Large variation in the epidemiological transition across countries: is it still valuable as a mortality theory?

摘要

Omran’s epidemiological transition is one of the main theories of global mortality change. In his initial paper, Omran1 outlined a broad model that sought to link epidemiological and social factors with the demographic transition theory—the major population theory which described population growth as arising from the lag between declines in death and birth rates, while population age structures transitioned from young to older.2,3 Omran sought to draw a deeper focus on the mortality determinants of demographic transition, which had received comparably less attention than the determinants of fertility decline. In this way, Omran classified human populations into distinct stages, each characterized demographically (levels and volatility of death rates, fertility rates, and population growth rates) and epidemiologically (cause-of-death contributions). His initial paper had three ‘Ages’ (the age of pestilence and famine, the age of receding pandemics and the age of degenerative and man-made diseases), and Omran himself later expanded this to include the age of declining cardiovascular mortality, ageing, lifestyles modification and emerging and resurgent diseases, and a fifth yet-unrealized age of aspired quality of life.5 The core theoretical value of the epidemiological transition is that, given some information on the level of mortality in a population (such as life expectancy at birth), we should be able to meaningfully infer a host of current and future population characteristics including growth and fertility rates and cause-of-death profiles.