Does self-perceived income priority matter? The association between income inequality and allostatic load in China

There is a scarcity of evidence about the association between income inequality and allostatic load (AL) across diverse population, which is critical to identify the downstream biological pathway of the inequality-health linkage. This study aimed to determine the association of income inequality with AL, and assess whether there are differences in such association between people with different perception of income priority. We utilized data from the 2006 and 2009 wave of China Health and Nutrition Survey (CHNS). Multilevel linear regression analyses were conducted to examine the association between AL score and community Gini coefficient. Additionally, to investigate whether the association of income inequality and AL score would vary among individuals with different perception of income priority, a cross-level interaction term for Gini coefficient and self-perceived income priority was applied. Both the cross-sectional analysis in 2009 (coefficient = 0.081, p = .016) and the time-lagged analysis (0.106, 0.008) suggested that community-level Gini coefficient was positively associated with AL. Similar result was only found among individuals from low median income communities in subsample analysis. Additionally, the cross-level interaction between Gini coefficient and self-perceived income priority was significantly associated with AL among respondents from low-median income communities. There is a positive association between income inequality and AL among Chinese adults, with individual who perceived income as a higher priority in their life suffering more from income inequality. This study contributes to the increasing efforts and new perspective to understand the inner mechanism of both the detrimental effect of income inequality and the accumulation of AL.