Poor Mental Health Is Related to Excess Weight via Lifestyle: A Cross-Sectional Gender- and Age-Dependent Mediation Analysis.

Within mental health as risk factor for excess weight, prevention-relevant questions remain: does the relation persist after considering lifestyle, which lifestyle parameters might be most important to target, which gender or age subgroups are most at risk? The cross-sectional Belgian health survey 2013 (n = 4687; ≥15 years) measured mental health via anxiety and depression symptoms (Symptom Check List 90-R) and distress (General Health Questionnaire-12). Logistic regression, multiple mediation and moderated mediation were applied. Poor mental health was significantly related to a higher excess weight prevalence (odds ratio (OR) = 1.18 with 95% confidence interval (0.17-1.19)) and an unhealthier lifestyle i.e., more smoking, sleep problems, disordered eating, soft-drink, and alcohol consumption; while less fruit/vegetables and physical activity and even lower snack intake. Associations were often gender- and age-specific e.g., poor mental health was only related to less snacking in men and middle-adulthood, while an association with more snacking appeared in youth (<25 years). Disordered eating, physical activity and smoking were significant mediators explaining 88% of mental-weight associations, after which the association became negative (OR = 0.92 (0.91-0.93)). Mediation by snacking and disordered eating was stronger in the youngest and mediation by smoking was stronger in women. Thus, especially youth has high mental health associated behavioral and weight risks and gender or age differences can explain conflicting literature results on lifestyle.