Income disparities in mental health: investigating the role of food insecurity by disability status

OBJECTIVE: To investigate whether food insecurity helps explain the association between income and psychological distress and if its role differs by disability status. DESIGN: Using 2011–2017 National Health Interview Survey cross-sectional data (n 102 543), we conducted linear regression models, fully interacted with disability status, to estimate the association between income-to-poverty ratio (IPR) (<1, 1–<2, 2–<4, ≥4) and psychological distress (Kessler 6 (K6) Scale, range: 0–24). Base models adjusted for socio-demographic factors. We then added food security (secure, low and very low), interacted with disability, and conducted post-estimation adjusted Wald tests. SETTING: USA. PARTICIPANTS: Nationally representative sample of non-institutionalised adults 18 years and older. RESULTS: The association between income and psychological distress was stronger for people with disabilities. Compared to those in the highest income category (IPR ≥4), poor individuals (IPR < 1) with and without disabilities scored 2·10 (95 % CI (1·74, 2·46)) and 0·81 (95 % CI (0·69, 0·93)) points higher on the K6 Scale, respectively. Accounting for food insecurity reduced the estimated income disparity in psychological distress significantly more among individuals with disabilities (0·96 points or 46 %) than without disabilities (0·34 points or 42 %), decreasing the difference in the income disparity between those with and without disabilities by 48 % (0·62 points). Further, food insecurity more strongly predicted psychological distress for individuals with disabilities independent of socio-economic disadvantage. CONCLUSIONS: Food insecurity plays a more important role in shaping patterns of psychological distress for people with disabilities, explaining more of the association between income and psychological distress among those with than without disabilities. Improving food security may reduce mental health disparities.