Sleeping 9 hours or more linked to greater dementia risk

The following is from an article in the Medical news Today and was written by Ana Sandoiu for the full article go here

For this study, a large number of adults enrolled in the Framingham Heart Study ( were asked to report how long they usually slept per night. The researchers then clinically followed the participants for 10 years to see who developed Alzheimer's disease and other forms of dementia.

Boston University School of Medicine (BUSM) researchers then examined the data collected on sleep duration and calculated the risk of developing dementia.

The team found that people who sleep regularly for 9 hours or more were twice as likely to develop Alzheimer's within 10 years, compared with those who consistently slept less than 9 hours.

Additionally, as the study's lead author explains, education seems to be playing a role in staving off the risk of dementia.

"Participants without a high school degree who sleep for more than 9 hours each night had six times the risk of developing dementia in 10 years as compared [with] participants who slept for less. These results suggest that being highly educated may protect against dementia in the presence of long sleep duration." Dr. Sudha Seshadri

The study also found that people who slept longer seemed to have smaller brain volumes. Being observational, the study cannot establish causality, but the researchers suspect excessive sleep is probably a symptom rather than a cause of the neuronal changes that come with dementia. As a consequence, they speculate, reducing sleep duration is not likely to lower the risk of dementia.

The authors believe the findings may inform future dementia and cognitive impairment detection practices. Co-corresponding author Matthew Pase, Ph.D., who is a fellow in the department of neurology at BUSM and investigator at the FHS, weighs in on the significance of the findings.

"Self-reported sleep duration may be a useful clinical tool to help predict persons at risk of progressing to clinical dementia within 10 years," he says. "Persons reporting long sleep time may warrant assessment and monitoring for problems with thinking and memory."

The sooner a patient is diagnosed with dementia, the more time they and their families have to plan ahead and make crucial healthcare decisions.