Waist Size Beats BMI at Flagging Heart Disease Risk, 260K-Person Study Finds

A study in JACC, the American College of Cardiology’s flagship journal, argues that BMI alone misclassifies cardiovascular risk because it ignores where body fat sits. Drawing on data from more than 260,000 people tracked for roughly 20 years through the Cross-Cohort Collaboration, researchers found that waist circumference (WC) and waist-to-hip ratio (WHR) — simple measures of central adiposity — reclassify the risk that BMI thresholds assign.

The reclassification cuts both ways. People rated normal-weight or overweight by BMI but carrying high WC or WHR showed 15% to 50% greater risk across most of nine cardiovascular outcomes, including heart attack, stroke, heart failure, and cardiovascular mortality. Conversely, people classed as obese by BMI but with a low waist measurement showed no significantly elevated risk versus normal-weight peers, and actually had lower all-cause mortality. The signal held even among those whose BMI looked unremarkable.

The authors and JACC’s editor-in-chief frame this as a case for retiring BMI as a standalone screen and folding waist measurements into routine cardiovascular risk assessment. Caveats: the study lacked data on physical activity, diet, and genetic obesity risk, and relied on a single waist/hip measurement, so it can’t speak to how shifting central fat over time changes risk.