Association of muscle quality index with circadian syndrome: Evidence from NHANES

Muscle Quality Index (MQI), a novel health metric, is determined by the ratio of handgrip strength to skeletal muscle mass. Despite its potential significance, the association between MQI and circadian syndrome (CircS) has not been explored. This study aims to elucidate the potential association between MQI and CircS. In this study, a cross-sectional analysis was conducted on data from NHANES 2011-2014. And the association between MQI and CircS was explored through a range of statistical methods, including ROC curve analysis, multivariate logistic regression, RCS regression, and subgroup analysis. In this study, a cohort of 2250 American adults was enrolled, among whom 229 individuals (10.2%) were diagnosed with CircS. Both RCS and logistic regression analyses indicated a significant negative linear association between MQI and the prevalence of CircS (OR = 0.35, 95% CI = 0.26, 0.46), as well as its five components, including elevated FPG, elevated BP, elevated WC, reduced HDL, and depression. Subgroup analyses demonstrate that this independent association remained consistent across various demographics and lifestyle factors, including age, physical activity, gender, BMI, and alcohol abuse and smoking status. ROC analysis reveals that, compared to handgrip strength (HGS) and skeletal muscle mass, MQI (AUC = 0.713, 95% CI = 0.678, 0.747) serves as a more reliable factor for identifying CircS. The findings indicate a significant inverse association between MQI and CircS. Promoting physical exercise, especially resistance training, may mitigate the risk of CircS.