Our paper provides evidence on how different measures of stratification can explain differences in health in a large sample of 18 EU countries. We replicate the positive association of income and health [
28] and the negative association of income inequality and health [
29‐
32]. By applying the innovative logit rank tool to income, analyses confirmed a linearly increasing health gradient even at the very extremes of the distribution, suggesting that it is always better in terms of health to have a higher socioeconomic position, even for individuals at the very bottom or very top of the distribution. Similar to Wilkinson and Pickett (2010) who basically argue that inequality is systemic stress for the population and leads to decreases in population health, our findings suggest that in Europe higher income is good for health, but inequality as such threatens country’s average health level. The finding that income inequality is negatively related to average health suggests that nations with higher inequality levels could be neglecting public health issues which leads to lower health for the general population.
In line with our findings, social origins have been shown to have important influences on adult health [
28,
33], and our study extends these findings insofar as even after detailed controls for current socioeconomic position, social origins are still associated with self-rated health. Further, income inequality increased the association of social origins with health across countries. These findings show that even in meritocratic countries, there is intergenerational transmission of health via parental socioeconomic status after controlling current measures of individual socioeconomic position (which may also be influenced by parental socioeconomic status). A more unexpected pattern was that with higher income inequality, income-health gradients were attenuated. This paradoxical finding can be explained by comparatively high Northern European income-health gradients and, conversely, low income-health gradients of Italy, Spain and Poland. Indeed, our findings echo the European income-health estimates of Beckfield and Olafsdottir who investigated low-income disadvantages and high-income advantages in health in the World Values Survey: While Beckfield and Olafsdottir report for Norway both high low-income disadvantage AND high-income advantage for health, our analyses produce comparatively large health gradients for Norway, meaning that within the low range of income distribution, health levels vary greatly [
34]. The negative association of income inequality with the income-health association could also be due to sampling specificities in this sample of 18 high-income countries – as was shown, only few countries show associations in the expected direction of positive associations of income inequality and health gradient such as United Kingdom and Iceland. This ‘public health puzzle’ or ‘paradox’ of high inequalities in egalitarian Northern European regimes has been noted several times in the literature and common explanations of life course, health selection and other causes can only partly explain this finding [
35,
36]. However, it is more likely that unobserved country characteristics have produced this finding: Other country characteristics with evidence of producing differences in the health gradient are welfare regimes [
37‐
41], political systems [
42], health expenditures and labour market conditions [
43], public versus private-based healthcare systems [
44], social expenditures [
45], and health policy performance [
46]. The pattern of our findings does not obviously point to one of those explanations. It may be possible though that in this sample of respondents from Northern European countries, low levels of income inequality mask large health gaps between lower and higher socioeconomic groups, and may be a result of class-specific attitudes and (health) behaviors [
3,
47]. Concerning the sample of Southern European countries Portugal, Poland, Italy, and Spain, all with a high rate of members of the Catholic church compared to the other countries in this study, it could be argued – as all countries with this positioning of health gradient and income inequality are known for their familialistic welfare system – that high income inequality is buffered by traditional family systems and may increase especially health of lower socioeconomic groups. This familialistic protection, perhaps motivated by religious practices, may be one of the reasons why the health gradient in those countries was not as steep as expected. However readers should note that this study was not designed to assess the influence of country-level familialism on the health gradient, and further studies should move forward to possible explanations for the low association between income inequality and health gradient. Another possible explanation would be reporting differences in health, which has been shown e.g. with health vignettes from SHARE [
48], but which do not reflect the pattern of educational inequalities we find in the EU-SILC data.
Additional analyses with limiting long-standing illness (LLSI) as outcome confirmed overall robustness of our results, although the general picture with this indicator was less clear compared with the analyses on self-rated health. This is not surprising considering that cross-national patterns with LLSI have been called enigmatic [
49]. Further, the association between self-rated health and disability gradient has been shown to be subject to welfare state differences itself [
41]. Further studies should explore in more detail the associations of income inequality, income-health gradient and limiting long-standing illness, preferably with a more age-heterogeneous sample.