Association of sleep duration with Alzheimer's disease and cognition

INTRODUCTION: The association of sleep duration with Alzheimer's disease (AD) - related brain atrophy and cognition remains unclear. METHODS: Among 38,816 participants in the UK Biobank, we examined the association between sleep duration and a validated machine-learning-derived magnetic resonance imaging (MRI) signature of AD-related atrophy (Spatial Pattern of Abnormality for Recognition of Early AD [SPARE-AD]) and three cognitive test scores using generalized additive models. Independently, electronic health records (EHR) from TriNetX were used to examine the 10-year AD risk associated with insomnia and hypersomnia. RESULTS: Sleep duration exhibited a U-shaped association with SPARE-AD (p = 0.001), Trail Making Tests A and B, and the Digit Symbol Substitution Test (all p < 0.001). Short (5-6 hours) and long (9-10 hours) sleep duration were associated with poorer cognitive performance. Both insomnia and hypersomnia showed a high risk for Alzheimer's disease. CONCLUSION: This study demonstrates a U-shaped association between sleep duration and AD-like atrophy and cognition. DISCUSSION: These findings show that excessive or insufficient sleep is linked to worse brain health.