May 2, 2011 -- A new study shows that people with coronary artery disease who carry extra fat around their waists appear to have an increased risk of dying compared to people who store their body fat elsewhere.
The study pooled and reanalyzed data on nearly 16,000 people with coronary artery disease from around the world. It found that those who were centrally obese, as measured by waist-to-hip ratio and waist circumference, had up to twice the risk of dying compared to those who didn’t pack fat around their midsections.
Researchers say the increased risk applies even to people who are otherwise normal weight, but have central obesity.
The study showed that the risk of death could be elevated even in people who don’t look very big.
“The waist might not be too large, but the distribution might still be abnormal,” says study researcher Francisco Lopez-Jimenez, MD, director of the cardiometabolic program at the Mayo Clinic in Rochester, Minn.
About 40% of the people in the study were considered normal weight, with a body mass index (BMI) under 25.
In these normal-weight patients, risks were elevated at waist sizes as small as 33 inches for men and 31 inches for women, if they also stored more fat around their midsections compared to their hips.
“A good chunk of the patients had a waist circumference that would be considered normal by all means, but the waist-to-hip ratio was abnormal,” says Lopez-Jimenez. “People tend to say if the BMI is fine, if the waist circumference is normal, then don’t worry about it. Well, if somebody is very skinny but the distribution of fat is abnormal they are at increased risk.”
“Abdominal fat is known to be more metabolically active than subcutaneous fat, the fat under the skin,” says Lopez-Jimenez.
Belly fat produces inflammatory chemicals and releases free-fatty acids into the blood. It also contributes to insulin resistance.
“That’s a fat that has been linked to high blood pressure, has been linked to diabetes, abnormal cholesterol, triglycerides,” Lopez-Jimenez says. “People with more visceral fat also tend to accumulate more fat in the liver.”
Thicker Waistlines and Heart Disease
Researchers sifted through the medical literature to find studies that focused on measures of central obesity -- waist circumference and waist-to-hip ratio -- and the risk of premature death in patients with heart disease.
Six studies, representing 15,923 patients from the U.S., France, Denmark, and Korea, were included in the final analysis.