Association of Anthropometric Obesity Measurements with Ischemic ECG Changes and 20-Year All-Cause and Cardiovascular Mortality in Community Dwelling Older Adults

Background: Central obesity is strongly associated with cardiovascular morbidity and mortality, yet inadequately represented by body mass index (BMI). Anthropometric markers better reflecting central obesity have been proposed, but their comparative effectiveness in predicting mortality among the elderly remains underexplored.

Methods: 963 older adults from the Glucose Intolerance, Obesity, and Hypertension study, were followed for up to 13 years. Nine different baseline obesity markers were evaluated, focusing on their cross-sectional association with ischemic changes on ECG, and long-term cardiovascular and all-cause mortality. Multivariable regression models were used for analysis, and performance was assessed using receiver operating characteristic (ROC) curves and net reclassification improvement (NRI) analysis.

Results: Mean age was 72.3 ± 7 years and 471 (49%) were females. Upper quantiles (Q4-5) of waist-to-height ratio (WTHR) (OR=2.0, 95%CI:1.2-3.2, p=0.01), weight-adjusted waist index (WWI) (OR=1.8, 95%CI:1.1-2.9, p=0.01) and body roundness index (BRI) (OR=2.0, 95%CI:1.2-3.2, p=0.01) were associated with higher odds for ischemic changes on ECG. During follow-up, 466 (48.4%) participants died, including 179 (38.4%) from cardiovascular causes. The WWI was the strongest predictor of both all-cause (HR=1.4, 95%CI:1.1-1.7, p=0.002) and cardiovascular mortality (HR=1.7, 95%CI:1.2-2.3, p=0.0031). ROC analysis showed better predictive ability for WWI (AUC=0.442, 95%CI:0.4-0.5, p=0.003), while NRI analysis revealed that WWI outperformed other markers, correctly reclassifying 36% (95%CI: 0. 2-0.5, p=0.01) and 32% (95%CI: 0.1-0.5, p<0.001) of participants for all cause and cardiovascular mortality respectively compared with BMI-based model and 35% (95%CI: 0.2-0.5, p=0.01) and 31% (95%CI: 0.1-0.5, p<0.001) for both outcomes respectively, compared with model unadjusted for any marker.

Conclusions: Among the various obesity markers, the WWI showed the strongest association with both all-cause and cardiovascular mortality while outperforming BMI in predicting all-cause and cardiovascular mortality. WWI should be considered as a preferred marker for risk stratification in individuals with abnormal weight, potentially replacing BMI.