Disease (morbidity) and death (mortality) have always been part of the human experience. Epidemiology studies the causes and distribution of health, morbidity, and mortality in various populations. One approach that is useful for [Page 244]considering, through history, the interaction of environmental factors and human behaviors with regard to health outcomes is the theory of epidemiological transition.

The epidemiological transition describes changing patterns of population distributions in relation to changing patterns of mortality, fertility, life expectancy, and leading causes of death. The perspective has its origins in demography but finds a compatible conceptual home in public health and epidemiology in particular. The very term epidemiological transition raises the question of transition—from what to what? There are 2 major components of the transition: (a) changes in population growth ...