Many studies have linked depression and obesity; few have more than two assessments of depressive symptoms and adiposity to address the potential bidirectional relationship between adiposity and depressive symptoms from young adulthood through old age. We tested whether baseline depressive symptoms are associated with changes in weight, whether baseline adiposity is associated with changes in depressive symptoms, and whether these associations vary by sex.

Participants (n=2251; 47% female) were from the Baltimore Longitudinal Study of Aging (BLSA). Using hierarchical linear modeling (HLM) on 30 years of data, the trajectory of adiposity and depressive symptoms over adulthood was estimated from >10 000 observations (mean=4.5 assessments per participant) of body mass index (BMI; kg/m2), waist circumference and hip circumference and >10 000 observations (mean=4.5 assessments per participant) of the Center for Epidemiological Studies Depression Scale (CES-D). Baseline depressive symptoms and adiposity were then tested as predictors of the trajectory of adiposity and depressive symptoms respectively. Additional analyses tested for sex-specific associations.

Sex moderated the association between depressive symptoms and weight gain such that women who experienced depressed affect had greater increases in BMI (binteraction=0.12, s.e.=0.04), waist (binteraction=0.22, s.e.=0.10) and hip circumference (binteraction=0.20, s.e.=0.07) across the adult lifespan, controlling for relevant demographic and behavioral covariates. Baseline adiposity was unrelated to the trajectory of depressive symptoms (median b=0.00) for both sexes.

Women who experience symptoms of depression tend to gain more weight across adulthood than men who experience such symptoms. Whether an individual was normal weight or overweight was unrelated to changes in depressive symptoms across adulthood.