Excessive Sleeping May Be Early Marker of Dementia

MedicalResearch.com Interview with:

Dr. Matthew P. Pase Sidney Sax NHMRC Fellow, Department of Neurology Boston University School of Medicine Investigator, Framingham Heart Study;  Senior Research Fellow, Swinburne University of Technology. Boston MA 02118

Dr. Matthew Pase

Dr. Matthew P. Pase
Sidney Sax NHMRC Fellow, Department of Neurology
Boston University School of Medicine

Investigator, Framingham Heart Study;
Senior Research Fellow, Swinburne University of Technology.
Boston MA 02118

MedicalResearch.com: What is the background for this study?

Response: Sleep disturbances are common in dementia. However, most studies have focused on patients who already have dementia and so it is unclear whether disturbed sleep is a symptom or a cause of dementia.

We studied 2,457 older participants enrolled in the Framingham Heart Study, a large group of adults sampled from the community in Framingham, Massachusetts. We asked participants to indicate how long they typically slept each night. Participants were then observed for the following 10-years to determine who developed dementia, including dementia due to Alzheimer’s disease. Over the 10 years, we observed 234 cases of dementia. Information on sleep duration was then examined with respect to the risk of developing dementia.

MedicalResearch.com: What are the main findings?

Response: We observed that persons who reported sleeping for over 9 hours each night had double the risk of developing dementia in 10 years as compared to participants who slept for 9 hours or less; they also had smaller brain volumes as determined using brain MRI.

We also examined participants past sleeping habits and found that persons who consistently slept for over 9 hours each night did not display an increased risk of dementia. In contrast, persons who recently transitioned to becoming long sleepers displayed an increased risk of dementia. Long sleepers who were without a high school degree displayed a 6-fold increase in the risk of dementia as compared to those who slept for 9 hours or less each night. Short sleep duration (<6 hours) was not associated with an increased risk of dementia relative to persons sleeping 6-9 hours.

MedicalResearch.com: What should readers take away from your report?

Response: Our findings suggest that long sleep duration may sometimes result from brain changes that occur early in dementia, with changes in sleep detected before dementia diagnosis. In other words, excessive sleep may sometimes be a marker but not a cause of early dementia. Therefore, interventions to restrict sleep duration are unlikely to reduce the risk of dementia. Rather, screening for sleeping problems may aid in the early detection of cognitive impairment and dementia. Older persons recently reporting becoming excessive sleepers who also complain of problems with thinking or memory may warrant assessment and monitoring.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: Different aspects of sleep may serve different functions in the brain. Future research is needed to examine whether there are any specific aspects of sleep that become abnormal before dementia onset. Our team is currently examining this question using more detailed overnight sleep studies known as polysomnography.

Doctors Pase and Seshadri have no disclosures.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.


Prolonged sleep duration as a marker of early neurodegeneration predicting incident dementia” by Andrew J. Westwood, Alexa Beiser, Nikita Jain, Jayandra J. Himali, Charles DeCarli, Sanford H. Auerbach, Matthew P. Pase, and Sudha Seshadri in Neurology. Published online February 22 2017 doi:10.1212/WNL.0000000000003732

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