Is increased sleepiness in 80s tied to higher dementia risk?

A study in Neurology, led by Yue Leng, PhD, and Sasha Milton, followed the sleep patterns of 733 older female participants to see if specific patterns of change were associated with a higher risk of dementia. The participants, whose average age was 83, were monitored by wrist devices that track movement and time spent asleep. They had normal cognition at the start of the study.

At the end of the study, five years later, 13% had developed dementia. This included 25 participants (8%) with stable sleep patterns, 39 (15%) with declining nighttime sleep patterns and 29 (19%) with increasing sleepiness. After adjusting for factors like age, education, diabetes and hypertension, those with increasing sleepiness had double the risk of the stable sleepers.

This study is one of the first to look at how sleep patterns change over time and relate to dementia risk. It adds to a body of recent UCSF-led research that shows poor sleep quality in midlife, delayed dream phase and extended napping are linked to a higher risk of dementia.

It is unknown if worsening sleep increases the risk of dementia or if dementia leads to worsening sleep. Some scientists believe both theories may be correct. 

Reference:

Sasha Milton, Clémence Cavaillès Five-Year Changes in 24-Hour Sleep-Wake Activity and Dementia Risk in Oldest Old Women, https://doi.org/10.1212/WNL.0000000000213403