Associations between sarcopenia and depression in middle-aged and older adults: the moderating effect of smoking

The aim of this study were to estimate associations of sarcopenic status with depressive symptoms. We used mixed-effects linear model to estimate longitudinal association between sarcopenic status and rate of change in 10-item Center for Epidemiologic Studies Depression (CES-D) scores, and used Cox regression model to estimate the association between sarcopenic status and incident depression (CES-D ≥ 10). Stratification analyses were performed when the interactions between sarcopenic status and covariates were significant. A total of 6522 participants were ultimately included. After adjusting for covariates, participants with possible sarcopenia (β = 0.117; 95% CI 0.067 to 0.166; P < 0.001) and sarcopenia (β: 0.093; 95% CI 0.027-0.159; P < 0.001) had a faster increase in CES-D scores compared with normal individuals. Interactions between smoking and sarcopenic status were significant (P_interaction < 0.05). We found significantly positive associations of sarcopenic status with CES-D scores in nonsmokers, but not in current and past smokers. Besides, compared with normal participants, those with possible sarcopenia (HR 1.15; 95% CI 1.05 to 1.27) and sarcopenia (HR 1.28; 95% CI 1.12 to 1.46) (P_trend < 0.001) had elevated risks of incident depression. Sarcopenia is associated with a faster increase in CES-D scores and increased risks of depression among Chinese middle-aged and older adults. Stronger associations between sarcopenia and trajectory of CES-D scores were found in nonsmokers than in smokers.