Men with restless legs syndrome (RLS) were more likely to die during an eight-year study than those without the condition, even after their age and other health problems were taken into account, researchers found.
The condition, which remains controversial, causes unpleasant sensations in the legs when a person is at rest, triggering an uncontrollable urge to move the legs to get relief.
Its exact cause is unknown, but RLS has been linked to heart problems and to early deaths among people with kidney disease (see Reuters Health story of Sept 16, 2011 here: reut.rs/pQJZ41).
Prior studies have come to mixed conclusions on whether RLS plays a role in early deaths in general - and some researchers have accused drug companies and the media of "disease mongering" to make RLS seem worse than it is.
"There was a lot of debate about whether RLS was a real disease several years ago. More and more people think RLS is a real disease," said Dr. Xiang Gao, who worked on the new study at Brigham and Women's Hospital and Harvard Medical School in Boston.
But, he added, "We still know very little about its clinical consequences."
His team's data come from a large study of US health professionals launched in the mid-1980s. In 2002, 18,425 of those men were asked about symptoms of RLS - and 690 said they had uncomfortable leg sensations at least five times per month.
Gao and his colleagues tracked study participants until 2010, when 15,660 were still alive. After taking in account men's age, weight, chronic diseases and lifestyle, they found those who'd reported having RLS were 30 percent more likely to die during the study period.
For those without any chronic conditions such as cancer or high blood pressure - the "relatively healthy group," according to the authors - RLS was tied to a 92 percent higher chance of dying early, they reported Wednesday in Neurology.
Gao speculated that poor sleep quality, worsening heart health and obesity could all factor into the link between restless legs and earlier death.
"All of them could be potential mechanisms, but we still don't know which one," he told Reuters Health. "Maybe they work together."
"It could be the pain (of RLS) or it could be the sleep loss that causes the problem," said Dr. Brian Murray, a sleep researcher at Sunnybrook Research Institute and the University of Toronto, who wasn't involved in the new study.
"Or it could be there's an underlying problem like renal failure or iron deficiency that's associated with restless legs."
The new study doesn't prove that restless legs syndrome, itself, puts men at higher risk of dying. And researchers don't know if potentially different causes of RLS affect long-term risks differently - or whether the link also applies to women.
"I think we're making some significant progress in gaining understanding, but we don't have the full story yet," Murray told Reuters Health.
RLS can be treated with medications, including pramipexole (marketed as Mirapex) and ropinirole (Requip), both drugs for Parkinson's disease. Symptoms may also go away with lifestyle changes, such as relaxation, exercise, getting enough iron and avoiding caffeine.
"We don't know yet, will treatment of the restless legs help reduce mortality?" Murray said. "We know there's an association with a problem, but we don't know if treating it will reduce that risk."
SOURCE: bit.ly/lUcacJ Neurology, online June 12, 2013.