For women, their waist size and waist-to-hip ratio may have an impact on heart attack risk, according to a new study.
But as a measurement, BMI says nothing about body fat distribution and does not differentiate between fat types — such as visceral fat versus subcutaneous fat.
Visceral fat is so named because it builds around one's internal organs, such as the pancreas, liver, and intestines. This type of fat is more closely linked with insulin resistance and other cardiometabolic risk factors.
Sex may influence the type of fat that a person is more predisposed to. Studies have revealed, for instance, that men are more likely to accumulate visceral fat, whereas women tend to have more subcutaneous fat.
Now, a new study zooms in on body fat distribution and the risk of heart attack. Researchers led by Sanne Peters — of the George Institute for Global Health at the University of Oxford in the United Kingdom — studied the body size and shape of almost half a million adults to locate the best predictors of heart attack risk.
Waist-to-hip ratio dangerous for women
Using the U.K. Biobank database, Peters and colleagues examined almost 500,000 people aged between 40 and 69, who were followed up for a period of 7 years.
During this time, 5,710 cases of heart attack were recorded — 28 percent of which occurred in women.
The team applied Cox regression models to calculate the risk of myocardial infarction associated with BMI, as well as "waist circumference, waist-to-hip ratio, and waist-to-height ratio."
The study yielded some interesting results regarding sex differences in heart attack risk. The study authors summarize their findings.
"Although general and central adiposity measures each have profound deleterious effects on the risk of [heart attack] in both sexes, a higher waist circumference and waist-to-hip ratio conferred a greater excess risk of [heart attack] in women than in men."
"Waist-to-hip ratio was more strongly associated with the risk of [heart attack] than body mass index in both sexes, especially in women," they continue.
"Our findings support the notion that having proportionally more fat around the abdomen (a characteristic of the apple shape) appears to be more hazardous than more visceral fat which is generally stored around the hips (i.e., the pear shape)."
However, this is not the first study to draw attention to body fat distribution as being particularly detrimental to women's cardiometabolic health. Previous research that Medical News Today reported on found that, while both men and women had visceral fat, this entailed a higher cardiometabolic risk for women.
According to the most recent statistics from the Centers for Disease Control and Prevention (CDC), over 36 percent of adults in the United State are obese, with women being more affected than men.
As the CDC note, over 38 percent of U.S. women are obese, while slightly over 34 percent of men have the condition.