Researchers analyzed data from more than 260,000 adults who were followed for an average of 20 years. The study examined the relationship between body-fat distribution and several cardiovascular outcomes, including heart attacks, strokes, heart failure, atrial fibrillation and cardiovascular-related deaths.
The findings showed that some people classified as having a normal or slightly overweight BMI still had a high waist circumference or waist-to-hip ratio. Among these individuals, the risk of most cardiovascular outcomes was approximately 15% to 50% higher than among people with lower waist measurements.
BMI measures a person's weight in relation to height, but it does not show where fat is stored in the body. Researchers say that abdominal or visceral fat, which accumulates around internal organs, may be particularly important because it is associated with inflammation, insulin resistance and damage to blood vessels.
The study, published in the Journal of the American College of Cardiology, suggests that relying solely on BMI could lead to some people being incorrectly classified as having a lower cardiovascular risk. Researchers therefore recommend considering waist circumference and waist-to-hip ratio alongside BMI when assessing heart health.
However, the researchers also noted limitations. Information on factors such as physical activity, diet and genetic risk was not fully available, while waist measurements were recorded only once. Therefore, the study demonstrates an association between abdominal fat and cardiovascular risk rather than proving that increased waist size directly causes heart attacks.
Experts say the findings highlight an important message: a normal body weight does not necessarily mean a person has a low risk of heart disease. Where fat is stored may matter as much as how much a person weighs.