Sleep quality predicts preclinical Alzheimer’s disease
medwireNews: Poor sleep quality is associated with the early signs of amyloid deposition and may therefore predict preclinical Alzheimer's disease (AD), researchers report.
They found that cognitively normal individuals with cerebrospinal fluid (CSF) β-amyloid (Aβ)42 levels of 500 pg/mL or less, indicating a high likelihood for amyloid deposition, had significantly worse sleep quality, as measured by sleep efficiency, than those without amyloid deposition.
"If sleep disruption increases risk of future AD, then this provides an even stronger motivation to identify and treat individuals with sleep disorders, such as obstructive sleep apnea," say David Holtzman (Washington University School of Medicine, St Louis, Missouri, USA) and colleagues.
They believe that amyloid accumulation negatively affects sleep-wake behaviors, and conversely, poor sleep may increase risk for amyloid aggregation.
For the study, published in JAMA Neurology, a total of 142 individuals aged 45 years and older provided valid actigraphy data. Of these, 32 (22.5%) had a CSF Aβ42 levels of 500 pg/mL or less.
Patients with amyloid deposition had significantly worse sleep efficiency than those without amyloid deposition, at 80.4% versus 83.7%. After taking into account age, gender, and apolipoprotein Eε4 allele carrier status, the difference between the two groups was significant.
By contrast, the two groups did not differ with regard to sleep quantity, although there was a trend for patients with amyloid deposition to spend an increased time in bed, which the researchers suggest may be to compensate for poorer sleep efficiency and thereby leading them to obtain the same overall total sleep time as those without amyloid deposition.
The participants with amyloid deposition were also more likely to nap during the daytime than their peers without amyloid deposition, with 31.2% versus 14.7% taking naps on 3 or more days per week.
When Holtzman and team looked specifically at the worst sleepers, with a sleep efficiency below 75%, they found them to be more than five times more likely to have amyloid deposition than the best sleepers with a sleep efficiency above 89%.
The findings suggest that "sleep measures… could be used as markers of brain function, thereby facilitating faster and easier clinical trials of promising treatments in the preclinical and early clinical stages of AD," the researchers conclude.
By Lucy Piper, Senior medwireNews Reporter