WASHINGTON—A person’s waistline may reveal cardiovascular danger that body mass index (BMI) misses, according to a large study published in the Journal of the American College of Cardiology. The analysis, involving more than 260,000 people followed for an average of two decades, found that waist circumference (WC) and waist-to-hip ratio (WHR) could substantially reclassify heart and vascular risk across the full range of BMI categories. The findings challenge the long-standing practice of using BMI as the primary measure of overweight, obesity and future cardiovascular disease.
BMI is calculated by dividing body weight in kilograms by height in meters squared. Although simple and inexpensive, the measure cannot show where fat is stored or distinguish fat from muscle. That limitation is important because abdominal fat, particularly visceral adipose tissue surrounding internal organs, is metabolically active and has been linked to insulin resistance, inflammation, high blood pressure and abnormal blood lipid levels. Subcutaneous fat beneath the skin appears to have weaker associations with cardiovascular disease, meaning that two people with identical BMIs may have very different biological risk profiles.
Researchers from the Cross Cohort Collaboration examined whether adding measurements of abdominal fat distribution to BMI could improve predictions of major cardiovascular outcomes. Participants had available WC or WHR data and were assessed for one or more of nine outcomes: fatal or nonfatal myocardial infarction, fatal or nonfatal stroke, heart failure, atrial fibrillation, total coronary heart disease, total cardiovascular disease, coronary heart disease mortality, cardiovascular disease mortality and all-cause mortality. The long follow-up allowed the investigators to evaluate whether body-fat distribution was associated with events that developed years after the initial measurements.
The study showed that central adiposity was present in a meaningful proportion of people whose BMI would traditionally place them in a lower-risk category. Among participants classified as normal weight by BMI, 5 percent had a high waist circumference and 18 percent had a high waist-to-hip ratio. In the overweight group, 39 percent had a high waist circumference and 40 percent had a high waist-to-hip ratio. These results suggest that a substantial number of people may carry elevated abdominal fat without being identified as at risk by BMI alone.
The implications were especially striking among people with normal weight or overweight. Those with a clinically high WC or WHR had a 15 to 50 percent greater risk for most of the nine outcomes compared with participants whose BMI and central-adiposity measures were in lower-risk ranges. The association persisted across several forms of cardiovascular disease, indicating that abdominal fat distribution may provide information beyond the broad weight categories used in routine medical practice.
The findings also complicated the assumption that obesity automatically identifies the people at greatest cardiovascular risk. Among participants with obesity, 9 percent had a low waist circumference and 45 percent had a low waist-to-hip ratio. Individuals with obesity but low WC were not significantly different in risk from normal-weight participants with low WC for most outcomes. The exception was all-cause mortality, for which the obesity group with low WC showed a significantly lower risk. Because the study was observational, however, these results do not establish that a smaller waist protects against disease or explain why different patterns appeared across BMI categories.
“Where fat is distributed matters,” said Michael J. Blaha, MD, MPH, senior author and director of clinical research at the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease. He noted that waist circumference and waist-to-hip ratio appeared to reclassify risk defined by traditional BMI thresholds, including among people considered to have normal weight. Lead author Zeina A. Dardari, PhD, MS, said clinicians should consider central adiposity across the entire BMI spectrum when assessing cardiovascular risk in primary prevention.
Waist circumference is a direct measurement around the abdomen, while WHR compares waist size with hip size. Both are indirect markers of body-fat distribution and can be influenced by sex, age, ethnicity, body shape and measurement technique. Neither test can determine precisely how much visceral fat a person has; imaging methods such as computed tomography or magnetic resonance imaging are more specific but are expensive and impractical for routine screening. Nevertheless, the researchers argue that these simple anthropometric measurements can add clinically relevant information at low cost.
The study has important limitations. Researchers lacked detailed data on physical activity, diet and genetic susceptibility to obesity, all of which can influence cardiovascular disease. WC and WHR were measured only once, so the analysis could not determine how changes in abdominal fat over time affected risk. The findings also describe associations rather than direct cause-and-effect relationships. Even so, the scale and duration of the study support the view that BMI should be treated as one component of cardiovascular assessment rather than a complete measure of health risk. Adding waist-based measurements could help identify people whose apparent weight category conceals a more concerning pattern of fat accumulation.
Subject of Research: The relationship between body mass index, waist circumference, waist-to-hip ratio and long-term cardiovascular disease risk.
Article Title: Risk Reclassification Beyond BMI by Waist Circumference and Waist-to-Hip Ratio Across Nine Cardiovascular Outcomes: Results from the Cross-Cohort Collaboration
News Publication Date: 11-Aug-2026
Web References: Journal of the American College of Cardiology, DOI: 10.1016/j.jacc.2026.05.050
References: Dardari ZA et al., “Risk Reclassification Beyond BMI by Waist Circumference and Waist-to-Hip Ratio Across Nine Cardiovascular Outcomes: Results from the Cross-Cohort Collaboration,” Journal of the American College of Cardiology.
Keywords: cardiovascular disease, heart disease, body mass index, BMI, waist circumference, waist-to-hip ratio, central adiposity, visceral fat, obesity, cardiovascular risk, myocardial infarction, stroke, heart failure, atrial fibrillation
Tags: Abdominal fat and heart disease risk predictionComparing subcutaneous and visceral fat impactsEnhancing cardiovascular risk prediction modelsImpact of fat distribution on heart diseaseLarge-scale study on obesity measures and heart riskLimitations of BMI for assessing obesity-related health risksLimitations of BMI in obesity assessmentLong-term followRole of abdominal fat in inflammation and insulin resistancevisceral adipose tissue and metabolic healthWaist circumference and cardiovascular healthWaist-to-hip ratio as a cardiovascular risk indicator
