Reported at the Alzheimer’s Association International Conference 2017 (AAIC 2017) in London, these findings highlight the idea that sleep disordered breathing is a modifiable factor that may help lower the risk of dementia and possibly slow the progression of dementia where it already exists.
Researchers at Wheaton College, Illinois, examined sleep patterns among participants to characterise potential effects of sleep disordered breathing and obstructive sleep apnoea (OSA) on brain changes associated with mild cognitive impairment and Alzheimer’s disease.
The researchers examined accumulation of the amyloid protein in the brain (one of the key hallmarks of Alzheimer’s disease) in 516 people who didn’t have any memory or thinking problems. They found that those with sleep disordered breathing had higher levels of amyloid at baseline and more rapid accumulation over time. They didn’t find an association between the Alzheimer’s risk gene APOE-e4 and sleep apnoea, suggesting the effects of OSA are separate to this gene.
Further analyses assessed the effects of OSA in 798 subjects with mild cognitive impairment (MCI). Again, both baseline amyloid levels and the rate of accumulation were higher in people with OSA. While MCI does not always lead to dementia, a person with MCI is at an increased risk of developing Alzheimer’s or another dementia. These results suggest that sleep disordered breathing may be a risk factor for Alzheimer’s and raises the possibility that interventions aimed at treating sleep disordered breathing may also reduce Alzheimer’s risk.
Dr Doug Brown, Director of Research and Development at Alzheimer’s Society, said:
‘Researchers are increasingly finding associations between the early physical signs of Alzheimer’s disease and poor quality sleep, but we don’t know whether poor sleep directly increases your risk of Alzheimer’s.
‘These new studies add to the evidence already out there that there is a link between sleep disorders like sleep apnoea and signs of Alzheimer’s. But we still don’t know whether or not people with sleep disorders will go on to develop Alzheimer’s disease. These studies all relied on people self-reporting their sleep, and only looked at a snapshot in time. We need to see further studies that measure sleep in the clinic, and that follow people over a long period of time to understand whether problems with sleep do actually increase the risk of Alzheimer’s disease.
‘As certain sleep disorders can be treatable, the next stage is to test some of these treatments in a controlled research setting to understand whether they could be effective in reducing the risk of dementia.
‘It’s important to talk to your GP if you have a sleep disorder and are concerned about your health.’