[Association between muscle mass and quality of life in Shaanxi adults]

Objective: To investigate the association between muscle mass and quality of life in adults in Shaanxi adults. Methods: The data in this analysis were part of the baseline survey of the Regional Ethnic Cohort Study in Northwest China from June 2018 to May 2019 in Shaanxi Province. The participants' quality of life, including physical component summary (PCS) and mental component summary (MCS), was assessed by the 12-Item Short Form Survey, and the Body Fat Determination System measured muscle mass. A logistic regression model with adjustment for confounding factors was established to analyze the association between muscle mass and quality of life in different genders. Further, sensitivity and subgroup analyses were conducted to explore its stability. Finally, a restricted cubic spline was employed to investigate the dose-response relationship between muscle mass and quality of life in different genders. Results: A total of 20 595 participants were included, with an average age of 55.0, and 33.4% were male. After controlling for potential confounders, compared with the Q₁ group, the risk of low PCS was reduced by 20.6% (OR=0.794, 95%CI: 0.681-0.925) and the risk of low MCS was lower reduced by 20.1% (OR=0.799, 95%CI: 0.689-0.926) in female Q₅ groups. Compared with the Q₁ group, the risk of low PCS was reduced by 24.4% (OR=0.756, 95%CI: 0.644-0.888) in the male Q₂ group. However, no significant association between muscle mass and MCS in males has been found. In females, restricted cubic spline analysis showed a significant linear dose-response relationship between muscle mass and PCS and MCS. Conclusions: There is a positive association between muscle mass and quality of life in Shaanxi adults, especially females. With the increase in muscle mass, the physical and mental functions of the population continue to improve.