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Epidemiologic transition, global burden of disease, and emergence of NCDs Pascal Bovet, MD, MPH University Institute of Social and Preventive Medicine (IUMSP), Lausanne Consultant for NCD, Ministry of Health, Seychelles 7 th WHO-IUMSP International Seminar on the Public Health Aspects of NCDs Lausanne-Geneva, 3 -7 June 2013
Outline • The health transition • The driving engines: • Demographic transition • Epidemiological transition • Global burden • Trends of diseases • Fraction of the burden attributable to avoidable risk factors • Conclusions
Objectives • Describe the principles and different stages of the epidemiological transition • Describe the principles and main overall results of global burden of disease project What the participant will have achieved as a result of participating in the session • Be able to articulate the epidemiological and demographic engines driving the epidemiological transition • Be able to articulate the magnitude of the burden of disease according to time, regions, broad disease categories and main risk factors
The epidemiologic transition (health transition) • Described in the 1970 s (Omran, later Olshansky, Ault) – Relationship between socioeconomic development and health – Shift from communicable diseases and nutritional deficiencies to NCDs – Classification of 4 stages to relate socioeconomic and disease patterns • Provides a framework to understanding current and future health patterns and needs – Relevance for LICs experiencing early stages of health transition – Model for health planning, particularly where available data are scarce Omran AR. The epidemiologic transition: a key of the epidemiology of population change. Milbank Mem Fund Q 1971; 49: 509 -538 Olshansky & Ault. The fourth stage of epidemiologic transition: the age of delayed degenerative diseases. Milbank Mem Fund Q 1986; 64: 355 -91
The 4 stages of the health transition Stages 1* 2* Socio. Life economic expecdevelopment tancy ~30 + Age of pestilence (LIC, rural SSA) (infection) and famine 30 -50 Age of receding++ (LIC-MIC) pandemics Main characteristics Broad disease categories (proportionate mortality) Infectious diseases CVD: 5 -10% of all † Nutritional deficiencies Related to nutrition/infection: RHD; cardiomyopathies) Improved sanitation : CVD: 10 -35% Hypertensive heart disease, infections, diet stroke, sequels of RHD (salt), aging 3* 50 -55 Age of degen. +++ and man-made (MIC, countries in transition) diseases aging, lifestyles related to high SES: sat fats, sugar, Inactivity, smoking) 4** Age of delayed ++++ degenerative (western countries) diseases risk behaviors CVD <50% (delayed stroke an IHD, CHD, aging population in the population (prevention and health & better treatment new promotion) and treatments >70 CVD: 35 -65% Obesity, dyslipidemias, HBP, ® IHD, stroke, often at early age Omran. The epidemiologic transition. Millbank Mem Fund Q 1971 ; 49 : 509 -38 Olshansky & Ault. The 4 th stage of the epidemiological transition. Millbank Mem Fund Q 1986 ; 64 : 355 -91
Main engines of the health transition: demographic transition and epidemiologic transition Socioeconomic, public nutrition mortality economic social & sanitation ( infant mortality) development environment , housing, technology followed by Industrializat al changes health for health fertility ion & care urbanization wealth & per cap. + Heath care transition income, changes in environm. favoring adoption of increasi old risk behaviors NCD ng and persons at levels of RF: infectious aging risk of fat, calories, tobacco, diseases populatio developing sedentary habits ns NCDs
Demographic transition (Mauritius, 1890 -1990): decrease of mortality followed by decrease of fertility
Developed Men 1960 Developing 2000 2040 Women Demographic transition: ageing and increasing populations in LMICs Note: “Population bonanza” before large proportion of population gets old (and large total NCD burden) Kinsella K & Wan H. U. S. An Aging World. Census Bureau, International Population Reports, P 95/09 -1: 2008. Washington, DC, 2009.
Changing socio-economic structures underlie large changes in behaviors (nutrition transition) • Shift from a preindustrial agrarian economy to industrialization – Less active physical activity for individuals – Higher availability of cheap processed foods (high fat, high carb. ) – More varied foods available to all • Profound changes in household technology (leads to less PA) – Food availability: canning, refrigeration, freezing, radiation, packaging – Food preparation: fossil fuels, electricity, appliances (cooker, mixers) – More varied foods at home • Dramatic shift in leisure activities for adults and children – Time spent for viewing television (sedentary habits) – Images/marketing brought to each household (alters consumption) – More time for leisure PA Adapted from Popkin B. The nutrition transition and obesity in the developing world. Nutr J 1991; 131: 871 -73
Globalization favors lifestyle transition (good and bad changes) • Trade liberalization (of world markets) and urbanization – Nutrition transition: fats, sugar (‘coca-colanisation’), ↓ complex carbohydrates – Supply larger than demand fuels competition & promotion (large portions, “all you can eat”, etc), reduces cost of $/calorie (fats, sugars): favors consumption – tobacco – But also allows for more varied foods (5 th stage of health transition) • Information & communication technologies – Global advertising & promotion of unhealthy lifestyles – But also allows promotion of potentially healthy behaviors • Urbanization and accelerated migration of populations – Acculturation facilitates adoption of unhealthy lifestyles – But increased incomes allow for potentially healthy activities
From traditional to modern food marketing. .
From ancient to modern work ….
From traditional to modern transportation. .
Stages of nutrition transition: development does not equate to ineluctable worsening of lifestyles Popkin et al. The nutrition transition: worldwide obesity dynamics and their determinants. IJO 2004; 28, S 2–S 9.
Proportion of the world population living in urban areas HIC MIC LIC Rydin Y et al. Shaping cities for health: complexity and the planning of urban environments in the 21 st century. Lancet 2012
A model of the health transition accounting for mortality rates of diseases and broad cause of NCD
Emergence and decline of CVD: different stages of health transition along different development stages Rates of CVD:
Share of DALYs by main disease causes and region (2002) Mathers et al 2003
Health transition: changes of mortality in Latin America, 1970 - 1995 infectious cancer CVD perinatal injury Guatemala Mexico other Uauy et al. J Nutr 2001 Chile Uruguay
Since NCDs are largely related to behaviors, social determinants of health are highly relevant for NCDs • Greatest share of health problems are attributable to social conditions in which people live and work • Focus on “causes of the causes”, particularly relevant for NCD (“lifestyle”): need for policies to protect health across all sectors (“health in all policies”) • Health transition varies by country, region, and local settings The Final Report of the WHO Commission on Social Determinants of Health. 28 August 2008
A tale of two cities It is not urbanization itself, it is the kind of urbanization and/or city
What is global burden of diseases (GBD)? • Started as collaboration between WHO, WB and Harvard in the 1980 s • A standardized framework integrating all available epidemiological information on morbidity and mortality • All morbidity and mortality estimates are made internally consistent (e. g. all deaths add to 100%) using condition-specific epidemiology • Provides a quantitative assessment of the distribution of both diseases and their risk factors in populations • Common single metric to quantify health status (DALY) Comparable estimates across causes Consistent measure for use with intervention analyses • Allows to assess to which extent disease and risk for diseases could be avoided in different populations/regions
Disability adjusted life year (DALY) is used to asses the burden of disease http: //en. wikipedia. org/wiki/Disability-adjusted_life_year 23
Mortality: global projections, 2004 -2030 30 Intentional injuries Other unintentional Road traffic accidents Deaths (millions) 25 20 Other NCD 15 Cancers 10 CVD Mat//peri/nutritional 5 Other infectious HIV, TB, malaria 0 2004 2015 2030 High-income countries 2004 2015 2030 Middle-income countries 2004 2015 2030 Low-income countries
Contribution of a risk factors to disease burden World Health Report, WHO, 2002
Burden of diseases: web site of the Institute for Health Metrics and Evaluation (IHME) www. healthmetricsandevaluation. org/gbd
Global death ranks for top 25 causes in 1990 and 2010, and the percentage change between 1990 and 2010 This figure is available online at http: //healthmetricsandevaluation. org/gbd/visualizations/regional
Ranking of leading risk factors in 1990 & 2010, and % change (world) Lim SS et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990– 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380: 2224– 60
Ranking of leading causes of DALYS by regions, 2010 Murray C et al. Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990– 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380: 2197– 223.
Risk factors ranked by attributable burden of disease & by country, 2010 Lim SS et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990– 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380: 2224– 60
Screenshot of an output from “GBD Compare” showing a treemap of YLLs in India in 2010 Murray et al. Lancet 2013
Screenshot of an output of “GBD Compare” showing the % of DALYs attributable to tobacco by country in 2010 Murray et al. Lancet 2013
Projected deaths in Pakistan in 2010 and 2025 by age and cause Jafar TH et al. Non-communicable diseases and injuries in Pakistan: strategic priorities. Lancet 2013
Burden of disease attributable to 20 leading risk factors expressed as % of total DALYs, UK, 2010 Murray et al. Lancet 2013
Levels of BMI, SBP, and cholesterol vary according to GDP Males Females Ezzati E et al. Rethinking the ‘‘diseases of affluence’’ paradigm: Global patterns of nutritional risks in relation to economic development. PLo. S 2005; 2; e 133
BMI Secular trends in BMI, BP and TC in LMIC and HIC (GBD) Mean BP Mean cholesterol Farzadfar F et al. Trends in serum total cholesterol since 1980: systematic analysis of health examination surveys and epidemiological studies with 321 country-years and 3. 0 million participants. Lancet 2011; 377: 578 -86. Finucane MM et al. Trends in BMI since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 countryyears and 9. 1 million participants. Lancet 2011; 377: 557 -67. Danaei G et al. Trends in systolic BP since 1980: systematic analysis of health examination surveys and epidemiological studies with 786 countryyears and 5. 4 million participants. Lancet 2011; 377: 568 -77. Editorial: Annand & Yusuf. Stemming the global tsunami of cardiovascular disease. Lancet 2011 1980 1990 2008
49% decrease in age-adjusted mortality for stroke and MI between 1989 and 2010 in Seychelles Stringhini S et al. Declining stroke and myocardial infarction mortality between 1989 and 2010 in a country of the African region. Stroke 2012; 43: 2283 -88.
Trends in number of total and CVD deaths, Seychelles 1990 -2010 (vital statistics) Stringhini S et al. Declining stroke and myocardial infarction mortality between 1989 and 2010 in a country of the African region. Stroke 2012; 43: 2283 -88.
Total number of stroke deaths if mortality remains unchanged or decrease by 3% in an aging population, Seychelles, 1989 -201 - Age-specific stroke death rates in 1991 (mean 1989 -1991) unchanged up to 2010: 2596 in 20 yrs - Age-specific stroke death rates decreased by 3% every year from 1991 to 2010 (20 years) - Actual age distribution of population every year - Stroke deaths avoided by annual 3% decrease vs. no decrease in 20 years =(2596 -1820)/2596= -30% Stroke, 2012
What will be driving NCD trends in in LMICs, 2004 -2030 ? Roles of epidemiological changes or aging changes Abegunde et al. Lancet, 2007
Health transition: a tool for anticipating and planning health response ! I skate where the puck will be Wayne Gretsky « Greatest hockey player of all time »
Jiaquan Xu J et al, Division of Vital Statistics Deaths: Final Data for 2007 National Vital Statistics Reports. Vol 58, Nb 19 May 2010
The health transition and GBD: some conclusions • Link between demographic/social changes and disease patterns • Patterns vary by region, country, region and within settings • Double burden of disease in many countries • Transition to NCDs is inevitable as populations are aging • Patterns of NCD will change over time (from CVD -> Cancer -> Neuro) • Need to reduce risk factors (and rates of NCDs) faster than aging of populations to contain (an eventually reduce) the total numbers of NCD deaths • Transition model provides rationale for prospective planning, also when epidemiological data are not available locally or NCDs are not yet preponderant • Good news : later transition stages predicts reduced rates of the “big four” NCDs (conditional to appropriate policy and health care response)