Caucasian women may suffer from restless legs syndrome (RLS), a sleep disorder characterized by the strong urge to move the legs, up to four times more than African-American women, a new study has found.

The study, presented at CHEST 2009, the 75th annual international scientific assembly of the American College of Chest Physicians (ACCP), found that, overall, non-African-American (NAA) patients experienced RLS four times more often than African-Americans (AA). Furthermore, 2 out of 5 Caucasian women were found to have RLS, nearly four times the incidence of RLS in African-American women and the highest incidence among all groups.

"There are significant ethnic differences in the prevalence of restless legs syndrome, but the exact causes of higher prevalence among Caucasians are unknown," said Ammar Alkhazna, MD, University of Missouri, Kansas City, MO. "This likely reflects a combination of factors, including a genetic predisposition to RLS, diet—including iron intake—medications, and possibly culture."

To determine the incidence of RLS among AA and NAA patients, Dr. Alkhanza and his colleagues analyzed standardized interview responses from 190 patients seen at a primary clinic. Of the patients, 103 were AA (42 percent were men) and 87 were NAA, of which 40 percent were men and the majority were Caucasians. Among AA, the diagnosis of RLS was definite in 12 percent of patients, while among NAA, the diagnosis of RLS was definite in 36 percent. In the AA group, the prevalence of RLS was 12 percent for both genders. In the NAA group, the prevalence of RLS among men was 29 percent and 40 percent among women.