Total daily sleep duration and the risk of dementia: a prospective population-based study
Article first published online: 31 MAR 2009
© 2009 The Author(s). Journal compilation © 2009 EFNS
European Journal of Neurology
Volume 16, Issue 9, pages 990–997, September 2009
How to Cite
Benito-León, J., Bermejo-Pareja, F., Vega, S. and Louis, E. D. (2009), Total daily sleep duration and the risk of dementia: a prospective population-based study. European Journal of Neurology, 16: 990–997. doi: 10.1111/j.1468-1331.2009.02618.x
- Issue published online: 7 AUG 2009
- Article first published online: 31 MAR 2009
- Received 27 November 2008 Accepted 18 February 2009
- incident dementia;
- sleep duration
Background and purpose: We determined in a population-based study whether sleep duration was associated with an increased risk of incident dementia.
Methods: In a population-based study in central Spain, participants were evaluated at baseline and 3 years later. Baseline demographic variables were recorded and participants indicated their daily sleep duration as the sum of night-time sleep and daytime napping. The average daily total sleep duration was grouped into five categories: ≤5 (short sleepers), 6, 7 (reference), 8, and ≥9 h (long sleepers). We identified all cases with incident dementia, diagnosed using DSM-IV criteria.
Results: Three thousand two hundred eighty six participants with baseline information about sleep duration had a median duration of follow-up of 3.2 years. There were 140 incident cases of dementia. The relative risks (RR) for short sleepers and for long sleepers were 2.36 (95% CI = 1.07–5.21, P = 0.03) and 2.40 (95% CI = 1.20–4.81, P = 0.01), respectively. After adjustment for potential confounders, the RR was only marginally increased for short sleepers (1.87, 95% CI = 0.85–4.15, P = 0.12) but remained increased for long sleepers (2.18; 95% CI = 1.09–4.37, P = 0.03).
Conclusions: Prolonged sleep duration (night-time sleep and daytime napping) may be associated with an increased risk of dementia.