Researchers followed about 360,000 Europeans enrolled in one of the largest, longest health studies in the world.
They found that people with the most belly fat had about double the risk of dying prematurely as people with the least amount of belly fat.
Death risk increased with waist circumference, whether the participants were overweight or not.
The study provides some of the strongest evidence yet linking belly fat to early death, says lead author Tobias Pischon, MD, MPH. It appears in the Nov. 12 issue of TheNew EnglandJournal of Medicine.
"Our study shows that accumulating excess fat around your middle can put your health at risk even if your weight is normal," he says. "There aren't many simple individual characteristics that can increase a person's risk of premature death to this extent, independent of smoking and drinking."
Belly Fat Research
It has long been recognized that people who carry their excess weight around their middles -- those who are apple-shaped instead of pear-shaped -- have a higher risk for heart attacks and strokes.
Recent research also suggests a link between belly fat and a range of other diseases, including diabetes, some cancers, and even age-related dementias.
But it has not been clear whether the increase in death risk associated with abdominal obesity occurs independently of recognized risk factors like general obesity, Pischon says.
The researchers used two measures of abdominal obesity -- waist circumference and waist-to-hip ratio -- in their attempt to better understand the role of belly fat in early death.
During the follow-up period, 14,723 of the study participants died.
After adjusting for overweight and obesity, as measured by body mass index (BMI), waist circumference and waist-to-hip measurements were both independently associated with an increased risk for early death.
- Men and women with the largest waists (more than 40 inches for men and 35 inches for women) had roughly double the risk of premature death as men and women with the smallest waists (less than 34 inches for men and 28 for women).
- Each 2-inch increase in waist circumference was associated with close to a 17% increase in mortality in men and a 13% increase in women.
- Waist-to-hip ratio also strongly predicted mortality.
"The most important result of our study is the finding that not just being overweight, but also the distribution of body fat, affects the risk of premature death," Pischon says.
The findings come as no surprise to University of Michigan cardiologist and research scientist Daniel Eitzman, MD.
Work by Eitzman and colleagues in mice found that belly fat -- also known as visceral fat -- produces more inflammation than fat found in other areas of the body.
Inflammation is thought to play a key role in heart disease and a host of other chronic diseases.
Eitzman tells WebMD that measurement of waist circumference or waist-to-hip ratio are important for assessing the risk of inflammation-driven disease.
"Studies like this focus attention on the importance of measuring visceral fat, which is not now routinely done in clinical practice," he says.
Are You an Apple or a Pear?
So how do you tell if you have more belly fat than is healthy?
- To measure your waist circumference, place a tape measure around your waist at the smallest point, which is usually just above the navel. A waist size of 40 inches in men and 35 inches in women is generally considered to indicate increased health risk.
- Waist-to-hip ratio is calculated by measuring your waist at the smallest point and your hips at the widest point -- usually at the widest part of the buttocks -- and dividing the waist measurement by the hip measurement. A waist-to-hip ratio of greater than 0.9 for men and 0.8 for women is generally considered high risk.