Waist-to-Height Ratio More Accurate for Predicting Risk

• A new study suggests your body shape may reveal heart disease risk more accurately than BMI.
• Researchers found people with larger waists relative to their height were more likely to develop calcium buildup in their heart arteries — even if their BMI was in a healthy range.
• The findings could change how doctors screen for heart risk and provide patients with a simple at-home way to monitor their health.

Your body shape might better predict your risk of heart disease than your body mass index (BMI), according to a new study.

If you want a simple way to check your heart health, measure your waist and divide that number by your height. A waist-to-height ratio (WHtR) of 0.5 or higher could signal an increased risk of heart disease.

New research, recently published in The Lancet Regional Health, found that WHtR was more closely linked to heart disease risk than both BMI and waist circumference alone.

“I think we’ve been shifting away from BMI being the only idea that matters to waist-to-height ratio being better when it comes to cardiovascular outcomes, especially related to metabolic and atherosclerotic conditions,” said Marcio Sommer Bittencourt, MD, PhD, associate professor of cardiology at University of Pittsburgh and senior author of the research

Notably, the findings held true even among people with a BMI below 30, the threshold for clinical obesity.

In other words: people who were in the normal or overweight BMI range were still identified as having a risk for future heart disease based on their WHtR.

“For those with a BMI between 25 to 29.9 but also for those with normal BMI, waist-to-height ratio was a very important marker. Waist-to-height ratio identified individuals at higher risk for actual sclerosis development after five years even after adjustment for all classic cardiovascular risk factors,” said Thiago Bosco Mendes, MD, instructor of medicine at University of Pittsburgh and first author of the research.

Although the measurement is simple, it’s not yet a routine part of standard health screenings. WHtR could become a valuable tool for physicians to spot people at higher risk of heart disease — especially those whose BMI doesn’t reflect their true risk.

It’s also easy to do at home for anyone who wants to keep tabs on their health without stepping on a scale.

The researchers followed 2,721 adults in São Paulo, Brazil, to examine how body measurements predicted heart disease risk in comparison to BMI.

Participants were about 48 years old on average, and nearly two-thirds were female. The sample was racially diverse, but predominantly white (57%), and included participants of mixed race, Black, and Asian backgrounds.

To be included in the study, participants had to have no coronary artery calcium (CAC) buildup, as confirmed by a heart scan. CAC is a risk indicator for heart disease, with higher values indicating a more severe condition.

Alongside this initial heart scan, researchers performed three body measurements at baseline: BMI, waist circumference, and WHtR.

After a five-year follow-up, researchers once again measured CAC. Approximately 15% of participants exhibited signs of CAC buildup, and it was found to be more prevalent among those with larger waists.

Although all three measures — BMI, waist circumference, and WHtR — were associated with heart disease risk in an unadjusted analysis, only WHtR remained an independent predictor after accounting for traditional risk factors, such as high blood pressure, elevated cholesterol levels, and diabetes.

In patients with a WHtR of 0.5 or greater, about 18% had CAC buildup, compared to only 10% those with a WHtR of less than 0.5. For every moderate increase in waist size compared to height, the risk of developing calcium in the heart arteries went up by about 18%.

“This study helps us to see what we have always suspected, which is that those people who have greater metabolic dysfunction, in this case marked by a waist-to-height ratio, are more likely to develop cholesterol plaque,” said Yu-Ming Ni, MD, board certified cardiologist and lipidologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in California. Ni wasn’t involved in the research.

The risk posed by a larger WHtR wasn’t fully explained by other common metabolic issues, such as high blood pressure and blood sugar, suggesting that abdominal fat may be harmful to heart health in other ways.

That’s likely because WHtR shows the presence of visceral fat, which is stored in the abdominal cavity and is associated with an increased risk of cancer, heart disease, and diabetes.

“We know that those who have more visceral fat have more inflammation, and that’s a risk factor for atherosclerosis as well,” Mendes said.

Doctors have long relied on BMI, an estimate of body fat based on height and weight, to diagnose obesity, and as an indicator of risk for everything from heart disease to cancer.

It’s a straightforward calculation that has played a disproportionately significant role in healthcare and medical research. However, the question of whether BMI is an accurate predictor of health has been increasingly raised by patients and doctors alike.

Other measurements, such as waist circumference, waist-to-hip ratio, and WHtR, may be better predictors of certain health outcomes than BMI alone; however, they are not used nearly as frequently.

“Waist circumference measurement can be a little bit harder to do uniformly across clinic settings,” Ni said, “but it is something that I think the average person could use as a gauge of their personal health.”

Bittencourt emphasized that for some people — particularly those in the healthy or overweight BMI range — body measurements may offer a more accurate picture and better predict risk, especially among people who might otherwise be considered healthy.

Understanding your WHtR measurement may offer additional insight into your health in ways that BMI and weight alone do not. Still, for general wellness, BMI is generally a reliable indicator.

“Recommendations in terms of diet, exercise, reducing caloric intake, and preference for non-ultra-processed food are not changed by our findings,” Bittencourt said. “Whatever you can do to reduce your abdominal size, your WHtR, or your weight are still recommended.”