concerns of policy makers in these countries, which arose from those projections and from the focus on aging at the 1982 United Nations World Assembly on Aging. Interest in comparative research involving developing countries has been based on the belief that it can provide insight into the influences of culture and ethnicity, the particular effects of aging in low-income environments, the changing roles of families, and the consequences of new policies and programs.
In this chapter, we review research on the demography of aging in developing countries in several substantive areas, namely, basic demography, mortality and health, family demography, population distribution and migration, and economic activity and well-being. We conclude with a summary of data collection and research challenges and provide an appendix that highlights the current availability of different types of data—survey, census, vital statistic, and ethnographic—for research on these topics.
Much of the early work of demographers on aging in developing countries focused on raising awareness of aging as a policy and research issue. A decade ago, most conference papers and journal articles emphasized projections of population aging and were basically alarmist in their discussions of the implications. No doubt, such consciousness raising was needed. More sophisticated projection work was also done, for example, Yu and Horiuchi's (1987) analysis of the relative contribution of fertility and mortality change, as well as initial age structure, to population aging in more and less developed countries, and Zeng's (1986, 1988) projections of family structure in China.
The essence of the projections is that populations are indeed aging in most of the developing world except parts of Africa; United Nations (1991) estimates for 1990 indicate that 56 percent of the world's 65 and over population already lives in less developed countries. Moreover, some of the populations of East and Southeast Asia are aging at substantially more rapid rates than was the case historically in the West (Chen and Jones, 1989). Figure 10-1 presents the changes over time in median ages for countries that in 1989 had per capita incomes of less than $5,000. The data are taken from the United Nation's (1991) estimates for 1970-1975 and medium-variant projections for 1990-1995 and 2010-2015. The countries are divided into 12 subregions of Latin America, Asia, and Africa. The line in the middle of each box indicates the median of the median ages for the countries in that subregion and period. The height of the box shows the interquartile range (25 to 75 percent) within which the median ages of the middle half of the countries in each subregion fall.
Latin America and Asia show substantial increases in median age over