In the study of 1,982 older adults in China who were free of dementia at the start of the study, 97 participants were diagnosed with dementia during an average follow-up of 3.7 years.
Risk of dementia was 69% higher in those who slept for more than 8 hours (versus 7-8 hours) and 2-times higher for those who went to bed before 9 PM (versus 10 PM or later).
“This suggests that cognitive function should be monitored in older adults who report prolonged 102time in bed and advanced sleep timing,” the authors wrote.