Relationship between weight-adjusted waist index and handgrip strength in adults aged 50 and older in the United States: a cross-sectional study.

Abstract Background: Body muscle mass and strength have established links with obesity, but the association between weight-adjusted waist index (WWI) and combined handgrip strength remains largely unexplored. This study aims to examine the relationship between combined grip strength and WWI in individuals aged 50 and above. Methods: We utilized data from the National Health and Nutrition Examination Survey (NHANES) from 2011 and 2014. Multivariate logistic and linear regression models, generalized additive models, and fitted smoothing curves were employed to investigate the association between WWI and combined grip strength. Results: Our analysis of 4,179 eligible participants demonstrated a significant inverse relationship between grip strength and WWI. Subgroup analysis stratified by gender revealed a significant negative association between combined grip strength and WWI for both men and women. However, a saturation effect was observed in men, with an inflection point at 13.40 (cm/√kg). Conclusion: The present study highlights a negative association between combined grip strength and WWI in individuals over 50 years of age, with the relationship being particularly influenced by men (inflection point: 13.40 cm/√kg).