Relation between income inequality and mortality in Canada and in the United States: cross sectional assessment using census data and vital statistics

Objective To compare the relation between mortality and income inequality i n Canada with that in the United States. Design The degree of income inequality, defined as the percentage of total household income received by the less well of 50% of households, was calcul ated and these measures were examined in relation to all cause mortality,gr ouped by and adjusted for age. Setting The 10 Canadian provinces, the 50 US states, and 53 Canadian and 28 2 US metropolitan areas. Results Canadian provinces and metropolitan areas generally and both lower income inequality and lower mortality than US states and metropolitan areas . In age grouped regression models that combined Canadian and US metropolit an areas, income inequality was a significant explanatory variable for all age groupings except for elderly people. the effect was largest for working age populations, in which a hypothetical 1% increase in the share of incom e to the poorer half of households would reduce mortality by 21 deaths per 100 000, Within Canada, however, income inequality was not significantly as sociated with mortality. Conclusions Canada seems to counter the increasingly noted association at t he societal level between income inequality and mortality. The lack of a si gnificant association between income inequality and mortality in Canada may indicate that the effects of income inequality on health are not automatic and may be blunted by the different ways in which social and economic reso urces are distributed in Canada and in the United States.