If you find yourself sleepy during your daily activities in your older age, you may need to consider it more than an inconvenience — since the fatigue may indicate you’re at higher risk for developing a condition that can lead to dementia, a new study has found.
Among participants who experienced excessive daytime sleepiness and a lack of enthusiasm, 35.5% developed motoric cognitive risk syndrome compared with 6.7% of people without those problems, according to the study published Wednesday in the journal Neurology.
Motoric cognitive risk syndrome, or MCR, is marked by slow walking speed and complaints of memory problems among older people who don’t already have dementia or a mobility disability. The risk of developing dementia more than doubles in those with this syndrome, which was first described in 2013.
“Previous studies have shown a link between sleep disorders and the risk of dementia,” said first study author Dr. Victoire Leroy, assistant professor of geriatric medicine at Tours University Hospital in France, via email.
But some of those scientific reports examined that link largely at only one point in time, according to the study. Not much has been known about the relationship between certain aspects of poor-quality sleep and pre-dementia syndromes, either, Leroy and the research team wrote — so they wanted to expand the research in this field.
“Establishing the relationship between sleep dysfunction and MCR risk is important because early intervention may offer the best hope for preventing dementia,” the authors said.
Tracking sleep patterns
The findings are based on 445 adults who were age 76 on average and recruited from New York’s Westchester County for the Central Control of Mobility and Aging study, which assesses the cognitive processes and brain mechanisms that regulate mobility in aging. Participants walked on treadmills so their initial gaits could be recorded, then were assessed annually from 2011 to 2018.
The study authors also collected yearly data on participants’ recollections of their sleep quality and quantity in the two weeks leading up to the assessments. Specifically, the team gleaned details within seven components of the Pittsburgh Sleep Quality Index: subjective sleep quality, time it takes to fall asleep, sleep duration, sleep efficiency (ratio of total hours asleep to total hours in bed), sleep disturbances, use of sleep-inducing medication, and daytime dysfunction, such as having trouble staying awake during activities or feeling less enthusiasm to get things done.
Over a follow-up period of roughly three years on average, 36 participants developed motoric cognitive risk syndrome. Compared with “good” sleepers, “poor” sleepers had only a slightly higher risk of MCR. But when the authors considered the seven sleep components separately, only daytime dysfunction was associated with 3.3 times higher risk of MCR.
