Usual sleep duration and cognitive function in older adults in Spain

Authors

  • RAQUEL FAUBEL,

    1. Department of Preventive Medicine and Public Health, School of Medicine, Universidad Autónoma de Madrid, CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
    Search for more papers by this author
  • ESTHER LÓPEZ-GARCÍA,

    1. Department of Preventive Medicine and Public Health, School of Medicine, Universidad Autónoma de Madrid, CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
    Search for more papers by this author
  • PILAR GUALLAR-CASTILLÓN,

    1. Department of Preventive Medicine and Public Health, School of Medicine, Universidad Autónoma de Madrid, CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
    Search for more papers by this author
  • AUXILIADORA GRACIANI,

    1. Department of Preventive Medicine and Public Health, School of Medicine, Universidad Autónoma de Madrid, CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
    Search for more papers by this author
  • JOSÉ R. BANEGAS,

    1. Department of Preventive Medicine and Public Health, School of Medicine, Universidad Autónoma de Madrid, CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
    Search for more papers by this author
  • FERNANDO RODRÍGUEZ-ARTALEJO

    1. Department of Preventive Medicine and Public Health, School of Medicine, Universidad Autónoma de Madrid, CIBER in Epidemiology and Public Health (CIBERESP), Madrid, Spain
    Search for more papers by this author

Dr Fernando Rodríguez-Artalejo, Departamento de Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, 2, 28029 Madrid, Spain. Tel.: +34 91 497 5444; fax: +34 91 497 5353; e-mail: fernando.artalejo@uam.es

Summary

The few studies that have examined the association between usual sleep duration and cognitive function have shown conflicting results. This cross-sectional study examined the association between sleep duration and cognitive function among 3212 people, representative of the non-institutionalized population aged 60 years and over in Spain. Sleep duration was self-reported, and cognitive function was measured with the Mini-Examen Cognoscitivo (MEC), a version of the Mini-Mental State Examination that has been validated in Spain. Linear regression, with adjustment for the main confounders, was used to obtain mean differences in the MEC between the categories of sleep duration (≤5, 6, 7, 8, 9, 10, ≥11 h day−1). The MEC score decreased progressively (became worse) across sleep categories from 7 to ≥11 h (P for linear trend <0.001). People who slept for ≥11 h had a significantly lower MEC score than those who slept for 7 h (mean difference −1.48; 95% confidence interval −2.12 to −0.85). This difference in the MEC was similar to that observed for a 10-year increase in age. The results did not vary significantly by sex (P for interaction >0.05). No association was observed between short sleep duration (<7 h) and cognitive function. We conclude that long sleep duration is associated with poorer cognitive function in older adults from the general population.

Ancillary