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BIO4503 APPLIED EPIDEMIOLOGY NON-COMMUNICABLE DISEASES 1

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DEFINITION AND RELATED CONCEPTS Def: noncommunicable disease, (NCD) are no-transmissible between persons, medical conditions Chronic vs, acute: NCDs may be chronic or acute Some examples: autoimmune diseases, heart disease, stroke, many cancers, asthma, diabetes, chronic kidney disease, osteoporosis, Alzheimer's disease, cataracts, and so on Risk factors: In opposition to infectious diseases, risk factors dont include an infectious agent but are found in the persons background: LIFESTYLE and ENVIRONMENT

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3 The rise of NCD started after the II WW. Most prevalent leading causes of disease and mortality in developed countries Increased burden in low- and middle- income countries Already leading cause of death in developing countries!: MORTALITY IN 2008: 57 million 1 NCD ASSOCIATED MORTALITY IN 2008: 36 million (2/3 of total) Main NCDs mortality causes: cardiovascular diseases, cancers, diabetes and chronic lung diseases SOME MACRO-FIGURES AND FACTS

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WORLD 10 LEADING CAUSES OF MORTALITY. 2008 4 Deaths [millions] %of deaths Ischaemic heart disease7.2512.8% Stroke and other cerebrovascular disease6.1510.8% Lower respiratory infections3.4661% Chronic obstructive pulmonary disease3.2858% Diarrhoeal diseases2.4643% HIV/AID1.783.1% Trachea, bronchus, lung cancers1.3924% Tuberculosis1.3424% Diabetes mellitus1.2622% Road traffic accidents1.2121%

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5 NCD MORTALITY. 2011

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CRITERIA FOR CAUSATION OF CHRONIC DISEASE. EVANS POSTULATES [I] 6 1.Prevalence of the disease should be significantly higher in those exposed to the hypothesized cause than in controls not so exposed. 2.Exposure to the hypothesized cause should be more frequent among those with the disease than in controls without the disease, when all other risk factors are held constant. 3.Incidence of the disease should be significantly higher in those exposed to the hypothesized cause than in controls not so exposed, as shown by the prospective studies. 4.The disease should follow exposure to the hypothesised causative agent with a normal or long-normal distribution of incubation periods. 5.A spectrum of host responses should follow exposure to the hypothesized agent along a logical biological gradient from mild to severe.

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CRITERIA FOR CAUSATION OF CHRONIC DISEASE. EVANS POSTULATES [II] 7 6. A measurable host response following exposure to the hypothesized cause should have a high probability of appearing in those lacking this before exposure [e.g.: antibody, cancer cell] or should increase in magnitude if present before exposure. This response pattern should occur infrequently in persons not so exposed. 7. Experimental reproduction of the disease should occur more frequently in animals or humans appropriately exposed to the hypothesized cause then in those not so exposed: this exposure may be deliberate in volunteers, experimentally induced in the laboratory, or may represent a regulation of the natural exposure. 8. Elimination or modification of the hypothesized cause should decrease the incidence of the disease [e.g.: attenuation of a virus, removal of tar from cigarettes].

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CRITERIA FOR CAUSATION OF CHRONIC DISEASE. EVANS POSTULATES [III] 8 9. Prevention or modification of the hosts response on exposure to the hypothesized cause should decrease or eliminate the disease [e.g.: immunization, drugs to lower cholesterol, specific lymphocyte transfer factor in cancer] 10. All the relationships and findings should make biological and epidemiological sense. Source: Evans, AS. (1976). Causation and disease. The Henle-Koch postulated revisited. Yale Journal of Biology and Medicine. 49:175-195

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NCD and globalisation NCDs are caused, to a large extent, by four behavioural risk factors that are pervasive aspects of economic transition, rapid urbanization and 21st-century lifestyles: 1.tobacco use, 2.unhealthy diet, 3.insufficient physical activity 4.harmful use of alcohol. Current population-wide initiatives fall short in the global context. E.g.:

1. BEHAVIOURAL FACTORS Prevalence of current daily tobacco smoking among adults. Prevalence of insufficiently active adults defined as: than 25 kg/m2 for overweight or 30kg/m2 for obesity or for adolescents according to the WHO Growth Reference). Prevalence of low weight at birth (< 2.5 kg). Prevalence of raised total cholesterol among adults (total cholesterol 5.0 mmol/l or 190mg/dl). 17

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3 MORTALITY and 4. MORBIDITY All-cause mortality by age, sex and region (urban and rural, or by other administrative areas, as available). Cause-specific mortality data (urban and rural, or other administrative areas, as available). Unconditional probability of death between ages 30 and 70 years from cardiovascular diseases, cancer, diabetes, and chronic respiratory diseases. Cancer incidence data from cancer registries, by type of cancer. 18

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GLOBAL HEALTH STRATEGY Major global political statement on NDC: Global strategy for the prevention and control of non communicable diseases Endorsed by the WHA (2000). Three main objectives: 1.Mapping the epidemic of NCDs and their causes 2.Reducing the main risk factors through health promotion and primary prevention approaches 3.Strengthening health care for people already afflicted with NCDs. 19

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ACTION PLAN FOR THE GLOBAL HEALTH STRATEGY. SIX OBJECTIVES 1 1.To raise the priority accorded to NCD in development work at global and national levels, and to integrate prevention and control of NCDs into policies across all government departments. 2.To establish and strengthen national policies and plans for the prevention and control of NCD 3.To promote interventions to reduce the main shared modifiable risk factors for NCD: tobacco use, unhealthy diets, physical inactivity and harmful use of alcohol 4.To promote research for the prevention and control of NCD 5.To promote partnerships for the prevention and control of NCD 6.To monitor NCD and their determinants and evaluate progress at the national, regional and global levels 20

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FRAMINGHAN HEART STUDY Longitudinal study aiming to better understand the epidemiology of CVD. Started in 1948 [original cohort had not yet developed symptoms of CVD] and the on going follow up is in already its 6 th cohort. 21 SOME MILESTONES: 1960: Cigarette smoking found to increase the risk of heart disease 1967: Physical activity found to reduce the risk of heart disease and obesity to increase the risk of heart disease 1970: High blood pressure found to increase the risk of stroke 1978: Psychosocial factors found to affect heart disease 2002: Lifetime risk of developing high blood pressure in middle-aged adults is 9 in 10. 2002: Obesity is a risk factor for heart failure. 2010: First definitive evidence that occurrence of stroke by age 65 years in a parent increased risk of stroke in offspring by 3-fold

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RECOMMENDED READING WHA 2000. Global strategy for the prevention and control of NCD. Report by the Director-General: A challenge and an opportunity. WHA 53 rd session. WHO (2008) 2008-2013 Action Plan for the Global Strategy for the Prevention and Control of NCD. WHO (2013) World health statistics 2012 WHO (2013) Non communicable diseases. Country profiles 2011 WHO (2003) WHO Framework Convention on Tobacco Control WHO WHO Global Strategy on Diet, Physical Activity and Health 2004 22

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RECOMMENDED READING [cont] Beaglehole R and Yach D (2003) Globalisation and the prevention and control of non-communicable disease: the neglected chronic diseases of adults. The Lancet, Volume 362, Issue 9387, 13 September 2003, p 903-908 Banerjee A. Tracking global funding for the prevention and control of noncommunicable diseases. Bull World Health Organ. At: 2012;90:479479. http://www.who.int/bulletin/volumes/90/7/12-108795/en/ http://www.who.int/bulletin/volumes/90/7/12-108795/en/ Alleyne G. (2011) Whos Afraid of Noncommunicable Diseases? Raising Awareness of the Effects of Noncommunicable Diseases on Global Health. Journal of Health Communication, 16:8293, 2011 23