Dynamics and Patterns of Mortality Change
Citation: Murray, Chen (1994) Dynamics and Patterns of Mortality Change.
This introductory chapter of Health and Social Change in International Perspective deals with the question "What is a health transition?" Caldwell (1989) suggests that the term "health transition" be used to describe the social and behavioral changes that coincide with the epidemiological transition and may in fact precede it. Murray and Chen stress that the study of health transitions requires careful definition of the term "health." The traditional approach has been to define health in terms of mortality (i.e., life expectancy). The problem with this approach is that it does not account for morbidity or functional mobility, both of which have a profound effect on the healthiness or "quality" of life years. However, Murray and Chen stop short of arguing that concepts like "well-being" should be included since they make "health indistinguishable from general welfare" (p. 4). Having defined health as life expectancy weighted by morbidity and disability, Murray and Chen proceed to compare theories of health transition with the empirical evidence from several nations around the world-particularly in developing nations. According to demographic transition theory (DTT), mortality declines in a "monotonic, linear fashion" (p. 6). The simple assumptions embedded in DTT, such as steady rates of mortality decline and constant social patterns of mortality change (e.g., age patterns), are not supported by the evidence. Rather, both the pace and structure of mortality decline can vary substantially both between and within nations. For instance, international efforts to reduce child mortality in developing nations have resulted in nonuniform age patterns of mortality decline. Also, the sex structure of mortality has shown a wide variety of patterns throughout the health transition-although excess female-to-male mortality generally becomes less common as societies move through health transitions. Finally, social groups that are disadvantaged due to racial identification or social class almost always experience higher rates of mortality than their more advantaged counterparts. In fact, several studies have shown a clear gradient effect of social hierarchy on life expectancy. Although most nations do not experience interruptions in mortality decline once the health transition begins, there are exceptions. For instance, death rates for males in Eastern Europe increased from 1952 to 1985 due to rising cardiovascular mortality. Also, the AIDS virus in sub-Saharan Africa has dramatically reversed gains in life expectancy. As developing nations move through the health transition, they typically experience a decline in infectious diseases and a rise in chronic diseases. The latter increase because (1) the age structure becomes older as nations move through the DTT and (2) risk factors become more prevalent. However, contrary to the common assumption that the cause of death structure (e.g., predominantly chronic disease mortality) is dependent on the overall level of mortality (e.g., low mortality in post transition societies), Murray and Chen argue that "many causes of death exhibit no statistically significant relationship with overall mortality" (p. 15). A good example of this is Japan, which exhibits no increase in cardiovascular disease rates, despite low and declining rates of adult mortality. Therefore, "whether [CVD] rates rise of fall appears to depend on the balance of change in risk factors. The lack of a correlation between changes in [CVD] mortality and total mortality across countries suggests that change in risk factors may occur independently of mortality decline, making generalizations about rises in chronic disease mortality rates untenable" (p. 17).