New Delhi: While obesity is a known risk factor for heart disease, a new study showed that the ratio of a person's waist measurement compared to their height is more reliable than body mass index (BMI) at predicting the risk. 

The finding, published in The Lancet Regional Health-Americas, could reshape how clinicians and the public assess cardiovascular risk, especially for people who don't meet the classic definition of obesity.

"Higher BMI, waist circumference, and waist-to-height ratio at baseline were all associated with higher risk of developing future cardiovascular disease -- until we adjusted for other classic risk factors, such as age, sex, smoking, exercise, diabetes, hypertension, and cholesterol," said lead author Thiago Bosco Mendes, from the University of Pittsburgh, US

"When we did that, only waist-to-height ratio held as a predictor," Mendes said.

Also read: Explained: Why obesity’s effects vary from person to person

Researchers analysed data from 2,721 adults who had no cardiovascular disease at baseline and were followed for more than five years.

Much of that predictive power is concentrated among individuals with a BMI under 30, which is below the classic threshold for obesity, who may not realise they are at risk for cardiovascular disease.

BMI doesn't account for fat distribution or distinguish between harmful, visceral fat and protective, subcutaneous fat.

By contrast, waist-to-height ratio (WHtR), calculated by dividing waist circumference by height, directly reflects central obesity, which is more closely linked to heart disease.

That means that people with a BMI lower than 30, but a WHtR over 0.5, may be at higher risk of future coronary artery calcification, a key marker of cardiovascular disease, even in the absence of other risk factors, the study showed.

"Using waist-to-height ratio as a cardiovascular screening tool could lead to earlier identification and intervention for at-risk patients who might otherwise be missed," said senior author Marcio Bittencourt, Associate Professor of Medicine at Pitt.

"It's a simple and powerful way to spot heart disease risk early, even if a patient's weight, cholesterol, and blood pressure all seem normal," Bittencourt added. (IANS)