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A new study, which explored the link between sleep and dementia risk, found that women over the age of 80 who had increasing sleepiness during the day showed a higher risk for dementia, according to authors of a study published Wednesday in Neurology.
Investigators evaluated 733 women who were 83 years old on average. None of the women had mild cognitive impairment or dementia at the start of the study. Participants wore wrist-based devices to track their sleep and circadian rhythm patterns for three days at the start and end of the study. The team placed participants into three groups: 44% were considered as having stable sleep or small improvements in sleep, 35% had declining nighttime sleep and 21% had increasing sleepiness, 21%.
The team then tied sleep changes to the risk of developing dementia. After five years, 56% of participants had changes in sleep patterns, 22% developed mild cognitive impairment and 13% developed dementia. Among those in the stable sleep group, 8% developed dementia. In the declining nighttime sleep group, 15% developed dementia. In the increasing sleepiness group, 19% developed dementia.
After adjusting for different factors like age and education, the team found that participants in the group that had increasing sleepiness in the day had double the risk of dementia compared to those in the stable sleep group. Researchers didn’t note an association in the declining nighttime sleep group.
“We observed that sleeping, napping and circadian rhythms can change dramatically over only five years for women in their 80s,” Yue Leng, PhD, a researcher from the University of California, San Francisco, said in a statement. “This highlights the need for future studies to look at all aspects of daily sleep patterns to better understand how changes in these patterns over time can be linked to dementia risk.”