Investigators found that sleep-disordered breathing increased the accumulation rate of brain β-amyloid in cognitively normal persons and in individuals with mild cognitive impairment. Another study found that obstructive sleep apnea (OSA) was associated with increased brain β-amyloid deposition, decreased cerebrospinal fluid (CSF) levels of β-amyloid, and increased tau protein levels.
Researchers at Wheaton College in Illinois conducted 3 studies that examined sleep patterns among participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI) to characterize the potential effects of sleep-disordered breathing and OSA on brain changes associated with mild cognitive impairment and Alzheimer's disease.
In one study, Amanda Shim and colleagues examined brain β-amyloid-42 (Aβ42) accumulation in 516 cognitively normal subjects and found that those with sleep-disordered breathing had higher levels of CSF at baseline and a more rapid accumulation over time. No interactive effect was observed between OSA and APOE-e4, a risk gene for Alzheimer’s disease, suggesting that OSA may be independently associated with brain amyloid burden.
Megan Hogan and colleagues assessed the effects of OSA in 798 subjects with mild cognitive impairment (MCI). Similar to the cognitively normal cohort, baseline β-amyloid-42 levels and the rate of accumulation were higher in patients with OSA. These results, according to the investigators, suggest that sleep-disordered breathing may be an independent risk factor for Alzheimer’s disease and that interventions aimed at treating sleep-disordered breathing may also lower the risk for Alzheimer's disease.
The results “highlight the importance of checking for, and accurately diagnosing, sleep-disordered breathing, especially in people at risk for dementia, and more importantly in people diagnosed with MCI, so that it can be addressed and treated,” said research team leader Omonigho Bubu, MD, MPH.