Sleep Disturbances and Dementia Risk in Older Adults: Findings From 10 Years of National US Prospective Data

Introduction: Previous research has identified a link between sleep disturbances and cognitive impairment; however, no study has examined this relationship using a national United States sam-ple. This study examines how multiple longitudinal measures of sleep disturbances (sleep-initiation insomnia, sleep-maintenance insomnia, sleep-medication usage) are associated with dementia risk.Methods: Ten annual waves (2011-2020) of prospective cohort data from a nationally representa-tive U.S. sample of adults aged >= 65 years were analyzed from the National Health and Aging Trends Study. Sleep disturbances were converted into a longitudinal score and measured as sleep -initiation insomnia (trouble falling asleep in 30 minutes), sleep-maintenance insomnia (trouble falling asleep after waking up early), and sleep-medication usage (taking medication to help sleep). Cox regression models analyzed time to dementia diagnosis for a sample of 6,284 respondents.Results: In the unadjusted model, sleep-initiation insomnia was significantly associated with a 51% increased dementia risk (hazard ratio=1.51, 95% CI=1.19, 1.90). Adjusted for sociodemo-graphics, sleep-medication usage was significantly associated with a 30% increased dementia risk (adjusted hazard ratio=1.30, 95% CI=1.08-1.56). Adjusted for sociodemographics and health, sleep-maintenance insomnia was significantly associated with a 40% decreased dementia risk (adjusted hazard ratio=0.60, 95% CI=0.46, 0.77).Conclusions: These findings suggest that sleep-initiation insomnia and sleep-medication usage may elevate dementia risk. On the basis of the current evidence, sleep disturbances should be con-sidered when assessing the risk profile for dementia. Future research is needed to examine other sleep disturbance measures and to explore the mechanisms for decreased dementia risk among older adults with sleep-maintenance insomnia.Am J Prev Med 2023;64(6):781-787. (c) 2023 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Automated summary

Previous research has shown a link between sleep disturbances and cognitive impairment, but this study is the first to examine this relationship using a national sample from the United States. The study found that sleep-initiation insomnia and sleep-medication usage may increase the risk of dementia, while sleep-maintenance insomnia may decrease the risk.