Association Study of Body Roundness Index Trajectories with the Risk of Diabetes in Middle-aged and Older Adults

Objective : This study examines whether changes in the Body Roundness Index (BRI—a value derived from height and waist circumference that quantifies body shape) predict diabetes in middle-aged and older Chinese adults. Methods: We evaluated data from 5,108 participants in the China Health and Retirement Longitudinal Study (CHARLS) (2011–2023). Group-based trajectory modeling (GBTM—a statistical approach for clustering individuals by change patterns over time) identified BRI trends from 2011 to 2016. Diabetes diagnoses from 2017 to 2023 were the measured outcome. Univariate and multivariate logistic regression (statistical methods for quantifying disease risk) assessed the association between identified BRI patterns and diabetes. Results : Three BRI trajectories were identified: low-stable (47.02%), medium-stable (42.68%), and high-stable (10.30%). Compared with the low-stable group, the medium-stable (OR = 2.11, 95% CI: 1.70–2.60) and high-stable (OR = 4.10, 95% CI: 3.13–5.37) patterns were associated with a higher risk of diabetes. Multivariate findings supported these results. Conclusion : Medium- and high-stable BRI patterns robustly forecast diabetes risk in this population.