Association Between Body Roundness Index and Sarcopenia in Older Adults: Evidence from a Prospective Cohort Study Using CHARLS

Objective: This study aimed to investigate the association between the Body Roundness Index (BRI) and the risk of sarcopenia in older adults. Methods: A total of 2,798 individuals aged 60 years and older without sarcopenia at baseline were drawn from the China Health and Retirement Longitudinal Study (CHARLS). We investigated the relationship between BRI and sarcopenia using logistic regression analysis. Subgroup analysis was conducted to explore the association between BRI and sarcopenia risk across different groups. Additionally, restricted cubic spline (RCS) and threshold effect analyses were conducted to characterize the potential nonlinear association. Results: Over a median follow-up of two years, 358 participants (12.8%) developed sarcopenia. Quartile-based analysis revealed a significant inverse association between BRI and sarcopenia risk. After adjusting for confounders, individuals in the highest BRI quartile (Q4) exhibited a markedly lower likelihood of developing sarcopenia compared to the lowest quartile (Q1) (OR = 0.03, 95% CI: 0.02–0.06). RCS analysis indicated an L-shaped nonlinear association, with an inflection point at 4.461. The relationship between BRI and sarcopenia risk remained significant on both sides of this threshold. Furthermore, subgroup analysis did not indicate any significant interaction effects between BRI and sarcopenia risk (P for interaction > 0.05). Conclusion: This study suggests a significant negative association between BRI and the risk of sarcopenia, highlighting BRI as a potentially valuable indicator for assessing sarcopenia risk in older adults.