Insomnia may increase the risk of memory loss in middle-aged and elderly adults

An analysis of the Canadian Longitudinal Study on Aging suggests that middle-aged and older adults with insomnia face an increased likelihood of developing subjective memory loss compared to their peers who have few or no symptoms of insomnia.

“Since sleep is important for memory consolidation and other cognitive functions, disrupted sleep likely makes cognition more vulnerable,” Thanh Dang-Vu, MD, PhD, professor and research chair at Concordia University in Sleep, Neuroimaging, and Cognitive Health in Montreal, Quebec, Canada, told dasherz.org | Medscape Cardiology.

Previous studies have shown that subjective memory problems are associated with a greater risk of progression to mild cognitive impairment or dementia.

The current analysis, published online on July 25 in Sleepshowed that people without insomnia symptoms (NIS) who developed a probable insomnia disorder (PID) within 3 years were more than one and a half times more likely to experience self-reported memory deterioration than people who had insomnia symptoms only ( ISO) or remained NIS.

Worsening of sleep, deterioration of memory

Dang-Vu and colleagues analyzed 2019 data from 26,363 people (mean age 65.5; about half women; 96% white). Participants were categorized as having PID, ISO, or NIS based on sleep questionnaires. The follow-up was 3 years (2022).

Only those who had difficulty falling asleep or staying asleep 3 or more times per week for more than 3 months and who reported that it significantly interfered with their daily functioning and was unsatisfactory were classified as having PID patients.

At follow-up, subjective measures of memory were obtained through self-report questions; objective measures of cognitive performance were obtained through neuropsychological testing.

Across the sample, 66.45% of participants with NIS at baseline remained so at follow-up; 30.92% switched to ISO and 2.63% to PID.

Of those with ISO at baseline, 30.31% remained ISO, 67.22% converted to NIS, and 2.46% converted to PGD.

Of those with PID at baseline, 2.88% had persistent PID, 33.12% returned to ISO, and 64% to NIS.

NIS participants who developed PID at follow-up had an increased likelihood of self-reported memory impairment compared to those who developed ISO or remained NIS (odds ratio [OR]1.70).

In addition, those whose sleep worsened from baseline to follow-up—ie, transitioned from NIS to ISO, NIS to PID, or ISO to PID—had an increased likelihood (OR, 1.22) of subjective memory deterioration at follow-up im Compared to those who remained free from insomnia or improved their sleep.

There were no significant associations between the development of PGD or worsening sleep and neuropsychological test performance. However, objective memory deficits were found in men who developed PID, suggesting a possible gender effect that the authors say needs further investigation.

screen and treatment

“Screening for sleep disorders should be part of the routine evaluation of patients with cognitive disorders,” said Dang-Vu. “Besides insomnia, for example, obstructive sleep apnea is associated with an increased risk of cognitive decline and poorer performance in several domains such as memory, attention, and executive functioning.”

Alon Y. Avidan, MD, MPH, professor of neurology at the University of California, Los Angeles, and director of the UCLA Sleep Disorders Center, agrees that “being able to screen patients and knowing their sleep quality is critical.”

“A large proportion of the population suffers from chronic insomnia, and it’s common among older adults with much higher prevalence, especially around the time of the pandemic,” he said Medscape Medical News.

Although the study is an observational study, he said, “This is important new information that will help us understand the impact of chronic insomnia disorder on neurological and neurocognitive function and provide additional insight.”

dr Alon Avidan

“Can you say that if you have chronic insomnia, you will get dementia? Probably not. We don’t have that smoking gun yet,” he said. “But the trend is that it’s not healthy [the] brain of not getting enough sleep.

“If I had a patient asking what to do after hearing these results, I would first tell them to always let me know about their sleep quality because if they have insomnia, I want to know about it.

“Second, we need to find out what contributes to the correlates or signs of insomnia,” he said. “Is it blue light before bed? Are your thoughts racing? Do they have other conditions like restless legs syndrome or obstructive sleep apnea that need to be validated by a sleep study?

“The third is working on solutions,” he said. “Most people go to their pharmacy and start buying drugs. And these drugs, unfortunately, will not be the solution, and many will have more side effects than benefits. Decide if the patient is really a candidate for a drug or if they would be an even better candidate for cognitive behavioral therapy (CBT) on how we should treat insomnia in every patient.”

Dang-Vu came to a similar conclusion regarding treatment, and his team is currently investigating whether CBT for insomnia or other non-pharmacological interventions could benefit cognitive function in older adults.

Dang-Vu and Avidan did not report any relevant disclosures.

Sleep. Published July 25, 2022. Summary.

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