Alzheimer's Linked To Poor Sleep
October 22, 2013

Possible Link Between Poor Sleep And Alzheimer’s

Michael Harper for - Your Universe Online

A new study published in JAMA Neurology has found a possible association between poor sleep and Alzheimer’s disease. Though the researchers at The Johns Hopkins Bloomberg School of Public Health have found indications of this link, they’re not yet sure if poor sleep increases one’s risk of developing Alzheimer’s or vice versa.

Build ups of beta amyloid plaque have been found to be a precursor to Alzheimer’s disease. After using brain scans to peer into aging brains, Professor Adam P. Spira and colleagues noticed that those who reported getting the least sleep also had the highest build up of these plaques. Recent studies have also shown that stress may be linked to Alzheimer’s in women.

“These results could have significant public health implications as Alzheimer’s disease is the most common cause of dementia, and approximately half of older adults have insomnia symptoms,” Spira told Reuters. "We've known for a long time that people with Alzheimer's disease have really disturbed sleep patterns. People have wondered, well, is it possible that poor sleep is actually leading to cognitive decline?"

Dr. Spira gathered 70 volunteers aged 53 to 91 who filled out extensive questionnaires and underwent brain scans. The research team first asked these study participants how many hours they slept each night, either no more than five or no more than seven. They also asked them how often they woke up during the night and if they had their sleep disrupted by any other causes.

Next the researchers looked for the presence of beta amyloid plaque build up in the brain. These protein clusters have been found in Alzheimer’s patients in higher quantities than in individuals with healthy, normally functioning brains.

On average the amount of plaque build up increased significantly with every hour of sleep lost, said Dr. Spira. Additionally, every point they scored on the low sleep quality test earned them an increase in plaque build up. As a way to test the results, Dr. Spira removed four of the participants who had developed Alzheimer’s during the test. Even after these subjects were missing, the team still found a statistically significant increase in amyloid plaque build up in those who reported having low quality or fewer hours of sleep.

Though they’ve noted a link, Dr. Spira and team say they’re not yet ready to declare that poor quality and little sleep are necessarily precursors to or causes of Alzheimer’s.

“In summary, our findings in a sample of community-dwelling older adults indicate that reports of shorter sleep duration and poorer sleep quality are associated with a greater Αβ burden. As evidence of this association accumulates, intervention trials will be needed to determine whether optimizing sleep can prevent or slow AD progression,” concludes the study.

Previous studies have also noted a link between sleep and Alzheimer's but have been hesitant to call it a direct causal relationship. For instance, a report was presented at the 2013 American Thoracic Society International Conference in May which linked poor sleep quality to sleep apnea and other disorders. The researchers from the University of Wisconsin urged other researchers to investigate the sharp increase of sleep apnea in elderly patients.