Mechanisms underlying the relationship between the intersectionality of multiple social identities with depression among US adults: A population-based study on the mediating roles of lifestyle behaviors

Background: Despite substantial efforts to investigate the inequalities in mental health among people with marginalized identities, most research has concentrated on single social identities rather than complete persons. The current study aimed to explore the mechanisms underlying the relationship between the intersectionality of multiple social identities with depression among US adults. Methods: Data for this study came from the National Health and Nutrition Examination Survey waves between 2015 and 2018, including a total of 11,268 US adults. A latent class analysis (LCA) was conducted to identify latent subpopulations based on sex, race/ethnicity, immigrant status, disability, household income, employment status, and education level. Interclass differences in lifestyle factors and depression were examined. Multiple mediation analysis was used to examine the mediating roles of lifestyle behaviors. Results: LCA identified four potential subpopulations: "least marginalized", "immigrant minorities", "disabled, less-educated non-workers", and "low-income minorities" groups. There was enormous heterogeneity in mental health among immigrant minority individuals. The "disabled, less-educated non-workers" group had the highest rates of depression; in contrast, the "immigrant minorities" group had the best mental health, even better than that of the "least marginalized" group. Distributions of lifestyle factors followed a similar pattern. In addition, lifestyle behaviors significantly mediated the relationship between intersectional social identities and depression. Limitations: The cross-sectional design prevented establishment of the causality of relationships. Conclusions: This study suggests that applying a person-centered approach is important when examining intersectional inequalities in mental health and highlights the effects of structural social hierarchies on individuals' health behaviors and mental health.