Scientists from Concordia University found that older people with insomnia are at greater risk of developing memory decline and long-term cognitive impairment such as dementia.
They used data from more than 26,000 participants of the Canadian Longitudinal Study on Aging, all aged between 45 and 85.
The researchers compared completed self-reported evaluations of sleep and memory and neuropsychological testing in several cognitive domains from 2019 and a follow-up in 2022.
Participants who reported worsening sleep quality in that three-year interval also had greater odds of reporting subjective memory decline.
They found that insomnia specifically was related to worse memory performance compared to those who have some insomnia symptoms alone or no sleep problems at all. This deficit in memory was specific.
Insomnia has been classified as a psychological disorder in the Diagnostic and Statistical Manual of Mental Disorders, the primary reference handbook used by physicians worldwide.
A diagnosis of insomnia requires symptoms of difficulty falling asleep, staying asleep or waking too early three nights a week over a period of three months.
Additionally, those with insomnia must report that this sleep problem causes them difficulty in the daytime.
For this study, the researchers grouped their subjects into one of three categories: those who reported no sleep problems, those who had some insomnia symptoms, and those who developed probable insomnia.
When they looked at the data from the 2022 follow-up, those who had reported a worsening of sleep quality—from no symptoms to some or probable insomnia, or from some symptoms to probable insomnia—were more likely to report memory decline or have it diagnosed by their physician.
They were also more likely to show a higher prevalence of anxiety, depression, daytime sleepiness, breathing interruptions during sleep, other sleep-related issues, smoking, and a greater body mass index (BMI) score.
All of these are considered risk factors for cognitive decline and dementia. Additionally, the study found that men with insomnia perform worse on memory tests than women, suggesting that older men may be at greater risk.
This study highlights the importance of properly diagnosing and managing insomnia as early as possible in older adults.
Adequately treating insomnia disorder might become an important preventive measure for cognitive decline and mitigate the incidence of dementia in later life.
If you care about sleep, please read studies about exercise that can help you sleep better and common drug for sleep problems may harm cognitive functions.
For more information about sleep, please see recent studies about the cause of sleepiness in Alzheimer’s disease, and results showing this new drug could reduce symptoms of sleep apnea.
The research was published in the journal Sleep and conducted by Nathan Cross et al.
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