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Total daily sleep duration and the risk of dementia: a prospective population-based study |
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| Authors: | J Benito-León F Bermejo-Pareja S Vega E D Louis |
| Institution: | Department of Neurology, University Hospital '12 de Octubre', Madrid, Spain;;Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED);;'El Espinar' Health Center, El Espinar, Segovia, Spain;;Department of Neurology, The G.H. Sergievsky Center, College of Physicians and Surgeons, Columbia University;;Department of Neurology, College of Physicians and Surgeons, Columbia University;;Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University;;and Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA |
| Abstract: | 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. |
| Keywords: | elderly epidemiology incident dementia sleep duration |