Income distribution and cause-specific mortality

The aim was to identify the age-, sex- and cause-specific premature mortality rates contributing to the association between life expectancy and income distribution in developed countries. Income distribution was calculated for the 13 OECD countries and years for which the Luxembourg Income Study held data. The potential years of life lost (1–65 years) by sex and cause, as well as the age- and sex-specific all-cause mortality rates and standardized mortality ratios for children 1–19 years were calculated from data supplied by the WHO. On finding evidence suggesting that reported income distribution is strongly affected by low response rates in some income surveys, we used 2 measures of income distribution: that among households where the 'head of household' was aged less than 65 years (weighted by response rates) and that among households with children (among whom response rates are thought to be higher). Partial correlations and regressions controlling for the year were used to analyse the relationship between mortality and income distribution. Both measures of income distribution showed broadly similar results. A more egalitarian distribution of income was related to lower all-cause mortality rates In both sexes in most age groups. All 6 major categories of cause of death contributed to this relationship. The causes of premature mortality contributing most were road accidents, chronic liver disease and cirrhosis, infections, Ischaemic heart disease among women and other Injuries among men. Income distribution was associated not only with larger absolute changes in mortality from these causes, but also with larger proportionate changes. Suicides and stomach cancer tended to be more common In more egalitarian countries.