Older women who carry more body fat around their waist than on their legs may be at an increased risk of a heart attack and stroke — even if they are not overweight, according to new research published in the European Heart Journal.
This is not the first study to find that that “apple-shaped” women (those who store fat predominantly around their abdomen) tend to have a higher risk of cardiovascular disease than “pear-shaped” women (those who store fat predominantly on their hips and thighs).
But those earlier studies mostly focused on women who were overweight or obese. In the current study, all the women had what most experts consider a healthy body mass index (BMI) of between 18.5 and 25.9.
“Our findings suggest that postmenopausal women, despite having normal weight, could have varying risk of cardiovascular disease because of different fat distributions around either their middle or their legs,” said Qibin Qi, the study’s lead author and an associate professor at the Albert Einstein College of Medicine, in a released statement.
“In addition to overall body weight control, people may also need to pay attention to their regional body fat, even those who have a healthy body weight and normal BMI,” he added.
Gathering the data
For the study, Qi and his colleagues used data collected from 2,683 American women who had been recruited into a larger, ongoing research project known as the Women’s Health Initiative (WHI) in the 1990s, when they were between the ages of 50 and 79. The researchers selected that subset of women from the WHI because they all had a “normal” BMI and no signs of cardiovascular disease when the study began. Each had also undergone DEXA scans to measure the body fat on their abdomen and legs measured.
The women were followed for an average of 18 years, through February 2017. During that period, 291 of them were diagnosed with — or died from — some form of cardiovascular disease, including stroke and heart attack.
Qi and his colleagues divided the women into four quartiles based on the percentage of body fat they carried around their abdomens and on their legs. They then calculated how the risk of developing cardiovascular disease compared between women in the highest and lowest quartiles for each area of body fat.
Those calculations were done after the researchers adjusted the data for other factors that can influence the risk of cardiovascular disease, such as age, racial and ethnic background, smoking and alcohol consumption, physical activity level, family history of heart attack and stroke, and use of statins, aspirin, hormone therapy (for menopause) and other drugs.
After crunching all that data, the researchers found the following:
- Women with the highest percentage of fat stored around their abdomen were twice (91 percent) more likely to have developed cardiovascular disease than women with the lowest percentage of abdominal fat.
- Women with the highest percentage of fat stored on their legs were 38 percent less likely to have developed cardiovascular disease than women with the lowest percentage of fat stored on their legs.
- The cardiovascular-disease risk was greatest, however, for women with the lowest percentage of leg fat and the highest percentage of abdominal fat. Their risk of developing cardiovascular disease was more than three times higher than that of women with the highest leg fat and the lowest abdominal fat.
Based on their findings, Qi and his colleagues estimate that if 1,000 women in the study had reduced their abdominal fat from 37 percent to 27 percent but kept their leg fat the same, six fewer cases of cardiovascular disease would have occurred during each year of the study.
They also estimate that if 1,000 women in the study had kept their abdominal fat the same but increased their leg fat from less than 42 percent to more than 49 percent, three fewer cases of cardiovascular disease would have been avoided each year.
The study is observational, so it can’t prove that the location of body fat on the women was responsible for the differences in their risk of developing cardiovascular disease. Other factors — ones not adjusted for in the analysis — might also explain the results.
For example, the women in the study with more abdominal fat and less leg fat had higher rates of type 2 diabetes, a medical condition linked with cardiovascular disease. That condition was not adjusted for in the study.
In addition, the study included only women aged 50 or older, and most of them were white. The findings may not be applicable, therefore, to younger women or to women of other racial groups. Nor is it known if the findings are applicable to men.
Lowering the risk
Although this study reveals an interesting link between where body fat is stored and the risk of cardiovascular disease, it doesn’t explain why that link occurs.
Other research may offer some possible explanations, however, as Qi and his co-authors point out in their paper. Scientists have found that when fat is stored in large amounts around the organs in the abdomen, various metabolic problems, including inflammation of the blood vessels, can develop, raising the risk of cardiovascular disease. Researchers have also found that leg fat appears to be linked to a decreased risk of those metabolic problems, although the reason for that association is unclear.
Nor is it clear how women can apply the current study’s findings to their lives.
“Unfortunately, we don’t know how to relocate fat from the belly to the legs. This is influenced by genetics,” Qi told New York Times reporter Nicholas Bakalar.
“Exercise will help with weight loss,” he added, “but we don’t know what kind of exercise would relocate body fat.”
The best protection against cardiovascular disease for women (and men), therefore, continues to be a healthy lifestyle: eat a healthful diet, get plenty of regular exercise, limit (or eliminate) your alcohol consumption, don’t smoke, manage stress and get enough sleep.
And maintain an overall healthy weight.
FMI: The study, which was funded by the National Institute of Health, can be read in full on the European Heart Journal’s website.