The conditional effect of income distribution on mortality risk of men in Tunisia: Poverty effect or wealth effect?

Abstract

The paper examines the conditional effect of income on mortality risk of men in Tunisia in a population based case-control survey study combining individual data from two databases on 11,231 survivors and 1,498 deceased. The main question addressed in the study is whether inequalities in health, as measured by mortality, in Tunisia mainly reflect the effects of poverty or are they caused by a socioeconomic gradient? Using logistic regression models with various income specification, our empirical findings provide strong evidence of an excess mortality associated with poverty, but also, unexpectedly, an under mortality associated with highest incomes. Beyond an absolute poverty effect, we fail to find support for the hypothesis of a concave relationship between income and mortality since we highlight a protective effect of the highest incomes. Besides, under the different income specifications estimation results confirmed the significant effect of income on mortality risk, regardless of the socio-professional categories effects. This effect is not limited to poverty, since the mortality risk decreases continuously throughout the income distribution calling into question the effects of socioeconomic gradient on mortality risk.