Sex differences in the association between the muscle quality index and the incidence of depression: A cross-sectional study

Abstract

BACKGROUND Depression presents significant challenges to mental health care. Although physical activity is highly beneficial to mental and physical health, relatively few studies have conducted on the relationship between them. AIM To investigate the association between muscle quality index (MQI) and incidence of depression. METHODS The data used in this cross-sectional study were obtained from the 2011-2014 National Health and Nutritional Examination Survey, which included information on MQI, depression, and confounding factors. Multivariable logistic regression models were employed, while taking into account the complex multi-stage sampling design. A restricted cubic spline model was utilized to investigate the non-linear relationship between the MQI and depression. Additionally, subgroup analyses were performed to identify influential factors. RESULTS The prevalence of depression in this population was 8.44%. With the adjusted model, the MQI was associated with depression in females (odds ratio = 0.68, 95% confidence interval: 0.49-0.95) but not in males (odds ratio = 1.08, 95% confidence interval: 0.77-1.52). Restricted cubic spline adjustment of all covariates showed a significant negative non-linear relationship between depression and the MQI in females. The observed trend indicated an 80% decrease in the risk of depression for each unit increase in MQI, until a value of 2.2. Subsequently, when the MQI exceeded 2.2, the prevalence of depression increased by 20% for every unit increase in the MQI. Subgroup analyses further confirmed that the MQI was negatively associated with depression. CONCLUSION The MQI was inversely correlated with depression in females but not males, suggesting that females with a higher MQI might decrease the risk of depression.