Mortalité et inégalités de revenu en France

Are egalitarian societies healthier ? Several recent studies have highlighted an aggregate-level correlation between income inequality and life expectancy. This article uses French individual mortality data to explore competing hypotheses which may explain this correlation. The aim is to determine whether this correlation is a statistical artefact due to the concavity of the health-income relationship (Gravelle, 1996), or if income inequality constitutes one of the determinants of individual health (Wilkinson, 1996). In order to introduce income in the fields of mortality analysis in France, this analysis is based on a case-control study constructed with two fiscal databases, the "Wealth at Death Survey" and the "Taxable Income Survey". The results show a strong association between income and mortality. This association occurs over the whole range of the income distribution, independently of the effect of occupational status. Our results suggest a specific risk related to poverty and lower mortality rates associated with higher incomes, challenging the concavity hypothesis. A multi-level analysis shows, furthermore, that the risk of dying increases with the level of income inequality in the area of residence, after controlling for health care supply and for unemployment rate.