Association between “a body shape index” and mortality: Bambuí Cohort Study of Aging, Brazil

Abstract

This article aims to evaluate the joint and separate association between abdominal and general adiposity indicators and mortality. Data was collected from 1,366 older adults in the Bambuí Cohort Study of Aging with complete information for all variables of interest. The outcome variable was all-cause time until death; exposure variables were a body shape index (ABSI), waist circumference (WC), waist-to-height ratio (WHtR) and body mass index (BMI), assessed at the beginning of the study, and at the 3rd, 5th and 11th year of follow-up. Association between the quartiles of anthropometric indicators and mortality was calculated using an extended Cox proportional hazards model and adjusted for socioeconomic and behavioral confounding factors. Older adults in the 4th ABSI quartile had a higher risk of mortality regardless of BMI (1.27; 95%CI: 1.01-1.58), but this association was not observed in sensitivity analyses. Older adults in the 2nd, 3rd and 4th BMI quartiles had a lower risk of mortality, even when adjusted for WC or ABSI. WC and WHtR showed no association consistent with all-cause mortality after adjustment for confounding factors. Considering the loss of significance in the sensitivity analyses, ABSI’s predictive capacity for mortality is still weak. Thus, adopting ABSI in clinical practice or in epidemiological surveys, in conjunction or replacing BMI and WC, requires more in-depth studies.