Income and inequality as determinants of mortality: an international cross-section analysisa

The determinants of mortality change in less developed countries are not easy to unravel. Improvements in health technology and availability are evidently relevant; education certainly plays an important part; sanitation, clean water supply and a host of other environmental variables have undoubted effects. But empirically, the effects of these different factors are difficult to identify. The variables tend to be collinear with each other, and with many other aspects of development, making their isolation difficult. Moreover, there is a tendency for health programmes to be most intensive in the least healthy places, for obvious reasons, further confusing observed relationships. Identifying the impact of factors such as these, which are directly associated with health, is well worth while for purposes of policy formulation; but it may not be critical for a description of mortality changes in the process of development. For behind these specific variables, the overall economic status of individuals is likely to dominate health changes-through nutrition and other aspects of consumption, and also because economic status is a close correlate and determinant of many of the more specific variables noted above. Higher incomes may be a precondition for healthier environments and better health services, given competing demands on resources-this is self-evident at the community or national level but is also likely to hold at the individual level. Thus, for a general empirical analysis, it is quite reasonable to propose a sequence of causation which goes from income to mortality via a number of intermediate variables with which we need not necessarily concern ourselves.