title: Self-reported sleep patterns in a British population cohort.
abstract: OBJECTIVE
  Sleep patterns have been linked to various health outcomes, but sleep patterns in the British population have not been extensively reported. We aimed to describe the sleep characteristics reported by the European Prospective Investigation of Cancer (EPIC)-Norfolk participants, with a particular emphasis on the comparison of measures of sleep quantity.
  
  
  METHODS
  From 2006 to 2007, a total of 8480 participants aged 45-90 years reported sleep timing, nighttime sleep duration, and sleep difficulties. Time in bed (TIB) was calculated from the difference between rise time and bedtime, and sleep proportion was defined as the ratio of sleep duration and TIB.
  
  
  RESULTS
  On average, the reported TIB was more than 1.5h longer than sleep durations. Compared to men, women spent 15 min longer in bed, but they slept for 11 min less and reported more sleep difficulties. In multivariate analysis sleep duration and TIB varied with socioeconomic factors, but sleep proportion was consistently lower among women, nonworkers, and older individuals, as well as those who were widowed, separated, or divorced; those who reported sleep difficulties and more frequently used sleep medication; and those who had lower education, poorer general health, or a major depressive disorder (MDD).
  
  
  CONCLUSIONS
  Self-reported sleep duration and TIB have different meanings and implications for health. Sleep proportion may be a useful indicator of sleep patterns in the general population.
authors: Department of Public Health and Primary Care, Strangeways Research Laboratory, University of Cambridge, Cambridge, UK. Electronic address: yl411@cam.ac.uk.
authors: Yue
authors: Y
authors: Leng
authors: Department of Public Health and Primary Care, Strangeways Research Laboratory, University of Cambridge, Cambridge, UK.
authors: Nick W J
authors: NW
authors: Wainwright
authors: Division of Mental Health and Well-being, Warwick Medical School, University of Warwick, Coventry, UK.
authors: Francesco P
authors: FP
authors: Cappuccio
authors: Department of Public Health and Primary Care, Strangeways Research Laboratory, University of Cambridge, Cambridge, UK.
authors: Paul G
authors: PG
authors: Surtees
authors: Department of Public Health and Primary Care, Strangeways Research Laboratory, University of Cambridge, Cambridge, UK.
authors: Robert
authors: R
authors: Luben
authors: Medical Research Council Epidemiology Unit, Institute of Metabolic Science, Cambridge, UK.
authors: Nick
authors: N
authors: Wareham
authors: Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge, Cambridge, UK.
authors: Carol
authors: C
authors: Brayne
authors: Department of Public Health and Primary Care, Strangeways Research Laboratory, University of Cambridge, Cambridge, UK.
authors: Kay-Tee
authors: KT
authors: Khaw
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D017533:Marital Status; D008875:Middle Aged; D057566:Self Report; D012737:Sex Factors; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000453:epidemiology; D012959:Socioeconomic Factors; D013997:Time Factors; D006113:United Kingdom / Q000453:epidemiology
keywords: England; Epidemiology; Population; Sleep patterns; Sleep quantity; Sleep research