Washington, Jan 1 (IANS) Erectile dysfunction (ED) is more common among older men with restless leg syndrome (RLS) than in those without it.

Results show that ED was 16 percent more likely in men with RLS symptoms that occur five to 14 times per month and 78 percent more likely in men whose RLS symptoms occur 15 or more times a month.

The associations were independent of age, body mass index, use of anti-depressants, anxiety and other possible risk factors for RLS.

The results suggest it is likely that the two disorders share common mechanisms, said Xiang Gao, research scientist at the Harvard School of Public Health.

'The mechanisms underlying the association between RLS and erectile dysfunction could be caused by hypofunctioning (less than optimum functioning) of dopamine in the central nervous system, which is associated with both conditions,' said Gao.

Dopamine is believed to release chemicals (endorphins) that allow us to feel pleasure.

Fifty-three percent of RLS patients and 40 percent of participants without RLS reported having erectile dysfunction, defined as a poor or very poor ability to have and maintain an erection sufficient for intercourse.

Data were collected from 23,119 men who participated in the Health Professionals Follow-up study, a large ongoing US cohort of male dentists, optometrists, osteopaths, podiatrists, pharmacists and veterinarians, said a Harvard release.

Participants were aged between 56 and 91 years, with a mean age of 69 years. To reduce possible misclassification of RLS, participants with diabetes and arthritis were excluded.

About four percent of participants had RLS (944 of 23,119 men), and about 41 percent (9,433 men) had erectile dysfunction. Men with RLS were older and were more likely to be Caucasian. The prevalence of erectile dysfunction also increased with age.

The study was published in the Friday issue of Sleep.