Psychological Distress Mediates the Prospective Association of Household Income with Body Mass Index in Adolescent Girls.

The primary objective of this study was to examine whether psychological distress mediates the relationship between income and increases in body mass index in adolescent girls. To answer this question, we analyzed data from 2379 participants in the longitudinal NHLBI Growth and Health Study using regularized regression and path analysis. The exposure was household income at age 9-10 and the outcome was body mass index at age 18-19. Income negatively predicted psychological distress, which in turn predicted psychological and behavioral factors that were associated with increases in body mass index. Overall, psychological distress and related variables accounted for around 20% of the relationship between income and increases in body mass index in adolescent girls. The impacts of income on a complex constellation of psychological risks for obesity support the evaluation of income support policies for reducing economic inequalities in obesity. Obesity reduction programs focused on changing psychological distress should be developed with consideration of the household economic environment.