title: Short sleep duration across income, education, and race/ethnic groups: population prevalence and growing disparities during 34 years of follow-up.
abstract: OBJECTIVE
  Little is known about population determinants of short sleep duration. The authors examined associations between short sleep duration and income, education and race/ethnicity, and assessed changes over time in relative disparities.
  
  
  METHODS
  Questionnaire data from the Alameda County Health and Ways of Living Study (ACS) was obtained at five time-points (1965, 1974, 1983, 1994, and 1999) for short sleep duration (<7 hours sleep per night). Household income, education level, and race/ethnicity were assessed at baseline (n = 6,928). Odds ratios were computed to examine short sleep duration across income, education and race/ethnicity, adjusting for age, sex and time-varying covariates, and to assess changes over time.
  
  
  RESULTS
  Prevalence of short sleep at baseline was 15.2%. The (age-adjusted) odds of short sleep was increased for the lowest household income quintile (odds ratio [OR], 1.62; 95% confidence interval [CI], 1.34-1.94), those with less than high school education (OR, 1.51; 95% CI, 1.30-1.75), and among African Americans (OR, 1.97; 95% CI, 1.68-2.30). Relative disparities increased over time for African-American and Hispanic, compared with white, participants.
  
  
  CONCLUSIONS
  Socioeconomic position is a robust determinant of short sleep duration, even after adjusting for health-related characteristics linked to short sleep duration.
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA. kstamatakis@jhu.edu
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Stamatakis
authors.forename: George A
authors.initials: GA
authors.lastname: Kaplan
authors.forename: Robert E
authors.initials: RE
authors.lastname: Roberts
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012893:Sleep Wake Disorders / Q000453:epidemiology* / Q000208:ethnology; D012959:Socioeconomic Factors