Associations of body roundness index with with all-cause mortality and cardiovascular diseases: the prospective urban rural epidemiology (PURE)-China study

Background To determine the impact of body roundness index (BRI) on cardiovascular disease (CVD) and mortality in Chinese adults. Methods The PURE-China study recruited 47,931 participants aged 35-70 years from 12 provinces of China between 2005 and 2009. The BRI was calculated based on height and waist circumference. The primary outcomes were major CVD events (stroke, myocardial infarction (MI), or heart failure (HF)), CVD mortality, and all-cause mortality. Cox proportional hazards frailty models and restricted cubic splines were used to analyze the associations between BRI and the primary outcomes. Results Among the 45,864 participants included in this study, we documented 2,659 deaths (including 960 CVD deaths) and 4,280 major CVD events (comprising 2,828 strokes, 1,134 MI, and 318 HF ) over a median follow-up of 11.9 years. In fully adjusted models, each standard deviation increment in BRI was associated with increased risks of major CVD events (HR=1.12, 95%CI: 1.04-1.20), stroke (HR=1.11, 95%CI: 1.07-1.16), and MI (HR=1.19, 95%CI: 1.12-1.27). Compared to the lowest BRI quartile, participants in the highest quartile exhibited significantly increased hazards of major CVD events (HR: 1.35; 95%CI: 1.21-1.51), stroke (HR: 1.32; 95%CI: 1.15-1.51), and MI (HR: 1.55; 95%CI: 1.25-1.92) in fully adjusted models. Restricted cubic spline analyses revealed J-shaped dose-response associations between BRI and major CVD events, myocardial infarction, as well as stroke, while U-shaped associations were observed for all-cause mortality and CVD mortality,with nadirs identified at BRI values of 3.27 and 3.01, respectively. These nonlinear relationships explained the non-significant associations in fully adjusted models when comparing the highest versus lowest BRI groups for all-cause mortality (HR: 0.96; 95%CI: 0.85-1.09) and CVD mortality (HR: 1.13; 95%CI: 0.91-1.41). In the low-BRI group, each SD increase was associated with reduced all-cause mortality (HR=0.86, 95%CI: 0.74-0.99) and CVD mortality (HR=0.82, 95%CI: 0.61-1.10). Conversely, in the high-BRI group, each SD increase predicted higher all-cause mortality (HR=1.15, 95%CI: 1.09-1.22) and CVD mortality (HR=1.27, 95%CI: 1.18-1.37). Conclusions BRI were significantly associated with the risk of CVD and mortality.