Less time spent in rapid eye movement sleep was associated with increased risk for incident dementia, according to recent findings.
“Different stages of sleep may differentially affect key features of Alzheimer’s disease. Our findings implicate REM sleep mechanisms as predictors of dementia,” Matthew P. Pase, PhD, of Boston University School of Medicine, said in a press release.
To assess associations between sleep architecture and risk for incident dementia, researchers evaluated a subset of 321 Framingham Heart Study participants who completed the Sleep Heart Health Study between 1995 and 1998 and were aged older than 60 years at sleep assessment. Home polysomnography determined sleep stages. Participants were followed for up to 19 years.
There were 32 cases of incident dementia and 24 were consistent with Alzheimer’s disease dementia.
When adjusting for age and sex, lower REM sleep percentage and longer REM sleep latency were associated with increased risk for incident dementia.
For each percentage reduction in REM sleep, risk for incident dementia increased by approximately 9% (HR = 0.91; 95% CI, 0.86-0.97),
The association between REM sleep percentage and dementia remained when adjusting for vascular risk factors, depressive symptoms and medication use, and excluding participants with mild cognitive impairment at baseline and early converters to dementia.
Non-REM sleep stages were not associated with dementia risk.
“It is possible that reduced REM sleep may be a marker of increased responsiveness to stress, with heightened anxiety also implicated as a risk factor for dementia,” the researchers wrote. “On the other hand, REM sleep is thought to promote synaptic consolidation and to upregulate the activity of immediate early genes implicated in synaptic plasticity. Thus, REM sleep may also buffer against synaptic loss and cognitive decline by assisting in the production of new connections and networks. Though there are biologically plausible mechanisms to explain our results, more studies are needed to explore the mechanisms linking REM sleep to [Alzheimer’s disease] pathology and incident dementia.” – by Amanda Oldt
Disclosure: Pase reports no relevant financial disclosures. Please see the study for a full list of relevant financial disclosures.