Independent and joint associations of healthy lifestyle and phase angle with musculoskeletal phenotypes: a large-scale population-based study

Evidence linking lifestyle and phase angle (PhA) to co-occurring muscle and bone abnormalities remains limited. We examined their independent and joint associations with muscle and bone phenotypes in Han Chinese adults. This cross-sectional study included 21,340 adults from the China National Health Survey. PhA was measured using multifrequency bioelectrical impedance analysis and bone status using calcaneal quantitative ultrasound (QUS). Low muscle strength was defined using Sarcopenia Definitions and Outcomes Consortium handgrip cutoffs and low bone status using a QUS-derived T-score < − 1.0; co-occurrence required both. The lifestyle score incorporated smoking, alcohol consumption, physical activity, and diet. Multivariable logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs) for a four-component lifestyle score and sex-specific PhA quartiles. High versus low lifestyle scores were associated with lower odds of low muscle strength (OR = 0.69, 95% CI: 0.61–0.77), QUS-defined low bone status (0.76, 0.70–0.83), and co-occurrence (0.56, 0.46–0.67). For co-occurrence, ORs comparing the highest with lowest PhA quartile were 0.39 (95% CI: 0.27–0.57) in men and 0.82 (0.57–1.16) in women, without significant sex interaction (P = 0.560). Sex interactions were observed for low muscle strength (P = 0.004) and QUS-defined low bone status (P < 0.001). Participants with both high lifestyle scores and high PhA had the lowest odds of co-occurrence (OR = 0.33, 95% CI: 0.24–0.46). Higher lifestyle scores and PhA were associated with lower odds of adverse muscle and bone phenotypes. Their joint assessment warrants further investigation in longitudinal studies. Not applicable. The co-occurrence of adverse muscle- and bone-related phenotypes imposes a substantial burden in aging populations, yet the combined associations of lifestyle and phase angle (PhA) remain underexplored. This large-scale population-based study found that a higher healthy lifestyle score and higher PhA were independently and jointly associated with lower odds of co-occurring low muscle strength and QUS-defined low bone status. These findings support further investigation of lifestyle patterns and PhA in relation to concurrent muscle and bone health.