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Abdominal fat predicts heart disease risk better than BMI

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A study published in JACC, the flagship journal of the American College of Cardiology (ACC), found that adding waist circumference (WC) and waist-to-hip ratio (WHR) to body mass index (BMI) gives a more accurate picture of a person's cardiovascular disease risk than BMI alone. The finding comes from the Cross Cohort Collaboration, which analyzed data from more than 260,000 people followed for an average of 20 years. Researchers tracked at least one of nine outcomes for each participant: fatal and non-fatal heart attack, fatal and non-fatal stroke, heart failure, atrial fibrillation, total coronary heart disease, total cardiovascular disease, coronary heart disease mortality, cardiovascular disease mortality, and all-cause mortality. The American College of Cardiology announced the results in a press release dated August 11, 2026.

BMI, calculated by dividing weight in kilograms by height in meters squared, cannot capture where fat sits on the body. Central adiposity, the buildup of both visceral and subcutaneous fat around the abdomen, has previously been linked to chronic disease, while fat stored just under the skin has not shown as strong a link. The new study found that BMI categories often disagree with waist-based measurements: among people classified as normal weight by BMI, 5% had a high waist circumference and 18% had a high waist-to-hip ratio. Among people classified as overweight, those shares rose to 39% and 40%. Among people classified as having obesity, 9% actually had a low waist circumference and 45% had a low waist-to-hip ratio.

Those mismatches carried real risk differences. People with a normal or overweight BMI who also had a clinically high waist circumference or waist-to-hip ratio faced a 15% to 50% greater risk across most of the nine outcomes studied. The reverse pattern also held: people classified as having obesity by BMI but with a low waist circumference did not show a significantly different risk for most outcomes compared with normal-weight people who also had a low waist circumference. The one exception was all-cause mortality, which was significantly lower in that low-waist-circumference group with obesity.

"Indeed, it appears that WC and WHR reclassify risk defined by traditional BMI thresholds," said Michael J. Blaha, the study's senior author and director of clinical research at the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease. Lead author Zeina A. Dardari said the findings show that clinicians should weigh central adiposity across the whole BMI range, not only in people already flagged as overweight or having obesity. Harlan M. Krumholz, JACC's editor-in-chief, called it "enormously important" and said waist circumference and waist-to-hip ratio "should be part of routine cardiovascular risk assessment." The authors note the study did not include data on physical activity, diet or genetic obesity risk, and measured each participant's waist circumference and waist-to-hip ratio only once, which limits what it can say about how changes in central fat over time affect cardiovascular risk.

Key facts

  • Researchers with the Cross Cohort Collaboration followed more than 260,000 people for an average of 20 years, tracking waist circumference, waist-to-hip ratio and nine cardiovascular and mortality outcomes; the results were published in JACC and announced by the American College of Cardiology on August 11, 2026.
  • Among people with a BMI-defined normal weight, 5% had a high waist circumference and 18% had a high waist-to-hip ratio; among those classified as overweight, the shares were 39% and 40%.
  • Normal-weight or overweight people who also had a high waist circumference or waist-to-hip ratio faced a 15% to 50% greater risk across most of the nine outcomes studied.
  • People classified as having obesity by BMI but with a low waist circumference showed no significantly different risk for most outcomes versus normal-weight, low-waist-circumference people, except for a significantly lower all-cause mortality risk.
  • The study did not measure physical activity, diet or genetic obesity risk, and recorded each participant's waist circumference and waist-to-hip ratio only once.

Why it matters

BMI is still the default metric doctors and public health guidelines use to flag cardiovascular risk, but it says nothing about where on the body a person's fat sits. This study adds one of the largest and longest-running datasets yet to the case against relying on BMI alone: across more than 260,000 people followed for an average of 20 years, a meaningful share of people with a normal or overweight BMI carried elevated central fat, and that group faced 15% to 50% greater risk across most of the nine cardiovascular outcomes tracked. JACC's editor-in-chief endorsed the conclusion directly, arguing that cardiology should move past a sole focus on BMI.

Who it affects

The people most likely to be miscategorized are those near the normal or overweight BMI boundary who happen to carry extra fat around the waist: the study found a high waist circumference in 5% of normal-weight and 39% of overweight participants, and a high waist-to-hip ratio in 18% and 40% respectively. It also affects people classified as having obesity by BMI but with a low waist circumference, a group whose risk for most outcomes looked no different from normal-weight peers with a low waist circumference. More broadly, it targets clinicians and the primary-care and public-health systems that still use BMI thresholds as the first, and often only, cardiovascular screening step.

How to use it

The study's lead author, Zeina A. Dardari, frames the takeaway as a change in clinical practice: measure central adiposity across the whole BMI range, not only in people already classified as overweight or having obesity. In practice, that means adding a waist measurement and a hip measurement, to compute waist-to-hip ratio, alongside the standard height-and-weight BMI calculation, especially for patients whose BMI reads as normal. The press release does not publish the numeric cutoffs used to classify a waist circumference or waist-to-hip ratio as "high" or "low," so the underlying paper, not this summary, is what a clinician would need before applying any threshold.

How solid is it

This is a large, long-run observational analysis: more than 260,000 participants, an average 20-year follow-up, nine tracked outcomes, run by the multi-cohort Cross Cohort Collaboration and published in JACC, the American College of Cardiology's flagship journal. The journal's own editor-in-chief, Harlan Krumholz, publicly backed the conclusion as "enormously important." That said, the press release itself is thin on methodological detail: it does not name a funding source, does not break participants down by age, sex or country, and does not give accuracy figures for BMI alone, only the reclassification percentages and the 15% to 50% risk range. At the time of the release, the paper itself was available only as an embargoed copy on request to JACC's media office.

Risks and caveats

The study's own authors flag two limits: it has no data on physical activity, diet or genetic obesity risk, all established contributors to cardiovascular disease, and it measured each participant's waist circumference and waist-to-hip ratio only once, so it cannot say how changes in central fat over time affect risk. Separately, the release does not say any clinical body or guideline has adopted waist circumference or waist-to-hip ratio into routine practice. Krumholz's comment that they "should be part of routine cardiovascular risk assessment" is a recommendation, not a report that guidelines have already changed.

“It is time to abandon a sole focus on body mass index”

— Harlan M. Krumholz, Editor-in-Chief of JACC