Beyond BMI: central obesity measures and cardiovascular risk in late life

In older adults, age-related changes in body composition may limit the predictive value of traditional obesity measures such as body mass index (BMI). The "obesity paradox," in which higher BMI appears protective, further complicates cardiovascular risk stratification in this population.

To assess the predictive value of various anthropometric indices for ischemic heart disease (IHD) in older adults.

This cross-sectional observational study included 1174 community-dwelling adults aged ≥ 65 years evaluated at the university geriatrics outpatient clinic. Anthropometric measures included BMI, waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body adiposity index (BAI), relative fat mass (RFM), body fat percentage, and skeletal muscle mass. Multivariate logistic regression analyses were conducted to assess associations with IHD. Receiver operating characteristics (ROC) curve analyses were used to assess discriminatory power.

The mean age was 75.6 ± 6.9 years; 68.8% were female. IHD was present in 20.3% of participants. WHR(OR = 1.839; 95% CI:1.255-2.695; p = 0.002), WHtR (OR = 1.746; 95% CI:1.250-2.437; p = 0.001), WC (OR = 1.463; 95% CI:1.060-2.020; p = 0.021), and RFM (OR = 1.740; 95% CI:1.257-2.408; p = 0.001), were independently associated with IHD, while BMI, BAI and fat percentage were not. WHR (AUC = 0.611, p < 0.001), WHtR (AUC = 0.561, p = 0.005), and RFM (AUC = 0.555, p = 0.010) demonstrated significant discriminatory performance.

In this geriatric cohort, central obesity measures such as WHR, WHtR and RFM appeared to be more predictive of IHD than BMI. However, the modest discriminatory ability observed suggests these indices may be more valuable when incorporated into multifactorial cardiovascular risk models rather than as standalone screening tools. While BMI's limitations in older adults are increasingly recognized, our findings provide direct comparative evidence supporting the clinical utility of fat distribution measures in cardiovascular risk assessment.

These findings support the use of fat distribution indices as part of comprehensive cardiovascular risk assessment in older adults.