A new study shows both obesity and a large belly appear to increase the risk of developing restless legs syndrome (RLS), a common sleep disorder characterized by an irresistible urge to move your legs. The research is published in the April 7, 2009, print issue of Neurology®, the medical journal of the American Academy of Neurology.

It is estimated that 5-10 percent of adults in the United States have RLS and the disorder often has a substantial impact on sleep, daily activities and quality of life.

For the study, researchers questioned 65,554 women and 23,119 men, all of whom were health professionals who took part in the Health Professionals Follow-Up Study or the Nurses’ Health Study II. None of the participants had diabetes, arthritis or were pregnant. Of the groups, 6.4 percent of the women and 4.1 percent of the men were identified as having RLS.

The research found men and women with a body mass index (BMI) score over 30 were nearly one-and-a-half times more likely to have RLS than people who were not obese.

In addition, people who were in the top 20 percent of the group for highest waist circumference were more than one-and-a-half times more likely to have RLS than the bottom 20 percent of the group with the lowest belly size. The results were the same regardless of age, smoking, use of antidepressants or anxiety.

“These results may be important since obesity is a modifiable risk factor that is becoming increasingly common in the U.S.,” said study author Xiang Gao, MD, PhD, with the Harvard School of Public Health in Boston. “More research is needed to confirm whether obesity causes RLS and whether keeping a low BMI score and small waist size could help prevent RLS.”

Gao says some studies suggest that obese people have lower dopamine receptor levels in the brain. “Since decreased dopamine function is believed to play a critical role in RLS as well, this could be the link between the two.” Dopamine is a chemical naturally produced by the body that transmits signals between nerve cells.

The study was supported by a grant from the National Institutes of Health and the National Institute of Neurological Disorders and Stroke.

The American Academy of Neurology, an association of more than 21,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as multiple sclerosis, restless legs syndrome, Alzheimer’s disease, narcolepsy, and stroke.

For more information about the American Academy of Neurology, visit http://www.aan.com.

Source: American Academy of Neurology (AAN)