Body shape index in comparison with other anthropometric measures in prediction of total and cause-specific mortality

Background: The association of body mass index (BMI) with mortality remains controversial among the middle-aged and elderly. Moreover, the contribution of other anthropometric measures to predict mortality is unclear.

Methods: We assessed the association of BMI, waist circumference (WC), waist-to-height ratio (WHtR), waist-to-hip ratio (WHR) and a body shape index (ABSI=WC/(BMI(2/3)×height(1/2))) with total, cardiovascular and cancer mortality by using Cox proportion hazard models among 2626 men and 3740 women from the prospective population-based Rotterdam Study. Predictive performance was assessed through informativeness, c-statistic, integrated discrimination improvement (IDI), and continuous net reclassification improvement (cNRI).

Results: During 22 years of follow-up, 3675 deaths from all-causes, 1195 from cardiovascular disease, and 873 from cancer occurred. In the multivariable model, ABSI showed a stronger association with mortality compared with BMI, WC, WHtR and WHR. HRs and CIs (95% CIs) for total mortality per 1 SD increase in ABSI were 1.15 (1.09 to 1.21) for men and 1.09 (1.04 to 1.14) for women. For cardiovascular and cancer mortality, these HRs (95% CI) were 1.18 (1.08 to 1.29) and 1.10 (0.99 to 1.22) for men, 1.04 (0.96 to 1.12) and 1.18 (1.07 to 1.30) for women, respectively. The models including ABSI did not increase the c-statistics. Among men, in prediction of total mortality the model including ABSI was more informative (χ(2)=26.4) and provided improvement in risk stratification (IDI 0.003, 95% CI 0.001 to 0.005; cNRI 0.13, 95% CI 0.06 to 0.21).

Conclusions: In our population-based study, among different anthropometric measures, ABSI showed a stronger association with total, cardiovascular and cancer mortality. However, the added predictive value of ABSI in prediction of mortality was limited.