Dietary influence on the link between depression and muscle mass and muscle strength: exploring interaction and...

The present study aimed to investigate the associations of depression with muscle mass and muscle strength, and whether these associations were modified or mediated by dietary energy intake and dietary quality.

Our study included participants aged 40 and above from the 2011-2018 cycles of the National Health and Nutrition Examination Survey (NHANES). Depression was evaluated using the nine-item Patient Health Questionnaire. Skeletal muscle mass index (SMI) and handgrip strength (HGS) were used to evaluate muscle mass and muscle strength, respectively. Information on dietary intake were obtained via dietary recall. Dietary quality was assessed using healthy eating index-2015 (HEI-2015). We performed multivariable linear regression models to examine the associations of depression with SMI (N = 3,648) and HGS (N = 4,679). Interaction analyses and mediation analyses were conducted to test the effect of dietary energy intake and HEI-2015 on the associations of depression with SMI and HGS.

Depression was associated with decreased SMI and HGS. Interactions between depression and HEI-2015 were observed for SMI, but not for HGS. The stratified analyses showed that depression was associated with decreased SMI in participants whose HEI-2015 were lower than the median. Mediation analyses revealed that dietary energy intake mediated the associations of depression with SMI and HGS.

HEI-2015 modified the associations between depression and muscle mass. The inverse associations of depression with muscle mass and muscle strength were partially mediated by dietary energy intake. These findings emphasized the importance of dietary energy intake and dietary quality in preventing muscle loss in middle-aged and older participants with depression.