Those who have trouble falling asleep within 30 minutes may be at a higher risk for developing dementia, a new study has suggested.
The research, which was published in the American Journal of Preventive Medicine, also found that sleep medication use was associated with a higher risk. Scientists set out to find if there were links between sleep disturbance and dementia.
The study looked at a nationally representative group of US adults aged 65 or over and examined 10 years' worth of data from the National Health and Aging Trends Study.
The lead investigator was Roger Wong; PhD, MPH, MSW and Assistant Professor in the Department of Public Health and Preventive Medicine, SUNY Upstate Medical University, New York.
The researchers found that trouble falling asleep in 30 minutes and medication use were both linked with a higher risk of the cognitive disease. However, they also found that those who have trouble falling back to sleep after waking were less likely to develop dementia over the course of the study.
While the reason for decreased risk among this group is still unknown, the investigators theorise that they may engage in activities that preserve or increase cognitive reserve. "We expected sleep-initiation insomnia and sleep medication usage to increase dementia risk, but we were surprised to find sleep-maintenance insomnia decreased dementia risk," Dr. Wong said.
"The motivation behind this research was prompted on a personal level. My father has been experiencing chronic sleep disturbances since the COVID-19 pandemic began, and I was concerned how this would affect his cognition in the future.
"After reading the existing literature, I was surprised to see mixed findings on the sleep-dementia relationship, so I decided to investigate this topic."
The researchers believe they have found potential preventative lifestyle changes which could reduce dementia risk.
"By focusing on the variations in sleep disturbances, our findings can help to inform lifestyle changes that can reduce dementia risk," explained co-investigator Margaret Anne Lovier, MPH, Department of Public Health and Preventive Medicine, SUNY Upstate Medical University, New York.
It comes after previous research has associated REM sleep behaviour, less than five hours of sleep, and the use of short-acting benzodiazepines with cognitive decline.
Recent evidence indicates there is a higher prevalence of sleep disturbances among older adults than among other age groups. This could be attributed to a variety of factors.
"Older adults are losing sleep over a wide variety of concerns. More research is needed to better understand its causes and manifestations and limit the long-term consequences," added Dr. Wong.
"Our findings highlight the importance of considering sleep disturbance history when assessing the dementia risk profile for older adults.
"Future research is needed to examine other sleep disturbance measures using a national longitudinal sample, whether these sleep-dementia findings hold true for specific dementia subtypes, and how certain sociodemographic characteristics may interact with sleep disturbances to influence dementia risk."
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