Older man napping, sleep, home
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Irregular sleep patterns — not sticking to a regular sleep-wake schedule — may put people at a higher risk for dementia compared to those with more consistent sleep patterns, according to a new report released Wednesday in Neurology. 

Authors of the report emphasized that their findings don’t state that inconsistent sleep causes dementia; it shows an association, they said. 

“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,” Matthew Paul Pase, PhD, a researcher from Monash University in Melbourne, Australia, said in a statement. “Our findings suggest the regularity of a person’s sleep is an important factor when considering a person’s risk of dementia.”

The team evaluated sleep patterns from 88,094 people in the UK. The average age of participants was 62 years old. Over the course of seven years, the researchers followed their sleep patterns. Each participant wore a device on their wrist to gauge sleep data.

The researchers pinpointed the likelihood of being in the same sleep state — asleep or awake — at any two time points 24 hours apart over an average of seven days. For instance, people who woke and fell asleep at the exact time each day would have a sleep regularity index of 100; someone who went to bed and woke up at different times of the day would have a zero.

When the researchers looked at medical data to see who eventually developed dementia, they found 480 people had the disorder. Next, the team went back to see if there were any associations between a person’s sleep regularity index and their disease state.

Compared to those with an average sleep regularity index, a person’s dementia risk was highest in those who had the most irregular sleep. People in the lowest fifth percentile had the most irregular sleep with an average sleep regularity score of 41. Those in the highest 95th percentile had the most regular sleep with an average score of 71. In between those groups, the average sleep index was 60. 

After the team adjusted data based on age, sex and genetic risk of Alzheimer’s disease, they found that those with the most erratic sleep schedules were 53% more likely to develop dementia compared to those in the middle group.