Not all fat is equal -- where it sits on the body matters to your health. Higher "trunk fat" in women was associated with an increased incidence of atherosclerosis or hardening of the arteries, while more leg fat predicted lower risk of this type of coronary artery disease, a new study published Monday in the European Heart Journal finds.
Not only is the proverbial pear shaped woman heart healthier than her apple shaped friend, but she may even be at lower risk of cardiovascular disease than slim-waisted women who lack "thunder thighs," the new research suggests.
For the new study, researchers followed more than 2,500 women between the ages 50 and 79 for an average of 18 years. All these postmenopausal women fell within the normal range of Body Mass Index. The researchers measured waist and thigh fat for all the women and categorized them into quarters highest to lowest for each measurement. An individual woman, for example, might fall in the highest quarter for waist fat and second lowest quarter for thigh fat.
During nearly two decades of follow-up, 202 of the women experienced a heart attack or other coronary heart disease incident, while 105 women suffered strokes; 16 women experienced both a stroke and some episode of coronary heart disease.
Analyzing the data, the Albert Einstein College of Medicine researchers found that whole-body fat was not linked to risk of cardiovascular disease, though trunk fat was. Women who had "both high trunk fat and low leg fat had a more than three-fold increased risk" of cardiovascular disease compared with women with low trunk fat and high leg fat, the study authors noted. These relationships between fat and heart disease risk held up even when they factored other known risks, such as smoking, into their analysis.
"Our results showed that relatively higher trunk fat levels were associated with various metabolic disturbances" including elevated insulin levels, systemic inflammation, and abnormal cholesterol levels, concluded the study authors. Meanwhile, the relationship between leg fat and these same unhealthy signs "were generally in the opposite directions," they stated.
In an editorial published alongside the new study, Dr. Matthias Blüher and Dr. Ulrich Laufs, both of University of Leipzig in Germany, note that previous studies have shown that lower body weight along with higher body weight are linked to an increased risk of developing atherosclerosis.
The strongest predictor of cardiovascular disease and early death due to heart disease has been increased abdominal or trunk fat -- and not high BMI, they noted. "Not everybody with obesity develops premature atherosclerosis and there is substantial variation in cardiovascular risk even in individuals with normal BMI," wrote Blüher and Laufs, neither involved in the new research.
Importantly, the new study suggests that leg fat may have a positive effect on atherosclerosis risk, they wrote, adding that this needs to be studied in-depth. "Compared with visceral depots, leg fat may release lower concentrations of potentially harmful metabolites," they theorized. They also believe leg fat may reduce heart disease risk due to "anti-inflammatory factors."
Heart disease, which includes atherosclerosis, heart attack and related conditions, is the leading cause of death for women in the United States, responsible for about 1 in every 5 female deaths, according to the US Centers for Disease Control and Prevention.
The authors of the new study conclude that their findings "highlight the importance of fat distribution beyond overall fat mass in the development of cardiovascular disease." The healthiest hearts may belong to those women who stretch the thighs of their jeans.