The changing relation between mortality and level of economic development

Abstract

The influence of economic conditions on mortality has been recognized at least since biblical times. Empiricism of the most casual sort was sufficient to establish the link between food supply and mortality. Other components of living standards, such as shelter and living space, awaited a revolution in scientific method before their influence was finally acknowledged. But recent years have witnessed a movement away from economic determinism in mortality analysis. It is widely believed that mortality has become increasingly dissociated from economic level because of a diffusion of medical and health technologies, facilities and personnel that occurred, in large part, independently of economic level, yet this position has its critics who have gained a sympathetic audience.1–4 This article utilizes readily available evidence in a new but obvious way to estimate the relative contribution of economic factors to increases in life expectancy during the 20th century. The evidence consists of cross-sectional relationships between national life expectancies and national income per head evaluated during three different decades of the 20th century. These relationships are further used to assess the realism of certain economic-demographic models and to re-examine what have become classical distinctions regarding sources of mortality declines in Western and non-Western areas. There are several reasons for focusing on national income rather than on another socio-economic variable. First, national income is probably the best single indicator of living standards in a country, since it comprises the value of all final products (goods and services) produced in a certain period. A wide range of these products can be expected to influence mortality, and expenditures on all of them are represented, with varying weights, in national income. It is the indicator most comprehensive of these multiple factors. Secondly, as the leading index of level of economic development, income per head is the focus of growth models from which policy measures are derived. … National income per head in constant dollars is an index of the total value of final products produced per inhabitant during a defined period, exclusive of goods which merely replace losses from depreciation of capital equipment. There is no reason to expect a direct influence of national income per head on mortality; it measures simply the rate of entry of new goods and services into the household and business sectors. Its influence is indirect; a higher income implies and facilitates, though it does not necessarily entail, larger real consumption of items affecting health, such as food, housing, medical and public health services, education, leisure, health-related research and, on the negative side, automobiles, cigarettes, animal fats and physical inertia. Levels of mortality and economic development can be related to one another conceptually and substantively in a variety of ways. It is useful at the outset to distinguish among at least three different types of relationships that have been proposed by various analysts, although the exact formulation is often only implicit in their work. In order to simplify the task, we confine the review to international studies. Attempts at empirical estimation have focused on the cross-sectional relationship between mortality and economic level. Most commonly, the relationship between national infant mortality rates and levels of income has been examined.5–7 Coefficients of correlation between the variables have been found to be consistently high, of the order of −0.8. The relationship is sufficiently strong for infant mortality rates on occasion to have been used as indicators of income levels when the requisite data for computing the latter are missing.8 Gordon et al.9 have suggested that the death rate of children in their second year of life may be a better indicator of general health levels than infant morality, which responds to a number of influences not present at other ages. Frederiksen2 provides partial support by showing that death rates at ages 1–4 are more closely correlated with gross national product per head in 15 countries than are death rates at ages 0–1, 20–24, or 65–69. One study, confined to less developed countries, has demonstrated a close cross-national relationship between an index of mortality at all ages and from all causes, life expectancy at birth and the level of national income. Vallin suggests that no country can attain a life expectancy of more than 60 years without having made very substantial progress out of the category, ‘less developed’.10 At the same time, he stresses that the relationship is not deterministic and that a nation can, within limits, modify its life expectancy independently of its level of income. We shall re-examine the type of relationship studied by Vallin in a subsequent section. On several occasions the United Nations Population Division has expressed the opinion that the cross-sec