June 28, 2012

Risk Factors for Rare Sleep Disorder Possibly Identified

(Ivanhoe Newswire) — It´s hard enough sleeping with someone who tosses and turns at night, but imagine if they kicked and punched instead! Thankfully, researchers may have possibly identified risk factors associated with this rare sleep disorder.

This disorder, called REM sleep behavior disorder, is characterized by people who do not have the normal lack of muscle tone that occurs during rapid eye movement (REM) sleep. This causes them to act out their dreams in a physical way. Sometimes their movements can be violent, causing injury to the person or their bed partner. The disorder occurs in around 0.5% of adults.

"Until now, we didn't know much about the risk factors for this disorder, except that it was more common in men and in older people," study author Ronald B. Postuma, MD, MSc, with the Research Institute of the McGill University Health Centre (MUHC) in Montreal and a member of the American Academy of Neurology, was quoted as saying. "Because it is a rare disorder, it was difficult to gather information about enough patients for a full study. For this study, we worked with 13 institutions in 10 countries to get a full picture of the disorder."

The disorder can also be a precursor to neurodegenerative diseases like Parkinson´s disease and Lewy body dementia. Past studies have shown that more than 50% of people with REM sleep behavior disorder go on to develop a neurodegenerative disorder years or even decades later.

"Due to this connection, we wanted to investigate whether the risk factors for REM sleep behavior disorder were similar to those for Parkinson's disease or dementia," Postuma was quoted as saying.

The study analyzed 347 people with REM sleep behavior disorder who were compared to 347 people who did not have the disorder. Of those, 218 had other sleep disorders and 129 had no sleep disorders.

The study results were mixed. While smoking was found to be a protective factor for Parkinson's disease, they found that people who smoked were more likely to develop REM sleep behavior disorder. On the other hand, pesticide use is a risk factor for both disorders. Studies have shown that people who drink coffee are less likely to develop Parkinson's, but this study found no relationship between coffee drinking and REM sleep behavior disorder.

Participants with REM sleep behavior disorder were 43% more likely to be smokers, with 64% of those with the disorder having ever smoked, compared to 56% of those without the disorder. They were 59% more likely to have had a previous head injury with loss of consciousness, 67% more likely to have worked as farmers, and more than twice as likely to have been exposed to pesticides through work. Those with the disorder also had fewer years of education, with an average of 11.1 years, compared to 12.7 years for those without the disorder.

Source: Neurology, June 2012