A body shape index and cardiometabolic risk markers: age- and sex-specific patterns

Visceral adiposity is a key determinant of cardiometabolic risk, yet Body Mass Index (BMI) does not adequately capture differences in fat distribution across age and sex. A Body Shape Index (ABSI), derived from waist circumference, height, and weight, was developed to better reflect abdominal adiposity independent of overall body size. This study examined sex- and age-specific patterns of ABSI and its independent associations with cardiometabolic risk markers beyond BMI.

This cross-sectional study included 1248 adults from the National Health Survey. Participants were stratified by sex and age (<45, 45-59, and ≥60 years). Standardized anthropometric, blood pressure, fasting glucose, and lipid measurements were obtained. Multivariable regression models evaluated associations between ABSI and cardiometabolic conditions, adjusting for BMI and lifestyle factors.

ABSI increased significantly with age in both sexes (p < 0.001), with a more pronounced rise among women after midlife. No sex differences were observed before age 45; however, in contrast to other population studies, women aged ≥60 years had higher ABSI than men (0.0859 ± 0.0059 vs. 0.0820 ± 0.0055; p = 0.02). Higher ABSI was independently associated with hypertension (OR 1.38; 95% CI 1.16-1.64) and dyslipidaemia (OR 1.29; 95% CI 1.08-1.54). ABSI was not independently associated with hypertriglyceridaemia, low HDL cholesterol, or high fasting glucose.

ABSI captured age- and sex-specific differences in central adiposity, remaining independently associated with hypertension and dyslipidaemia. The higher ABSI in older Brazilian women compared with men underscores population-specific body composition trajectories and the need for further research across diverse settings.