UCLA

Background: Obesity and depressive symptoms are major public health problems, as, epidemiological studies suggest that depressive symptoms are linked to obesity. However, potential behavioral pathways linking depressive symptoms to obesity have not well examined.

Purpose: The main purpose of this study was to assess behavioral factors as potential mediators between depressive symptoms and body mass index (BMI) and waist circumference (WC). Other objectives included: 1) examining the direct effects of depressive symptoms on BMI and WC and other cardiovascular disease (CVD) risk factors: 2) and examining the moderating effects of perceived social support on the association of depressive symptoms and BMI.

Methods: Data on U.S. adults with a mean age of 40 from the CARDIA study was used in multivariate regression analyses models to test the association between depressive symptoms and BMI and other CVD risk factors. Path analysis using EQS was used to test the behaviors as mediators in the association of depressive symptoms and BMI and WC. Measures included the Center for Epidemiologic Studies-Depression (CES-D) scores, frequency of fast food consumption per week, physical activity score, sleep quality and objective measures of BMI and WC.

Results: Depressive symptom scores were positively associated with BMI, WC, triglycerides and fasting blood glucose and negatively associated with HDL levels in the whole cohort. Perceived social support did not moderate the association between depressive symptoms and BMI. However, after subgroup analyses, the association between depressive symptoms and WC remained stronger in females as compared to males. Mediation analyses showed that physical activity was the only significant mediator that linked depressive symptoms to BMI and WC in the entire cohort.

Conclusion: Physical activity might be a potential pathway factor linking depressive symptoms to BMI and WC. Obesity prevention strategies should take these results into consideration and create innovative interventions to increase physical activity in individuals with higher levels of depressive symptoms with specific attention directed to females. Future studies are still needed to comprehensively examine the combination of mechanisms that link depressive symptoms to BMI and WC.