Women with a bigger waist size relative to their hips have a greater heart attack risk than men with the same measurements, finds new research.
Decades of research has found strong links between being apple-shaped (due to the accumulation of belly fat) and a higher risk of both cardiovascular disease and type 2 diabetes, compared with being pear-shaped (heavier around the hips and thighs).
But a just-released study published in the Journal of the American Heart Association reveals that women are even more at risk from an apple-shaped physique than men are.
The researchers looked at heart disease risk in more than 500,000 women and men ages 40 to 69 whom they followed for seven years. They measured body mass index (BMI), waist circumference, and waist-to-hip ratio (waist circumference divided by hip circumference), among other things.
“The new finding of our study is that the extent to which waist-to-hip ratio is associated with risk of heart disease is greater in women than in men,” says Sanne Peters, Ph.D., research fellow in epidemiology at the George Institute for Global Health at the University of Oxford in the U.K. and lead author of the study.
“We found the risk increased consistently as the ratio increased,” he says. Even among those people with the lowest waist-to-hip ratio, every 0.09 increase—say, from 0.82 to 0.91—boosted the risk of heart attack in women by 50 percent. For men, the risk rose by 36 percent. In women, having a higher waist-to-hip ratio resulted in a 10 to 20 percent higher risk for heart disease than having a higher BMI.
However, the overall odds of having a heart attack in people ages 40 to 69 are still low. Just 1.8 to 4.2 percent of women and 3.3 to 11.3 percent of men in this age group have a heart attack, according to data from the National Health and Nutrition Examination Survey.
A waist-to-hip ratio greater than 0.85 in women and 0.9 in men is an indication of abdominal obesity, according to the World Health Organization. But given the results of this study, even if your waist-to-hip ratio is below those levels, you may be increasing your risk with every incremental gain in abdominal fat.
Calculate your waist-to-hip ratio: To calculate your own waist-to-hip ratio, measure your waist at its narrowest spot and divide it by the measurement of your hips at their widest spot.
The Trouble With Belly Fat
Belly fat, technically called visceral fat, is located deep in the abdominal cavity, where it surrounds organs such as the liver and pancreas. This means that the fat can trigger a variety of metabolic changes, including increased insulin resistance and higher triglyceride levels.
In contrast, the fat that settles around the hips and thighs—called subcutaneous fat—lies just under the skin and isn’t linked to such changes.
Women may be more vulnerable than men to storing fat in their abdomens due to hormonal and other age-related changes. A study published in the journal Obesity in 2015 found that during midlife, women gain an average of 4 percent of belly fat per year.
“It’s sneaky because the scale might not be changing, but fat can be redistributed even without any weight gain,” says Rasa Kazlauskaite, M.D., an endocrinologist at Rush University Medical Center in Chicago. And previous research suggests that genes associated with cholesterol and triglycerides and insulin resistance may be more affected by abdominal fat in women than in men.