In looking at patterns and variables in causes of death worldwide, it is important to consider physical, economic, social, and environmental factors, as well as the age structure of different populations. In the early 1990s, for example, the developed countries of the world accounted for 11 million of the world's nearly 50 million deaths. The large majority of these (10.4 million) were due to noncommunicable diseases—mainly cardiovascular disease (5.3 million), cancer (2.3 million), respiratory disease (0.5 million), and injuries (about0.7 million). Of all deaths occurring in developing countries, however, 40 percent (16 million) were due to communicable, maternal, and perinatal causes, and 60 percent to noncommunicable diseases (18 million) and injuries (3.5 million). Deaths from injuries caused roughly the same proportion of deaths in both developed and developing regions, but were twice as common among males than among females.

In developing countries, differences occur in the distribution of causes of deaths. The probability of dying before the age of fifteen varies according to sex and cause of death in the various areas, though the breakdown between communicable and noncommunicable disease is similar to that discussed above (see Figure 1). Discrepancies are largely due to the methods used to estimate the number of deaths.

The distribution of causes of mortality is changing, and is likely to continue to change. In developed countries, deaths from communicable diseases and perinatal and maternal causes fell from 6 percent to 2 percent of all deaths between 1985 and 1997, while the percentage in the developing world fell only slightly, to 53 percent. Over the same period, deaths from cardiovascular diseases fell from 51 percent to 46 percent of all deaths in developed countries, but increased from 16 percent to 24 percent in the least developed countries—those countries where manufacturing accounts for

Figure 1

less than 10 percent of GDP, where adult literacy is less than 20 percent, and where the per capita GDP is $100 (1968) or less.

A comparison of the extremes of the spectrum of development shows a marked difference in the age distribution of deaths. In developed market economies less than 2 percent of deaths occur before the age of twenty (this is likely to be 1 percent by 2025), while in the least developed countries the figure rises to 40 percent (23 percent by 2025). Similarly, deaths above the age of sixty-five represents about 77 percent of all deaths in the developed market economies (projected to 88 percent by 2025), but only about 12 percent (31 percent in 2025) in the developed countries.

The impact of health structures within a nation is less well known, but is likely to affect mortality. One striking case is that of AIDS (acquired immunodeficiency syndrome). New therapies have led to a marked fall in deaths from AIDS in the developed world. With few exceptions (e.g., Brasil), however, these therapies are not systematically applied in developing countries, for reasons of cost, and a lack of adequate health structures for distribution and education, and deaths from AIDS in those countries continue to rise. Both the age structure of a population and the conditions under which it lives will thus affect not only the amount of death a population encounters, but the way the death comes.

MICHEL C. THURIAUX

(SEE ALSO: Certification of Causes of Deaths; Infant Mortality Rate; Mortality Rates)