March 24, 2023 -- Restless legs syndrome may be a risk factor for dementia or a very early warning sign of dementia in older adults, new research hints.
RLS is a condition that causes an uncontrollable urge to move the legs, typically in the evening or nighttime hours when sitting or lying down.
In a large study of older adults, those who had RLS were significantly more likely to develop dementia over more than a decade than peers without RLS.
RLS is associated with poor sleep, depression, anxiety, poor diet, and obesity -- all known risk factors for dementia. But ties between RLS and dementia are unclear.
To investigate, researchers from Korea studied about 2,500 adults with RLS and a control group of more than 9,900 matched people without RLS. All were 73 years old on average.
Over the course of about 10 years, a total of 874 of them developed dementia, and those with RLS were significantly more likely to develop dementia (10% versus 6%).
After accounting for factors that might influence the risk of dementia, adults with RLS were 46% more likely to develop dementia than adults without RLS. The study was published earlier this month in the peer-reviewed journal Alzheimer's Research and Therapy.
RLS may precede a decline in thinking and memory leading to dementia and could be viewed as a “newly identified” risk factor or very early sign of dementia, said Eosu Kim, MD, PhD, with Yonsei University College of Medicine in Seoul, and colleagues.
If confirmed in future studies, the researchers say regular checkups for cognitive decline in older people who have RLS may aid in early detection and intervention for those at risk for dementia.
“There is now an increasing literature that shows sleep as a modifiable risk factor for cognitive decline,” said Thanh Dang-Vu, MD, PhD, with Concordia University in Montreal, Canada, who wasn’t involved in the study.
He noted that prior studies have suggested that both insomnia and sleep apnea increase the risk for cognitive decline and possibly dementia. Sleep apnea is a potentially serious disorder in which breathing repeatedly stops and starts during sleep.
This new study suggests that RLS should also be considered as a sleep-related risk factor for dementia, Dang-Vu said.