Association of muscle quality index with osteoarthritis in young and middle-aged American adults

PurposeDecreased muscle mass was a risk factor for osteoarthritis (OA). It could be more accurately assessed by muscle quality index (MQI), which considered arm or appendicular skeletal muscle mass (ASM) and handgrip strength (HGS). We aimed to evaluate association between MQI and OA in aged 20-59 American adults.Materials and methodsThis cross-sectional analysis included 4,491 participants (aged 20-59) from 2011 to 2014 NHANES. HGS and ASM were evaluated by hand dynamometer and DXA. MQItotal was calculated by HGS/ASM (kg/kg). OA was self-reported. Multivariate logistic regression and RCS were used to evaluate the association between MQItotal and OA. Discriminatory capability and clinical utility were evaluated by ROC and DCA curves.ResultsWeighted data were representative of approximately 7 million US young and middle-aged adults diagnosed with OA (mean age 48.59 years, female 60.68%). There was a 28% decrease in OA for every 1-unit increase in MQItotal [OR (95% CI): 0.72 (0.53, 0.97)] after fully adjustment. Compared to extremely low group, normal MQItotal was associated with almost 50% lower OA [0.54 (0.36, 0.82)]. No significant interaction was observed in subgroup analysis. RCS indicated that the association was non-linear (non-linearity P = 0.027). ROC analysis demonstrated that MQItotal could effectively predict OA (AUC = 0.801) in fully adjusted model, and DCA displayed threshold exceeding over 40%, providing high clinical practicability.ConclusionIn summary, low muscle mass index could indicate risk for OA patients. Early detection of muscle decline in OA is vital, as muscle weakness can lead to serious outcomes. Targeted enhancement of muscle mass may help reduce OA prevalence.