Overview

• Researchers report the risk increase is roughly equivalent to 3.5 additional years of brain aging, with faster drops on cognitive tests among those with insomnia.
• The cohort tracked 2,750 cognitively healthy adults (average age about 70) for roughly 5.6 years, with 14% of those with insomnia developing mild cognitive impairment or dementia versus 10% without.
• Imaging linked shorter recent sleep to more white matter hyperintensities and amyloid plaques, while sleeping more than usual correlated with fewer white matter changes.
• Participants carrying the APOE ε4 genetic risk factor experienced the steepest declines when insomnia was present.
• The authors emphasize the findings are associative and based on medical-record diagnoses, and clinicians recommend assessment and CBT-I for persistent insomnia, with CNN reporting less detriment in those who increased sleep time or used medication.