Association between body roundness index trajectories and successful aging among older adults in China: A nationally representative longitudinal cohort study

BACKGROUND: Successful aging involves maintaining physical vitality, emotional health, and meaningful social connections throughout late life. Body Roundness Index (BRI), a numerical indicator of body shape, is drawing growing interest as a potential marker for evaluating successful aging. Drawing on data from the China Health and Retirement Longitudinal Study (CHARLS), this research examined how BRI trajectory patterns were associated with successful aging in the older Chinese population. METHODS: The analysis included 2517 individuals aged 60 and above, drawn from the CHARLS cohort. BRI was measured in 2011, 2013, and 2015, and its longitudinal patterns were determined through group-based trajectory modeling (GBTM). Successful aging was assessed at the 2018 follow-up. To investigate the link between BRI trajectories and successful aging, we employed binary logistic regression, supplemented by subgroup and interaction analyses to test for effect modification. FINDINGS: Three distinct BRI trajectories were identified: low-stable (46.9 %), intermediate-stable (43.0 %), and high-rising (10.1 %). The intermediate-stable group had the greatest odds of successful aging compared to the high-rising group, followed by the low-stable group with a moderately lower likelihood. Upon controlling for a range of covariates, individuals in the intermediate-stable group and the low-stable group had significantly greater odds of successful aging, with ORs of 2.63 (95 % CI: 1.45-5.12, P = 0.002) and 2.52 (95 % CI: 1.26-5.31, P = 0.012), respectively. Across sensitivity analyses, the intermediate-stable trajectory showed the strongest and most consistent association with successful aging. CONCLUSION: This study highlights the need to monitor body changes in older adults and develop targeted health strategies to support successful aging.