The research team analysed data on income inequality and mortality by age and sex for 126 countries of the world (94.4 percent of the world human population).
The study confirmed that the impact of income inequality on health is real and that it has a greater influence on mortality in wealthier countries between the ages of 15 and 29, and worldwide between the ages of 25 and 39.
The researchers have said that the strength of this global relationship is reduced when countries in Africa are omitted from the analysis, suggesting that the worldwide result is partly a product of processes operating most strongly in this continent, not simply a reflection of those operating within wealthier countries.
Therefore, the findings of the study show that high levels of inequality have a negative impact on population health in both rich and poor nations alike.
The research team concluded that although the direct mechanisms that operate are likely to be very different between such diverse places, there does not appear to be a beneficial impact of social inequality on health anywhere.