Associations of Chronic Insomnia, Longitudinal Cognitive Outcomes, Amyloid-PET, and White Matter Changes in Cognitively Normal Older Adults

BACKGROUND AND OBJECTIVES: The relationship between insomnia and cognitive decline is poorly understood. We investigated associations between chronic insomnia, longitudinal cognitive outcomes, and brain health in older adults. METHODS: From the population-based Mayo Clinic Study of Aging, we identified cognitively unimpaired older adults with or without a diagnosis of chronic insomnia who underwent annual neuropsychological assessments (z-scored global cognitive scores and cognitive status) and had quantified serial imaging outcomes (amyloid-PET burden [centiloid] and white matter hyperintensities from MRI [WMH, % of intracranial volume]). We used mixed-effects models to examine associations between baseline insomnia (independently or with interaction with self-reported changes in habitual sleep duration) and longitudinal cognitive z-scores, log-transformed WMH, and amyloid-PET levels while adjusting for multiple confounders, including sleep apnea diagnosis. The risk of incident cognitive impairment (CI) was estimated using the Cox proportional hazards model. RESULTS: = 0.832). DISCUSSION: We found an association between insomnia, cognitive decline, and increased risk for CI. Insomnia with reduced sleep was associated with worse cognitive performance and poorer brain health (WMH and amyloid burden) at baseline. Sleeping more than usual was associated with lower WMH burden.