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Epidemiology of Chronic Non- Communicable Diseases (I) CM-442 Dr Halima Buni Assistance Professor in Community Medicine (MBBch, MSc, PhD)  Learning objectives: 1. To describe the epidemiological transition 2. To define th...

Epidemiology of Chronic Non- Communicable Diseases (I) CM-442 Dr Halima Buni Assistance Professor in Community Medicine (MBBch, MSc, PhD)  Learning objectives: 1. To describe the epidemiological transition 2. To define the problem of non-communicable diseases (NCDs). 3. To recognise the risk factors underlying the most common NCDs 4. To discuss the epidemiology of some NCDs 5. To explain the different preventive levels of NCDs Dr. Halima Changing patterns of disease (epidemiological transition)  The epidemiological transition refers to the general shift from acute infectious and deficiency diseases (characteristic of underdevelopment) to chronic non- communicable diseases (characteristic of modernization).  It was thought that the epidemiological transition is a unidirectional process, beginning when infectious diseases were predominant and ending when non- communicable diseases (NCDs) dominated the causes of death!! Dr. Halima Epidemiological transition-- (cont’d) Dr. Halima Epidemiological transition---(cont’d) BUT in fact it is a continuous transformation process, with some diseases disappearing and others appearing or re-emerging (as a result of antimicrobial resistance). Dr. Halima  Factors involved in the epidemiological transition  Demographic changes:  Increased population density: change in fertility, mortality rates & life expectancy  Changes in risk factors: 1. Biological factors  Alteration in antigenic identity: influenza  Emergence of drug-resistant strains: TB  Dual infection: e.g. AIDS & TB 2. Environmental factors: e.g. exposure to air, water and food pollution 3. Cultural and behavioural factors: changes in lifestyle (urbanization), changes in community relationships, human mobility…  Practices of modern medicine: resulted in an increase in the life expectancy and thus increasing NCDs Dr. Halima  Chronic non-communicable diseases (NCDs)  NCDs have been defined as:  “Comprising all impairments or deviations from normal, which have one or more of the following characteristics":  1. They are permanent  2. They leave residual disability  3. They are caused by non-reversible pathological alteration  4. They require special patient training to look after him/herself  5. They may be expected to require long period of supervision Dr. Halima Dr. Halima Chronic non-communicable diseases (NCDs) Cardiovascular diseases Chronic lung diseases Chronic renal disease Mental diseases (e.g. Alzheimer's disease) Musculoskeletal (e.g. arthritis, osteoporosis) Diabetes Cancers Obesity Permanent results of accidents Degenerative diseases Chronic complications of communicable diseases……etc Dr. Halima  Gaps (difficulties) in Natural History of NCDs  There are many gaps in our knowledge about the natural history of NCDs, which cause difficulties in aetiological investigations and research. These are: 1. Absence of known agent 2. Multifactorial causation 3. Long latent period 4. Indefinite onset Dr. Halima NCDs are characterized by: Uncertain aetiology Multiple risk factors Long latent period Prolonged course of illness Rarely achieve cure (mostly life long) Dr. Halima Size of the problem  The problem of NCDs is on increase, affecting many parts of the world, developed and developing.  The prevalence of NCDs is showing an upward trend in most countries.  It is accounting for about 70-75% of deaths.  Each year, 15 million people die from a NCD between the ages of 30 and 69 years; over 85% of these "premature" deaths occur in low- and middle- income countries.  NCDs cause disability, loss of productivity, family hardship, poverty & economic loss to the country  They show an iceberg phenomenon Dr. Halima  1. Undiagnosed 2. Unaware 3. No Health services 4. Expensive HS 5. Others Dr. Halima Size of the problem: East Mediterranean Region  According to the WHO:  East Mediterranean Region has been identified as a hot spot for NCDs  2.2 million lives lost annually due to NCDs in the Region.  51% of lives lost due to NCDs are premature (< 70 years of age). Dr. Halima Size of the problem-Eastern Mediterranean Region Dr. Halima Size of the problem in Libya Dr. Halima Size of the problem in Libya NCDs mortality in Libya:  NCDs are estimated to account for 78% of total deaths in Libya; CVDs (37%), cancer (13%), RTAs (11%) and diabetes (5%). Dr. Halima Dr. Halima Risk factors of NCDs Dr. Halima  Risk factors of NCDs  NCDs are also called “lifestyle diseases” Dr. Halima Dr. Halima  The main key risk factors of NCDs: 1. Non-modifiable Risk Factors: age, genetics, gender 2. Modifiable Risk Factors: a) Smoking. b) Alcohol consumption. c) Life style changes: Low fruit and vegetable intake, physical inactivity overweight and obesity. d) Stress factors (e.g. person's economic and social conditions). e) Environmental factors (e.g. air and water pollution, destructive weapons). f) Failure or inability to obtain preventive health services (e.g. hypertension control, cancer detection, management of diabetes). Dr. Halima  In Libya  According to STEPS survey (2022-2023) on Libyan adults (age 18-69 years): Dr. Halima General outlines for prevention and control of NCDs Primordial Prevention Prevention of the emergence or development of risk factors Primary Prevention Prevention of the disease occurrence Secondary Prevention Prevention of the development of disease complications Tertiary Prevention Prevention of suffering & functional restriction associated with disabilities Quaternary Prevention Prevention of over/mis-diagnosis & over/mis-treatment Role of PHC physician in prevention and control of NCDs: 1) Health education to improve the life style. 2) Nutritional education to prevent nutrition-related diseases. 3) Identify the high-risk groups for NCDs. 4) Early detection of the diseases by screening high-risk groups. 5) Referral of the identified cases to specialists. 6) Follow up of referred cases to ensure compliance to treatment and healthy behaviour. Epidemiology of Cardiovascular diseases 1. Hypertension 2. IHDs 3. CVAs Dr. Halima  Group of diseases of the heart and vascular system.  The major conditions are ischemic heart diseases (IHDs), hypertension, and cerebrovascular accidents (CVAs).  IHDs and CVAs are the first and second leading cause of death in adult men and women.  IHDs and CVAs make an important contribution to morbidity, mortality and disability worldwide (developed and developing countries). Risk factors of CVDs  1. Genetic and familial tendency, and male gender (non-modifiable)  2. High blood pressure  3. Hyperlipidaemia: cholesterol, LDL or HDL  4. DM  5. Overweight and obesity  6.Physical inactivity and sedentary life  7. Smoking and Alcohol consumption  8. Stress (internal & external) Dr. Halima  The epidemiological burden of CVDs in Libya  According to the last published annual report of the Ministry of Health of Libya (2022):  CVDs are the first leading cause of death in Libya (responsible for 16.9% & 16.4% of deaths in males and females respectively)  IHDs are responsible for 4.1% & 3.7% of deaths in males and females respectively The epidemiological burden of CVDs in Libya: STEPS Survey 2022-2023 1. Hypertension  The BP is the single most useful test for identifying individuals at a high risk of developing CVDs.  140/90 mmHg is the cut-off point above which is considered as hypertensive.  However, there have been multiple proposed cut-off points for defining high BP. Dr. Halima 1. Hypertension: cont’d…  Blood pressure measurement:  Despite of more than 75 years of experience with the measurement of BP, discussion continues about its reliability and wide variability in individual subjects!!!  Sources of errors(variability): 1. Observer errors (bias)= training+ supervision 2. Instrumental errors = standardization 3. Subject errors = readings (mean) Dr. Halima 1. Hypertension: cont’d…  Classification: 1. Primary (Essential) Hypertension: the most prevalent form (90 %), has no clear aetiological factors. 2. Secondary Hypertension: (10%), occurs secondary to some other diseases or abnormalities. Dr. Halima  Magnitude of the problem “Rule of halves”  Hypertension is an “iceberg” disease  It became evident that only about half of the hypertensive subjects in the general population of most developed countries were aware of their condition, only about half of those aware of the problem were being treated & only about half of those treated were considered adequately treated “Rule of halves” Dr. Halima  Magnitude of the problem ”Rule of halves” 1 2 3 4 5 6 7 8 9 Dr. Halima Magnitude of the problem  Incidence: has limited value in HTN (variability & ambiguity)  Prevalence: ranging from 10 to 25% among adults.  High BP levels damage the arteries that supply blood to the heart, brain, kidneys and elsewhere, producing a variety of structural changes.  Therefore, it is a major risk factor of CVDs, stroke, renal failure and other diseases.  Mortality rates are misleading because of underreporting (undiagnosed cases)  In LIBYA: the problem is huge (35.8% diagnosed with HTN & 24.9% on HTN treatment). Dr. Halima Risk factors for Hypertension 1. Non-modifiable risk factors (risk markers):  Age:-BP rises with age in both sexes  Genetic factors:-twin & family studies 2. Modifiable risk factors:  Obesity  High Salt intake  High intake of saturated fat  Physical inactivity  Stress  Alcohol consumption  Others:- e.g. oral contraception Dr. Halima Prevention of Hypertension  1) Primary prevention:  “all measures to reduce the incidence of disease in a population by reducing the risk of onset”  a) Population strategy:-  This approach is directed at the whole population, irrespective of individual risk levels: a. Nutrition (dietary changes) b. Weight reduction c. Exercise promotion d. Behavioural changes e. Health education  b) High risk strategy:  People with one or more risk factors should be intensively educated on the consequences and management of HTN with regular tracking of BP. Dr. Halima Prevention of Hypertension  2) Secondary prevention:  Aims to detect and control high BP in affected individuals through: a. Early case detection & diagnosis b. Proper treatment:- maintain BP below 140/90 mm Hg. c. Ensure patient’s compliance (life-long treatment)  3) Teriary prevention:  Starts with the complication such as; Retinopathy, Renal complications, & Stroke. a. Disability limitation b. Rehabilitation 4) Quaternary prevention:  Prevention of unnecessary use of medications. Dr. Halima  Ischaemic Heart Diseases (IHDs)  IHD is the leading cause of adult mortality and a common cause of chronic disability in many countries.  The prevalence of the disease is increasing all over the world? As population live longer with sustained exposure to the risk factors. The epidemiological profile of IHDs in any country depends on the prevalence of the different risk factors.  Risk factors of IHDs  A. Modifiable behavioural risk factors: 1. Sedentary life style: unhealthy diet and physical inactivity: Sedentary life style increases the risk of IHDs by operating through the other risk factors: obesity, hyperlipidaemia, and diabetes. Regular physical activity lower the BP and aids in smoking cessation  Risk factors of IHDs: cont’d…  A. Modifiable behavioural risk factors: 2. Tobacco smoking: Smoking is a chronic promoter of atherosclerotic lesions Smoking also enhances clotting and platelets adhesions 3. Alcohol consumption: Alcohol consumption increases the risk of hyperlipidaemia It affects the haemostatic factors and platelets aggregation 4. Stress (internal & external)  B. Non-modifiable risk factors: 1. Age:  Atherosclerosis process progresses with age  The incidence of IHDs increases with age (≥ 40 years)  However, heavy smoker young adults could be at risk. 2. Gender:  Before menopause: women are at lower risk for CHDs than men? Could be attributed to the protective effect of oestrogen against atherosclerosis  After menopause: the risk is equal 3. Familial tendency and genetic factors  C. Metabolic/physiological risk factors: 1. Hypertension: is a major risk factor for IHDs 2. Diabetes mellitus:  DM has micro and macro pathological effect on the blood vessels including coronaries  DM causes LDL, TGA and HDL  3. Hyperlipidaemia: LDL (the main atherosclerotic fraction of the cholesterol)  4. Overweight and Obesity: LDL, TGA and HDL Risk factors of IHDs: Libya Risk factors of IHDs: Libya Risk factors of IHDs: Libya  Causes of IHDs  Ischemia of the myocardium results from imbalance between the supplied oxygen by the coronaries and the heart muscle needs.  The causes of the myocardial ischemia are the following:  1. Diminished blood flow in the coronary arteries:  Coronary atherosclerosis, thrombosis, spasm  Coronary embolism, stenosis  3. Increased oxygen demands of the myocardium  Hypertrophied myocardium (Aortic stenosis, hypertension)  Prevention of IHDs 1. Primordial Prevention:  Prevention of the emergence or development of risk factors  Childhood is the target population 2) Primary prevention:  a) Population strategy: This approach is directed at the whole population, irrespective of individual risk levels: Health education to increase awareness about the risk factors and to improve lifestyle (Healthy diet and regular physical activity) Health legislations: e.g., antismoking laws Improve health behaviour (quit smoking)  b) High risk strategy: People with one or more risk factors of IHDs should be intensively educated with regular screening and follow-up.  Prevention of IHDs: cont’d…  3) Secondary prevention: a) Early case detection & diagnosis b) Proper management  4) Tertiary prevention: a) Disability limitation b) Rehabilitation: Medical, social, psychological and vocational rehabilitation 5) Quaternary prevention:  Prevention of unnecessary use of medications.  Cerebrovascular accidents (Stroke)  Defined by the WHO as “Rapidly developed clinical signs of focal (or global) disturbance of cerebral function; lasting more than 24 hours or leading to death, with no apparent cause other than vascular origin”.  Stroke carries a high risk of death. Survivors can experience loss of vision and/ or speech, paralysis, coma and confusion.  The disturbance of cerebral function is caused by 3 morphological abnormalities:  Stenosis,  Occlusion, or  Rupture of the arteries Dr Halima Cerebrovascular accidents (Stroke)  Stroke includes number of syndromes with differing aetiologies, epidemiology, prognosis & treatment: 1. Subarachnoid haemorrhage 2. Cerebral haemorrhage 3. Cerebral thrombosis or embolism 4. Occlusion of pre-cerebral arteries 5. Transcient cerebral ischaemia (of > 24 hours) 6. Ill-defined cardiovascular disease (i.e., the underlying pathology in the brain is not determined) Dr Halima  Stroke ─ size of the problem  It makes an important contribution to morbidity, mortality and disability worldwide (developed and developing countries).  Cerebral thrombosis is usually the most frequent form of stroke encountered in clinical studies followed by haemorrhage.  Morbidity  Stroke incidence rates range from 0.2-2.5 per 1,000 population per year (WHO)  Mortality  Mortality from stroke has been declined in many countries for several years. Dr Halima  Stroke ─ natural history  Our knowledge of the natural history of stroke is far from complete!! 1. Risk factors: a. Hypertension: the main risk factor of cerebral thrombosis & haemorrhage. b. Other factors: cardiac abnormalities, DM, hyperlipidaemia, obesity, smoking,……etc 2. Transcient ischaemic attacks (TIA):  “Are episodes of focal reversible neurological deficit of sudden onset and less than 24hours duration due to micro emboli”.  Show a tendency to recurrence  Are warning sign of stroke Dr Halima  Stroke ─ natural history 3. Host factors: a. Older age b. Gender: usually male. c. Personal history: of associated disease, mostly CVDs and diabetes. In most cases, stroke is an incident in the slowly progressive course of a generalised vascular disease. Dr Halima  Stroke ─ Prevention  Even where advanced diagnostic and therapeutic facilities are available, 60% of all those who suffer a stroke either die or live with some disability.  Thus curative treatment is not a feasible option for reducing deaths from stroke. 1. Primary prevention a. Control hypertension—For every ten people who die of stroke, four could have been saved if their BP had been controlled. b. Early detection & treatment of TIA c. Control diabetes d. Stop smoking. e. Education regarding risk factors of stroke at the population level. Dr Halima  Stroke ─ Prevention 2. Secondary prevention  Early detection of stroke (slurring of speech, weakness in any limb); often, a major attack is preceded by some TIAs. 3. Tertiary prevention  Rehabilitation of residual paralysis by physiotherapy, speech therapy...etc Dr Halima Dr. Halima Buni