Associations of longitudinal trajectories in body roundness index with mortality and cardiovascular outcomes: a cohort study

The body roundness index (BRI) is a new anthropometric index that combines height and waist circumference to predict the percentages of total and regional fat. The longitudinal trajectories of BRI can reflect the long-term pattern of BRI changes; however, their effects on the incidence of cardiovascular disease (CVD) and mortality are poorly characterized.Our aim was to identify BRI trajectories and to estimate their associations with mortality and incident CVD events.This study included a total of 59,278 participants (mean age, 54.8 years) free of malignant tumors and CVD and with repeated measurements of BRI from 2006 to 2012. The BRI trajectories from 2006 to 2012 were identified using the latent mixture model. A Cox proportional hazards model was used to analyze the associations between BRI trajectories and the risk of CVD events and mortality.We grouped the BRI trajectories into 4 distinct groups during 2006-2012: low-stable (mean BRI = 2.7), moderate-stable (mean BRI = 3.7), moderate-high-stable (mean BRI = 4.7), and high-stable (mean BRI = 5.8). We identified 1928 CVD events and 2928 deaths during the follow-up. After adjustment for potential confounders, compared with the low-stable group, the HRs of CVD were 1.37 (95% CI: 1.19-1.58) for the moderate-stable group, 1.64 (95% CI: 1.40-1.91) for the moderate-high-stable group, and 2.03 (95% CI: 1.64-2.52) for the high-stable group. We observed similar associations for myocardial infarction and ischemic stroke. The association between BRI trajectories and CVD was more prominent in subjects aged <55 years.BRI trajectories were significantly associated with the risk of CVD, and the association was more evident in younger adults.