The mediating role of food insecurity in the relationship between income poverty and depressive symptoms and suicidal ideation: A nationwide study of Korean adults

Background: Income poverty has been linked to poor mental health. Food insecurity, a consequence of poverty, has been identified as a determinant of mental health. We explored the mediating role of food insecurity in the relationship between income poverty and mental health problems. Methods: This study utilized a nationally representative sample of 12,918 adults from the 2019-2021 Korea National Health and Nutrition Examination Survey, among whom 3,896 were included in the depressive symptom analysis and 9,022 in the suicidal ideation analysis. Income poverty was defined as having a household income below 50 % of the median. Food insecurity was assessed using the Korean version of the 18-item Household Food Security Survey Module and was dichotomized as the presence of food insecurity if three or more items received affirmative responses. Logistic regression and mediation analyses were conducted, with odds ratios (ORs) and 95 % confidence intervals (CIs) computed. Models were adjusted for gender, region, education, employment status, marital status, presence of a child, smoking, physical exercise, and alcohol use. Results: Among the sample, the prevalence was 15.1 % for income poverty, 3.8 % for food insecurity, 3.9 % for depressive symptoms, and 3.2 % for suicidal ideation. Poverty was associated with a 1.5 % (95 % CI: 1.3 %-1.6 %) increase in the likelihood of depressive symptoms compared to non-poverty conditions, with food insecurity accounting for 52.7 % (95 % CI: 46.8-58.2 %) of this effect (average causal mediating effect [ACME]: 0.008, 95 % CI: 0.006-0.009). Additionally, income poverty was associated with a 2.0 % (95 % CI: 1.9 %-2.1 %) increase in the likelihood of suicidal ideation compared to non-poverty conditions, with food insecurity accounting for 17.7 % (95 % CI: 15.7-19.8 %) of this effect (ACME: 0.004, 95 % CI: 0.003-0.004). Conclusion: Food insecurity can mediate a meaningful portion of the relationship between poverty and mental health problems, highlighting the importance of targeted public health to address food access.