page_title: Epidemiological transition
section_title: Other perspectives
hierarchical_section_title: Epidemiological transition / Other perspectives
caption_attribution_description: English: Leading causes of DALYs and percentage change between 1990-2013, Zimbabwe
context_page_description: In demography and medical geography, epidemiological transition is a theory which "describes changing population patterns in terms of fertility, life expectancy, mortality, and leading causes of death." For example, a phase of development marked by a sudden increase in population growth rates brought by improved food security and innovations in public health and medicine, can be followed by a re-leveling of population growth due to subsequent declines in fertility rates. Such a transition can account for the replacement of infectious diseases by chronic diseases over time due to increased life span as a result of improved health care and disease prevention. This theory was originally posited by Abdel Omran in 1971.
context_section_description: McMichael, Preston, and Murray offer a more nuanced view of the epidemiological transition, highlighting macro trends and emphasizing that there is a change from infectious to non-communicable disease, but arguing that it happens differently in different contexts.
  One of the first to refine the idea of the epidemiological transition was Preston, who in 1976 proposed the first comprehensive statistical model relating mortality and cause-specific mortality. Preston used life tables from 43 national populations, including both developed countries such as United States and England and developing countries such as Chile, Colombia, Costa Rica, Guatemala, México, Panama, Taiwan, Trinidad and Tobago, and Venezuela. He used multiple linear regression to analyze the cause-specific-age-standardized death rates by sex. The estimated slopes represented the proportional contribution of each cause to a unit change in the total mortality rate. With the exception of neoplasms in both sexes and cardiovascular disease in males, all of the estimated slopes were positive and statistically significant. This demonstrated that the mortality rates from each specific cause were expected to decline as total mortality declined. The major causes accounting for the decline were all infectious and parasitic diseases.
  McMichael et al. argue (2004) that the epidemiological transition has not taken place homogeneously in all countries. Countries have varied in the speed with which they go through the transition as well as what stage of the transition they are in. The global burden of disease website provides visual comparisons of the disease burdens of countries and the changes over time. The epidemiological transition correlates with changes in life expectancy. Worldwide, mortality rates have decreased as both technological and medical advancements have led to a tremendous decrease in infectious diseases. With fewer people dying from infectious diseases, there is a rising prevalence of chronic and/or degenerative diseases in the older surviving population.
  McMichael et al. describe life expectancy trends as grouped into three categories, as suggested by Casselli et al.:
  Rapid gains among countries such as Chile, Mexico and Tunisia that have strong economic and technical relationships with developed countries
  Slower plateauing gains mostly among developed countries with slower increases in life expectancy (for example, France)
  Frank reversals occurring mostly in developing countries where the HIV epidemic led to a significant decline in life expectancy, and countries in the former Soviet Union, afflicted by social upheavals, heavy alcohol consumption and institutional inadequacy (for example, Zimbabwe and Botswana)
  Murray and Lopez (1996) offered one of the most important cause-of-death models as part of the 1990 Global Burden of Disease Study. Their "cause of death" patterns sought to describe the fraction of deaths attributed to a set of mutually exclusive and collectively exhaustive causes. They divided diseases into three cause groups and made several important observations:
  Group 1 - communicable, maternal, perinatal, and nutritional: These causes of death decline much faster than overall mortality and comprise a small fraction of deaths in wealthier countries.
  Group 2 - non-communicable diseases: These causes of death are a major challenge for countries that have completed or nearly completed the epidemiological transition.
  Group 3 - injuries: This cause of death is most variable within and across different countries and is less predictive of all-cause mortality.
  The regression approach underlying the Global Burden of Disease received some critique in light of real-world violations of the model's "mutually exclusive and collectively exhaustive" cause attribution.
  Building on the existing body of evidence, Salomon and Murray (2002), further add nuances to the traditional theory of epidemiological transition by disintegrating it based on disease categories and different age-sex groups, positing that the epidemiological transition entails a real trans
caption: Leading causes of DALYs and percentage change between 1990–2013, Zimbabwe
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