Lynch, John W., G. Davey Smith, Marianne M. Hillemeier, M. Shaw, Trivellore Raghunathan, and George A. Kaplan. 2001. "Income Inequality, the Psychosocial Environment and Health: Comparisons of Wealthy Nations." Lancet, 358: 194-200.
Cognizant of the dangers of overinterpretation, what can we reasonably conclude from these patterns of findings? It seems there is a fairly strong and consistent pattern of associations between income inequality and child health outcomes. Higher income inequality was associated with higher infant mortality, low birthweight, and mortality in people aged 1-14 years in both sexes. For a country of such vast wealth, the USA has very high income inequality and poor child health. Associations with infant and early-- life mortality largely disappeared when the USA was excluded from analyses (data not shown), but an association with low birthweight remained due to high levels of both income inequality and low birthweight in the UK. Associations with mortality above age 65 were the opposite of that predicted by the theory that higher income inequality is automatically bad for health. These negative associations were largely driven by the fact that higher inequality countries like the USA and France have relatively low mortality above age 65, especially for CHD, compared with countries like Finland, Denmark, Luxembourg, and Germany. The age-specific pattern of associations between income inequality and mortality may be consistent with time lags. It is widely recognised that income inequality within many of these countries generally narrowed after the second world war, but increased markedly after the 1970s, and so it is possible that the current associations reported with child health outcomes could be reflected in differences in adult health in the future, as populations exposed to this period of increasing inequality age. Long-term data on changes in inequality and health are needed to explore this hypothesis.