The association between body roundness index (BRI) in middle-aged adults and long-term all-cause mortality risk

Introduction The body roundness index (BRI) incorporates height and waist circumference (WC) and provides an estimate of both total body and visceral fat percentages. Since the development of BRI, several studies have demonstrated an association between higher BRI values and increased mortality, with most of these studies conducted in West Asian populations. Purpose We examined the association between BRI and all-cause mortality in a nationwide sample of Israeli adults. Several studies investigated this association, but none was based on Israeli population. An additional significant strength of this study is its large sample size and the availability of long-term follow-up data spanning approximately 20 years, on a representative population sample. Materials and Methods Data were collected from the First Israeli National Health and Nutrition Survey (‘MABAT’), conducted between 1999 and 2001. Participants aged 25–64 (n=2,274) were followed for 21.4 years for mortality, during which 251 deaths occurred. Height, weight, and WC were measured at baseline, enabling BRI and body mass index (BMI) calculation. Further data on sociodemographic characteristics and established cardiovascular risk factors were obtained. To estimate mortality risk, Cox proportional hazards regression models were constructed, adjusting for potential confounders, and spline regressions were used. Additional analyses estimated mortality risk across joint BMI-BRI categories. Results The sample [mean (SD) age, 43 (11) years] included 1,126 (49.5%) females. Mean (SD) values were 26.8 (4.8) for BMI and 4.34 (1.64) for BRI. Spline regression analysis demonstrated a J-shaped association between BRI and mortality (Fig. 1). After adjustment for sociodemographic and cardiovascular risk factors, increased hazard ratios (HRs) were observed in the fourth (2.27; 95% CI: 1.47-3.51) and fifth (2.40; 95% CI: 1.56-3.69) quintiles compared with the middle quintile. Analyzed as a continuous variable, the multivariable-adjusted HR was 1.24 (95% CI: 1.10-1.40) per 1 SD increase in BRI; restricting the cohort to participants with a BMI <30 kg/m2 yielded a HR of 1.27 (95% CI: 1.10-1.46). Compared with the low BMI-low BRI reference group, high BMI with normal BRI was not associated with an increased mortality, whereas normal BMI with high BRI showed a substantial elevation in risk (Fig. 2). Conclusion BRI was associated with all-cause mortality, demonstrating a J-shaped relationship. Importantly, even among participants classified as non-obese by BMI, higher BRI values were independently linked to an increased mortality risk, suggesting BRI may be a promising anthropometric risk factor beyond BMI.Figure 1Figure 2