Waist circumference and waist-to-hip ratio may offer the most reliable gauge of cardiovascular risk
A landmark investigation tracking 260,000 individuals over two decades has concluded that measuring belly fat is a superior predictor of heart disease compared with body mass index alone.
The research, published yesterday in the Journal of the American College of Cardiology, found that waist circumference and waist-to-hip ratio offer a far more reliable gauge of cardiovascular risk than the widely used BMI metric.
The study revealed that individuals carrying excess fat around their midsection faced heightened dangers of heart attacks, strokes, heart failure and death — regardless of whether their BMI fell within a normal range.
BMI, which is derived by dividing weight by the square of height, fails to capture where fat accumulates in the body, the researchers determined.
Experts are now urging clinicians to incorporate waist measurements into standard cardiovascular assessments.
Participants were categorised according to their BMI alongside their waist circumference or waist-to-hip ratio, with researchers then tracking rates of various cardiac conditions and deaths.
Among those with a normal BMI, roughly five per cent had an elevated waist circumference, whilst 18 per cent displayed a high waist-to-hip ratio.
Approximately 40 per cent of overweight individuals had both wide waistlines and raised waist-to-hip ratios.
Strikingly, nine per cent of those classified as obese actually had smaller waistlines and 45 per cent recorded a low waist-to-hip ratio.
Normal-weight or overweight individuals with larger midriffs were between 15 and 50 per cent more likely to develop cardiovascular disease.
Conversely, obese participants with smaller waistlines showed no greater risk of cardiac events than normal-weight people with low waist circumference.
The study's authors warned that neglecting waist measurements and the build-up of central adiposity risks "misclassification" of cardiovascular disease risk.
Dr Zeina Dardari, the lead author from Johns Hopkins School of Medicine in Maryland, said: "Our findings emphasise the critical role of identifying elevated central adiposity, even in individuals with a normal BMI or with a BMI in the overweight range."
She added: "Relying solely on BMI may result in misclassification of cardiovascular risk across a wide range of cardiovascular outcomes."
Dr Michael Blaha, a senior author also at Johns Hopkins, stated that these measurements "reclassify risk defined by traditional BMI thresholds".
He noted: "We saw individuals with clinically determined normal weight who had elevated central adiposity and high waist-to-hip ratio, associating them with higher risk across most outcomes."
Prof Harlan Krumholz, who serves as editor-in-chief of JACC and is based at Yale School of Medicine, declared it was "time to abandon a sole focus on body mass index".
He described the research as "enormously important", noting it was "based on data from hundreds of thousands of participants in large-scale cohort studies" and that it "authoritatively shows that waist circumference and waist-to-hip ratio provide critical information about cardiovascular risk, even among people with a BMI considered normal".
Prof Krumholz was unequivocal in his prescription for clinical practice. "Where fat is distributed matters, and these simple measures should be part of routine cardiovascular risk assessment," he said.
The findings lend fresh weight to earlier research suggesting that the notion of being "fat but fit" may hold some validity — provided excess weight is not concentrated around the abdomen.
