Waist circumference and waist-to-hip ratio can identify cardiovascular risk that body mass index alone may miss, according to research announced by the American College of Cardiology on August 15, 2026. The study, published in the Journal of the American College of Cardiology, followed more than 260,000 people for an average of 20 years.
BMI divides weight in kilograms by height in metres squared and is widely used to classify normal weight, overweight and obesity. It does not show where body fat is located. That limitation matters because visceral fat around abdominal organs has been linked more strongly with heart disease and diabetes than subcutaneous fat directly beneath the skin. Waist measurements provide a simple indication of central fat distribution.
Researchers in the Cross Cohort Collaboration examined participants who had either waist-circumference or waist-to-hip-ratio data and information for at least one of nine outcomes. Those outcomes included fatal and non-fatal heart attack and stroke, heart failure, atrial fibrillation, total coronary heart disease, total cardiovascular disease, cardiovascular and coronary mortality, and death from any cause.
Among people 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 ratio. Conversely, 9 percent of people classified as having obesity had a low waist circumference, while 45 percent had a low waist-to-hip ratio.
Participants with a normal or overweight BMI but high waist measures had a 15 to 50 percent greater risk for most of the studied outcomes. People with obesity and a low waist circumference did not have significantly different risks from normal-weight participants with a low waist circumference for most outcomes. All-cause mortality was the exception, with significantly lower risk reported in the obesity-and-low-waist group.
The results are associations from cohort data and do not show that changing a waist measurement by itself causes risk to rise or fall. The study also lacked information on physical activity, diet and genetic obesity risk. Waist measurements were taken only once, limiting analysis of how changes in abdominal fat over time related to later outcomes.
The authors argue that clinicians should consider central adiposity throughout the BMI spectrum during primary-prevention assessment. Someone can fall within a conventional normal BMI range while carrying abdominal fat associated with higher risk, and another person’s obesity-range BMI may not convey the same risk profile when waist measures are low.
The findings do not make waist circumference or waist-to-hip ratio a diagnosis, nor do they replace a broader clinical evaluation. They indicate that adding two accessible measurements can refine population-level risk classification beyond weight and height alone. Individual medical decisions should still account for the full health history and other established cardiovascular factors.
