U-shaped relationship between body roundness index and osteoarthritis risk among middle-aged and older Chinese adults: a cross-sectional analysis.

A U-shaped association exists between BRI and osteoarthritis risk, with higher OA risk at both low and high extremes of BRI relative to an inflection point.

• Data were obtained from 8803 participants in the China Health and Retirement Longitudinal Study (CHARLS)
• Weighted logistic regression analysis and smoothed curve fitting both demonstrated the U-shaped pattern
• Both low and high BRI values were associated with increased OA risk compared to intermediate values
• The association was identified using smoothed curve fitting techniques to visualize nonlinear relationships

Women exhibited a stronger association between higher BRI and OA risk compared with men.

• OR for men: 1.01 (95% CI 0.86–1.06)
• OR for women: 1.07 (95% CI 1.03–1.11)
• Lower BRI values appeared to be more protective among women
• Gender was identified as a significant modifier of the BRI-OA relationship

Ethnicity modified the BRI-osteoarthritis relationship, with minority populations demonstrating higher optimal BRI values compared with Han Chinese populations.

• Stratified analyses were conducted across different subgroups including ethnicity
• Minority populations showed higher optimal (inflection point) BRI values compared with Han Chinese populations
• No significant modifying effects were identified for factors beyond gender and ethnicity

BRI was proposed as a more precise measure of overall and visceral adiposity compared with traditional anthropometric indices for assessing OA risk.

• BRI has been proposed as a more precise measure of overall and visceral adiposity compared with traditional indices
• The study highlights the importance of monitoring visceral adiposity as a modifiable factor in OA risk management
• BRI may serve as a practical tool for identifying individuals at elevated risk for osteoarthritis
• The potential association between BRI and OA risk had not been fully elucidated prior to this study

The cross-sectional study used logistic regression with stratified analyses to evaluate the BRI-OA association in 8803 middle-aged and older Chinese adults.

• Sample size: 8803 participants from CHARLS
• Study design: cross-sectional analysis
• Analytical methods included weighted logistic regression and smoothed curve fitting
• Stratified analyses were conducted across different subgroups including gender and ethnicity