Prolonged Sleep Duration as Marker of Early Neurodegeneration Predicting Dementia

Neurology. 2017 Feb 22. pii: 10.1212/WNL.0000000000003732. doi:[Epub ahead of print]

Prolonged sleep duration as a marker of early neurodegeneration predicting incident dementia.

Westwood AJ1, Beiser A1, Jain N1, Himali JJ1, DeCarli C1, Auerbach SH1, Pase MP2, Seshadri S2.

Abstract

OBJECTIVE

To evaluate the association between sleep duration and the risk of incident dementia and brain aging.

METHODS

Self-reported total hours of sleep were examined in the Framingham Heart Study (n = 2,457, mean age 72 ± 6 years, 57% women) as a 3-level variable: <6 hours (short), 6-9 hours (reference), and >9 hours (long), and was related to the risk of incident dementia over 10 years, and cross-sectionally to total cerebral brain volume (TCBV) and cognitive performance.

RESULTS

We observed 234 cases of all-cause dementia over 10 years of follow-up. In multivariable analyses, prolonged sleep duration was associated with an increased risk of incident dementia (hazard ratio [HR] 2.01; 95% confidence interval [CI] 1.24-3.26). These findings were driven by persons with baseline mild cognitive impairment (HR 2.83; 95% CI 1.06-7.55) and persons without a high school degree (HR 6.05; 95% CI 3.00-12.18).

Transitioning to sleeping >9 hours over a mean period of 13 years before baseline was associated with an increased risk of all-cause dementia (HR 2.43; 95% CI 1.44-4.11) and clinical Alzheimer disease (HR 2.20; 95% CI 1.17-4.13). Relative to sleeping 6-9 hours, long sleep duration was also associated cross-sectionally with smaller TCBV (β ± SE, -1.08 ± 0.41 mean units of TCBV difference) and poorer executive function (β ± SE, -0.41 ± 0.13 SD units of Trail Making Test B minus A score difference).

CONCLUSIONS

Prolonged sleep duration may be a marker of early neurodegeneration and hence a useful clinical tool to identify those at a higher risk of progressing to clinical dementia within 10 years.

Citation

http://www.neurology.org/content/early/2017/02/22/WNL.0000000000003732.short?sid=9c5c9bbb-0ca2-4b2d-afc8-fdf6bdff8b7e

© 2017 American Academy of Neurology.