If you’re one of those people who tends to put on weight around your middle, what doctors call an “apple shape” — what the rest of us call a beer belly — you’ve probably been told that you’re at higher risk of heart disease. But large new review study suggests you shouldn’t be too discouraged after all.
It turns out that the apple-shaped among us are not at any higher risk of heart trouble as people with pear shapes or any other kind of fat distribution. In the latest study, researchers at the Emerging Risk Factors Collaboration in the U.K. reviewed records of more than 220,000 participants in 58 different trials that followed volunteers for more than 10 years for heart-related events. They found that body shape, or fat distribution, did not seem to affect heart disease risk.
In fact, the researchers write in the journal Lancet, various measures of obesity, including body mass index (or BMI, a combined measure of height and weight), waist circumference and waist-to-hip ratio, all had about the same predictive value in identifying increased risk of a heart attack. What’s more, compared to the forecasting power of known risk factors such as high cholesterol, high blood pressure and a history of diabetes, the obesity measures added very little to the accuracy of risk assessment.
Previous studies had focused not just on overweight, but on the type and location of fat deposits as a red flag for heart disease. The thinking was that even without blood tests for cholesterol or blood pressure, body shape alone could alert doctors and patients to patients might be at higher risk of heart problems. One headline-grabbing survey reported a three-fold increased risk in heart disease among those with abdominal fat — folks with apple-shaped bodies — and speculated that visceral fat, which tends to accumulate around the middle, is particularly hazardous for the heart, since it nestles deep within organs and can pump out hormones that alter insulin sensitivity and promote diabetes.
But the new findings from the U.K. suggest otherwise, reporting that fat, while an important factor contributing to heart disease, may not play as dominant a role as other risk factors such as cholesterol, blood pressure and diabetes, and shouldn’t substitute for these measures if they are available.
That doesn’t mean that losing weight isn’t important for avoiding heart disease, however. As the authors write:
The main finding of this study does not, of course, diminish the importance of adiposity as a major modifiable determinant of cardiovascular disease. Rather, because excess adiposity is a major determinant of the intermediate risk factors [of blood pressure, history of diabetes, and cholesterol], our findings underscore the importance of controlling adiposity to help prevent cardiovascular disease.
The results also seem to add more data to the ongoing debate over whether BMI or waist circumference is a better way to assess what’s going on inside the body when it comes to heart disease. Some have argued that BMI is too blunt a measure of appropriate weight, since it can’t distinguish between muscle and fat mass, and that waist circumference is a better way to pick up on increasing weight gain in the form of fat. But the current study seems to refute that hypothesis, finding that waist measures don’t appear to add much to the ability to predict future heart disease or stroke.
To make sense of the conflicting data, Rachel Huxley, an epidemiologist at the University of Minnesota and David Jacobs of the University of Sydney write in an accompanying editorial:
BMI continues to be useful as an indicator of adiposity, despite its obvious and occasional misrepresentation of muscular people and lack of sensitivity to body shape and composition. … But identification of which overweight individuals without risk factors for cardiovascular disease will do on to develop those risk factors, and ultimately clinical cardiovascular disease, remains a challenge — here, blood tests continue to be helpful.
Looks, after all, aren’t everything, and that seems especially true when it comes to the role that body shape plays in heart disease.