Physical exercise and body mass index as correlates of major depressive disorder in community-dwelling adults: Results from the PISMA-ep study

Background: Major Depressive Disorder (MDD) is one of the most prevalent and disabling mental disorders. Sedentarism and obesity are recognized risk factors for MDD. Physical exercise has shown beneficial effects on mental health and there is an increasing awareness of its potential as a therapeutic and preventive tool for depression. No epidemiological studies have explored the role of physical activity and obesity as potential correlates of MDD in the Spanish population. The aim of this study was to explore whether MDD was associated with two strongly linked variables: physical exercise and body mass index. Methods: The PISMA-ep is a cross-sectional community-based study carried out in Andalusia, southern Spain. Main outcome was current prevalence of MDD, measured through face-to-face interviews using the Mini-International Neuropsychiatric Interview (MINI). Independent variables explored were physical exercise and its intensity, Body Mass Index (BMI), BMI categories (underweight, normal weight, overweight and obesity), hip and waist circumferences, general health status measured with the SF12 questionnaire, and sociodemographic factors. Results: Physical exercise was inversely associated with MDD, acting as a protective factor. Higher intensity of exercise strengthened this association. Four variables were independently associated with MDD in the multivariate association model: female sex, physical exercise, general health status and BMI. Conclusion: MDD was associated with poorer health status, higher BMI and reduced physical activity. Physical exercise should be considered as a potential intervention for the treatment and prevention of MDD in clinical and public health settings.