[The correlation of physical activity and sedentary leisure time with low muscle mass, strength, and quality in Chinese adults].

Objective: To explore the relationship of physical activity and sedentary leisure time with muscle mass, strength, and quality in Chinese adults. Methods: Based on the second resurvey of China Kadoorie Biobank (CKB) in 2013-2014, logistic regression models were used to analyze the correlation of physical activity and sedentary leisure time with low muscle mass, grip strength, and muscle quality. Results: A total of 24 245 participants were included in the analysis. The average daily physical activity level was (18.3±13.8) MET-h/d, and the sedentary leisure time was (4.4±1.9) hours. We took the lowest physical activity quartile as the reference and found that the participants' physical activity was negatively correlated to low muscle mass, strength, and quality. The ORs (95%CIs) of low appendicular skeletal muscle mass index (ASMI), low total skeletal muscle mass index (TSMI), low grip strength and low arm muscle quality (AMQ) were 0.68 (0.60-0.77), 0.66 (0.58-0.75), 0.82 (0.72-0.94) and 0.84 (0.74-0.95), respectively. The subtypes of physical activity, including those related to work, transportation, housework, and leisure, also showed negative correlations with low muscle mass, strength, and quality to varying degrees. Compared with participants with the shortest sedentary leisure time, those who had the longest were more likely to have low TSMI (OR=1.13, 95%CI: 0.99-1.30). Conclusions: Physical activity was negatively correlated with a lower risk of low muscle mass and strength, while longer sedentary leisure time positively correlated with low muscle mass.目的： 探索我国成年人体力活动、休闲静坐时间与低肌肉重量、力量和质量的关系。 方法： 利用中国慢性病前瞻性研究（CKB）项目的第二次重复调查，采用logistic回归分析体力活动水平、休闲静坐时间与低四肢肌肉重量指数（ASMI）、低全身肌肉重量指数（TSMI）、低肌肉力量和低肌肉质量（AMQ）的相关性。 结果： 研究纳入24 245名研究对象，体力活动水平为（18.3±13.8）MET-h/d，休闲静坐时间为（4.4±1.9）h。以体力活动最低组为参照组，高水平的体力活动与较低的低ASMI、低TSMI、低手握力和低AMQ有关，对应的OR值（95%CI）分别为0.68（0.60~0.77）、0.66（0.58~0.75）、0.82（0.72~0.94）和0.84（0.74~0.95）。工作、交通、家务和休闲相关体力活动亚型亦与上述指标呈现不同程度的负相关。与休闲静坐时间最短组相比，静坐时间最长组低TSMI的危险性增加（OR=1.13，95%CI：0.99~1.30）。 结论： 体力活动与低肌肉重量、力量和质量呈负相关，而休闲静坐时间与低肌肉重量呈正相关。.