Abdominal flab increases artery damage: can be reversed by weight loss

American Heart Association
Tuesday, 15 January 2002

Weight gain, particularly in the abdominal area, appears to raise the amount of inflammatory substances that can contribute to artery clogging, increasing the risk for heart disease, according to a study in today's rapid access publication of Circulation: Journal of the American Heart Association. Rapid access Circulation is published online before it is printed.

"Atherosclerosis is now recognized as a disorder characterized by a chronic inflammation," says the study's lead author Dario Giugliano, M.D., professor of metabolic disease of the department of geriatrics and metabolic diseases, Policlinico della Seconda Universita di Napoli, Italy

"We know that key markers of inflammation called cytokines predict risk for heart attacks and strokes. We also know that cytokines are produced and stored in abdominal fat. Thus women who are obese may be at higher risk for blood clotting problems associated with elevated cytokines," he says.

This is the first study to prospectively investigate the effect of weight loss on circulating levels of cytokines in obese women without heart disease and with different degree of abdominal fat, he says.

"The good news is the inflammation can be corrected by drugs or lifestyle modifications. Weight loss may be another safe method for reducing the inflammatory status of obese individuals to reduce their cardiovascular risk," says Giugliano.

The study, which included 56 healthy premenopausal obese women and 40 women of similar age, but normal weight, examined the relationship between obesity and cytokines. Researchers wanted to find out if there was an association between the amount of fat tissue a person had and the amount of circulating cytokines. Researchers also tested endothelial function, which is a measure of how well the blood vessels function. The endothelium is the inner lining of the blood vessels that can become damaged from fatty deposits.

Women in the study completed a personal and medical history questionnaire. All women were weighed. Obesity was measured by two methods: body mass index (BMI), which is a ratio of weight and height, and waist-hip ratio (WHR) calculated as waist circumference in centimeters divided by hip circumference in centimeters.

Women were treated with a multidisciplinary approach consisting of diet and exercise, counseling and liposuction for those who were candidates and agreed to the procedure. The average daily caloric intake was 1,300 calories. In addition to standard tests for blood cholesterol, levels of the following circulating cytokines were measured: TNF-alpha; IL-6, P- selectin, ICAM-1 and VCAM-1. At the beginning of the study, the levels were significantly higher in the obese group than the nonobese group and were related to BMI and WHR.

After 12 months, most of the obese women lost at least 10 percent of their initial body weight, with an average decrease of 10 kilograms (22 pounds). All women increased their physical activity from 46 minutes to 131 minutes per week. Compared with baseline values, sustained weight loss was associated with reductions of BMI, WHR, fasting glucose and insulin levels.

It was also associated with reductions in cytokines. TNF went from 5.8 picograms/milliliter (pg/mL) to 4 pg/mL; IL-6 dropped from 3.1 pg/ml to 1.7 pg/mL and p-selectin declined from 87.5 nanograms/milliliter (ng/mL) to 61.5. ng/mL. ICAM-1 dropped from 315 ng/mL to 234 ng/mL. VCAM-1 went from 708 ng/mL to 590 ng/mL. These levels of cytokines following weight loss were similar to levels in the nonobese individuals.

Researchers also found that the endothelial function was improved following weight loss.

"Our results support a role for fat as a factor for atherosclerotic disease, possibly through inappropriate cytokine secretion. It is reassuring that diet, exercise, and lifestyle changes can so effectively reduce rates of both artery clogging and diabetes. Interestingly, high cytokine responders are candidate for both conditions, and weight loss, particularly the loss of fat, can reduce the cytokine response."

For more information, or to contact American Heart Association, see their website at: www.americanheart.org