Take a tape measure to your waist. If the number in inches is more than half your height in inches, your heart may be at higher risk of disease, even when the scale and your BMI say you are fine.
That is the conclusion of a longitudinal study of 2,721 adults published on October 31, 2025 in The Lancet Regional Health - Americas.
Led by researchers at the University of Pittsburgh working with data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), the analysis found that waist-to-height ratio was the only body measurement that independently predicted new coronary artery calcification over a follow-up averaging just over five years.
Coronary artery calcification is calcium buildup in the arteries feeding the heart, and it is one of the earliest visible signs that atherosclerosis is developing.
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Why BMI kept missing the risk
Body mass index divides weight by the square of height. It captures overall size, but it does not know where the fat is stored.
Two people with the same BMI can carry very different amounts of visceral fat, the deep abdominal fat that wraps around the liver, pancreas and intestines and drives metabolic and vascular damage.
Waist-to-height ratio, or WHtR, tries to capture that. You divide waist circumference by height, both in the same unit. A value above 0.5 is the common threshold for central obesity.
In the Brazilian cohort, WHtR of 0.5 or higher was tied to a coronary artery calcification incidence of 18.2 percent, compared with 9.8 percent below that cutoff.
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The effect was strongest in people whose BMI was below the traditional obesity line of 30. In participants with a BMI under 25, each standard-deviation increase in WHtR more than doubled the odds of new calcification.
The number to measure at home
Measuring is straightforward. Wrap a tape measure horizontally around your bare midsection, roughly at the level of the belly button and just above the top of the hip bones.
Breathe out normally. Divide that number by your height in the same unit.
Above 0.5, current guidance treats the reading as a marker of increased central adiposity. The UK's National Institute for Health and Care Excellence advises adults with a BMI under 35 to use waist-to-height ratio alongside BMI, with 0.5 to 0.59 flagged as increased central adiposity and 0.6 or higher as high central adiposity, both linked to elevated risk of type 2 diabetes, high blood pressure and cardiovascular disease.
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Belly fat, inflammation and the heart
The Pittsburgh analysis lines up with other recent evidence that abdominal fat matters more than the scale suggests.
Research presented at the American Heart Association's EPI|Lifestyle Scientific Sessions 2026 in Boston followed nearly 2,000 Black adults in Jackson, Mississippi. Higher waist circumference and higher waist-to-height ratio were tied to greater heart failure risk, while BMI alone was not. Inflammation appeared to explain roughly a quarter to a third of the link.
The American Heart Association reached a similar conclusion in an earlier scientific statement, noting that people with abdominal obesity can face increased heart disease risk even when their BMI sits in the healthy range, and that waist circumference has been shown to predict cardiovascular death independent of BMI.
None of this replaces a clinical checkup. Blood pressure, cholesterol, blood sugar and family history remain part of the picture, and anyone whose reading raises concern should discuss it with their doctor rather than start their own treatment plan. But a tape measure and a calculator give a useful early signal that a bathroom scale cannot.
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