Mechanisms of an eHealth program targeting depression in men with overweight or obesity: A randomised trial

Background: The SHED-IT: Recharge study demonstrated that a gender-tailored eHealth program could improve the depressive symptoms of men with overweight or obesity and low mood. This study examined whether changes in key behaviours and cognitions acted as significant mediators of this treatment effect. Methods: The study was a randomised controlled trial (RCT) including 125 men with overweight or obesity (mean (SD) weight 103.8 (15.8) kg), and current depressive symptoms (Patient Health Questionnaire (PHQ-9) >= 5; mean (SD) 9.2 (4.1) units). Assessments were held at baseline, 3 months (post-intervention), and 6 months (follow-up). Depressive symptoms were assessed using the validated PHQ-9 and Masculine Depressive Risk Scale (MDRS-22). Behavioural and cognitive mediators were assessed with validated measures. Intention-to-treat mediation analyses were conducted using the PROCESS macro in SPSS. Results: Single mediation analyses demonstrated that the intervention effect on both PHQ-9 and MDRS-22 scores was significantly mediated by changes in MVPA, energy-dense nutrient-poor foods, cognitive flexibility, and behavioural activation. In addition, changes in sleep quality mediated improvements in MDRS-22 scores. No mediation effects were observed for light physical activity, sedentary behaviour, fruit and vegetable intake, risky alcohol consumption or mindfulness. Limitations: The study was a secondary analysis with power to detect moderate-to-large mediation effects only. Conclusion: To prevent or treat depression in men with overweight or obesity, early evidence suggests MVPA, sleep quality, energy-dense nutrient-poor food intake, cognitive flexibility, and behavioural activation are important intervention targets.