National income inequality and self-rated health: the differing impact of individual social trust across 89 countries

The well-known Income Inequality Hypothesis suggests that income disparities in a country are detrimental for people's health. Empirical studies testing this hypothesis so far have found mixed results. In this study, we argue that a reason for these mixed findings may be that high national income inequality mostly harms individuals with high levels of social trust. We employ data of the World Value Survey and European Value Survey, using information on 393,761 respondents within 89 countries. Multilevel regression analyses, across countries and within countries across time, confirm findings from earlier studies that there is a negative association between national income inequality and self-rated health. Our results also reveal that national income inequality is especially detrimental for trustful citizens: while the effect of income inequality is nearly absent among people with low social trust it is negative among people with high social trust.