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

Mary Anne Nascimento-Souza,Juliana Vaz De Melo Mambrini,Maria Fernanda Lima-Costa,Sérgio Viana Peixoto

doi:10.1590/0102-311x00016020

Mary Anne Nascimento-Souza, Juliana Vaz De Melo Mambrini + Show 2 more

Open Access

https://doi.org/10.1590/0102-311x00016020

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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.

Highlights

Previous studies have shown the relationship between overweight and obesity and the risk of mortality from cardiovascular disease, cancer and all-cause [1,2]
The medians of a body shape index (ABSI), Waist circumference (WC), waist-to-height ratio (WHtR) and body mass index (BMI) were significantly higher among women (0.0856m11/6kg-2/3, 92cm, 0.60 and 25.65kg/m2, respectively) than among men (0.0841m11/6kg-2/3, 89.50cm, 0.54 and 23.66kg/m2, respectively) (p < 0.05)
For BMI evaluated with common cut-off points, we found that underweight older adults had a higher risk of mortality (HR = 1.42, 95% confidence intervals (95%CI): 1.11-1.80), while being overweight was a protective factor (HR = 0.82, 95%CI: 0.69-0.99), even after adjustment for WC or ABSI (Table 3)

Summary

Introduction

Previous studies have shown the relationship between overweight and obesity and the risk of mortality from cardiovascular disease, cancer and all-cause [1,2]. Most prospective studies assessing the association between overweight and mortality risk used the body mass index (BMI) to evaluate nutritional status 3. Applied to predict the risk of different health events related to overweight or obesity, its use has been questioned, as BMI does not distinguish between the accumulation of lean or fat mass or the distribution of adipose tissue 4, i.e., a high BMI may not necessarily reflect an increase in adiposity. BMI validity as an adiposity indicator in older adults is limited 5, as lean mass decreases with aging even without a change in body weight 6. The high correlation between WC and BMI hinders determining the independent role of general and abdominal fat as a risk factor for health outcomes [10,11]

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