Total daily sleep duration and the risk of dementia: A prospective population-based study

J. Benito-León, F. Bermejo-Pareja, S. Vega, E. D. Louis

Research output: Contribution to journalArticlepeer-review

114 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)990-997
Number of pages8
JournalEuropean Journal of Neurology
Issue number9
StatePublished - Sep 2009
Externally publishedYes


  • Elderly
  • Epidemiology
  • Incident dementia
  • Sleep duration

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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