Non-linear associations and threshold effects of BRI, CI, and WHtR with grip strength in U. S. adults aged ≥20 years: a cross-sectional study

In U. S. adults, BRI, CI, and WHtR exhibited non-linear and threshold-dependent associations with grip strength, suggesting that these indices can help refine the assessment of muscle strength. The findings indicate that integrating these indices could enhance the accuracy of risk stratification for muscle dysfunction, particularly in individuals with central obesity. Longitudinal studies are needed to further validate the causal relationships underlying these associations.