• Posted December 14, 2023

Irregular Sleep Is Tied to a Higher Odds for Dementia

People who maintain a mostly regular sleep pattern could have a lower risk of developing dementia than those whose sleeping and waking times vary wildly, a new study finds.

People with the most irregular sleep are 53% more likely to develop dementia than people with average sleep regularity, researchers report in the Dec. 13 issue of the journal Neurology.

This suggests that consistency when it comes to knocking off for the night and rising in the morning contributes to brain health, said researcher Matthew Pase, an associate professor of psychology at Monash University in Australia.

“Sleep health recommendations often focus on getting the recommended amount of sleep, which is seven to nine hours a night, but there is less emphasis on maintaining regular sleep schedules,” Pase said in a journal news release. “Our findings suggest the regularity of a person's sleep is an important factor when considering a person's risk of dementia.”

For the study, Pase and his colleagues tracked more than 88,000 people with an average age of 62 in the United Kingdom. The participants were followed for an average of seven years.

Participants wore a wrist device for seven days that measured their sleep cycle, which allowed researchers to calculate the regularity of their sleep.

A perfect sleep regularity index of 100 would involve a person who sleeps and wakes at the exact time each day, while an index of zero would involve someone whose sleep and wake times are always different.

People in this study with the most irregular sleep had an average score of 41, and the most regular sleep scores averaged around 71, results show.

Participants between those two groups had an average sleep regularity score of 60.

Researchers then evaluated medical data to identify which of the participants went on to develop dementia, and found that 480 people had suffered brain decline.

People with the most irregular sleep were more likely to develop dementia than average sleepers, researchers found.

However, they also discovered that the folks with the best regular sleep did not have a lower risk of dementia than those in the average group.

That means people don't have to achieve machine-like sleep rhythms to get the benefits of regular sleep cycles, researchers said.

However, the study could only show an association between an irregular sleeping schedule and a greater risk of dementia.

“Effective sleep health education combined with behavioral therapies can improve irregular sleep patterns,” Pase said. “Based on our findings, people with irregular sleep may only need to improve their sleep regularity to average levels, compared to very high levels, to prevent dementia. Future research is needed to confirm our findings.”

More information

Harvard Medical School has more about sleep and dementia risk.

SOURCE: American Academy of Neurology, news release, Dec. 13, 2023