood diseases: measles, TB, diphtheria, pertussis, and tetanus. Preventive services can be ante-natal (genetic counseling, family planning, pre-natal care, breast feeding, smoking cessation, alcohol and drug control), primary post-natal (immunization, dental prophylaxis, infectious disease prophylaxis, accident prevention, child abuse prevention, health education for the parents and children, health promotion, and good nutrition.. Secondary post-natal preventive services are screening: physical examination, laboratory tests (PKU, hypothyrioidism, hemoglobinopathies eg SCD and thalassemia), growth monitoring (weight, height, and head circumference), vision (refraction, cataract, and amblyopia), hearing, dental (caries and missing teeth), developmental milestones, behavioral and psychosomatic disorders. Tertiary preventive services are for handicapped, special needs (speech disorders, hyperkinetic behavior, delinquency, and physical disabilities), neglected or abused children; low birth weight (LBW), very low birth weight (VLBW), and small for gestational age (SGA) children; twins; nomads, and orphans. School health services provide screening, health promotion, and health protection.
ADOLESCENT DISORDERS
DISORDERS OF THE ELDERLY