An astonishing report from researchers at the Boston University Medical Center has come to a surprising conclusion about dementia: sleep habits could predict that you have it. Specifically, the study claims that if you’re sleeping for more than nine hours, you could be suffering from an early form of the degenerative brain disease.

Scientists found that people who spend this much time in bed or longer were twice as likely to develop dementia over the next 10 years comapred to those who slep less than that. Changes in sleep patterns are a big indication that there has been damage to the brain, researchers say.

It’s an important finding that could yield critical insights into how to treat the condition. The study is based on an examination of 2,400 people, who were followed for a decade and self-reported their sleep duration. If confirmed, it would provide a new way to spot dementia early.

“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 to participants who slept for less. These results suggest that being highly educated may protect against dementia in the presence of long sleep duration,” explained co-corresponding author Sudha Seshadri, MD, professor of neurology at BUSM and FHS senior investigator.

“Self-reported sleep duration may be a useful clinical tool to help predict persons at risk of progressing to clinical dementia within 10 years. Persons reporting long sleep time may warrant assessment and monitoring for problems with thinking and memory,” added co-corresponding author Matthew Pase, PhD, fellow in the department of neurology at BUSM and investigator at the FHS.