FRIDAY, Aug. 8 (HealthDay News) -- A protein produced by fat cells may play a pivotal role in increasing an older American's risk for a heart attack even if they are losing weight, a new report says.

Levels of adiponectin increase in the bloodstream when people lose weight and appear to endanger the cardiovascular health of older people, according to the new study to be published in The Journal of Clinical Endocrinology & Metabolism.

This finding, though, appears odd, because past studies have shown high adiponectin concentration is associated with lower risks of diabetes and cholesterol abnormalities.

"This study is significant because previous findings have been contradictory, and the present investigation includes the largest number of heart attacks in an elderly group to date," Dr. Jorge Kizer, an associate professor of medicine and public health at Weill Cornell Medical College in New York City, said in a news release issued by the journal's publisher. "Our findings make a persuasive case that adiponectin is in fact associated with an increase in heart disease risk in older persons."

The new study looked at a sample of 1,386 adults, aged 65 to 100, from around the country. Of these, 604 had heart disease, with those with the highest adiponectin levels being most likely to suffer a heart attack.

The researchers theorized that higher adiponectin levels may indicate underlying disease, or even have direct harmful effects especially in the elderly. Previous studies show adiponectin increases energy expenditure in the central nervous system of mice -- something that could be significantly harmful if also occurring in older adults by accelerating the loss of skeletal muscle.

The findings are consistent, though, with other recent studies tying high adiponectin to mortality in the elderly.

"This study shows that this abundant product of fat cells is a marker and perhaps even a mediator of worsened outcomes in persons aged 65 years and older," Kizer said.

More information

The National Institute of Health has more about healthy aging.