Depressive symptoms mediate the relationship between sustained food insecurity and cognition: a causal mediation analysis.

Purpose: This study aimed to investigate the association of change in food insecurity over time with cognitive function in midlife, and whether depressive symptoms mediated that relationship.

Methods: We used longitudinal data from the Coronary Artery Risk Development in Young Adults study. Change in food insecurity in 2000-2005 was coded as "persistently food-secure," "persistently food-insecure," "became food-insecure," and "became food-secure." Depressive symptoms were measured in 2010, and cognitive function was measured in 2015. Multivariable linear regression controlled for sociodemographic and cardiovascular health factors was used. We also conducted causal mediation analysis.

Results: Our study population included 2448 participants (57.23% female and 43.18% Black, mean age = 40.31 in 2000). Compared with persistent food security, persistently and became food-insecure were associated with worse cognition, particularly with processing speed (β = -0.20 standard unit, 95% CI = -0.36, -0.04; β = -0.17, 95% CI = -0.31, -0.03), and these associations appeared mediated by depressive symptoms (proportion-mediated = 14% for persistently food-insecure and 18% for became food-insecure).

Conclusions: Persistent and transition to food insecurity were associated with worse cognition, both directly and indirectly through increasing depressive symptoms. Targeting food insecurity or depressive symptoms among persistently or became food-insecure individuals may have the potential to slow premature cognitive aging.