title: Race and financial strain are independent correlates of sleep in midlife women: the SWAN sleep study.
abstract: OBJECTIVE
  To examine racial differences in sleep in a large cohort of midlife women and to evaluate whether indices of socioeconomic status (SES) are associated with racial differences in sleep.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Participants' homes.
  
  
  METHODS
  Caucasian (n=171), African American (n=138) and Chinese women (n=59).
  
  
  METHODS
  None.
  
  
  METHODS
  Sleep quality was assessed with the Pittsburgh Sleep Quality Index. Polysomnographically assessed sleep duration, continuity, architecture, and NREM electroencephalograhic (EEG) power were calculated over multiple nights. Sleep disordered breathing and periodic leg movements were measured on a separate night. Linear regression analysis was used to model the independent and synergistic effects of race and SES on sleep after adjusting for other factors that impact sleep in midlife women. Indices of SES were self-reported educational attainment and financial strain.
  
  
  RESULTS
  Sleep was worse in African American women than Caucasian participants as measured by self-report, visual sleep stage scoring, and NREM EEG power. Slow wave sleep differences were also observed between Chinese and Caucasian participants. Racial differences persisted after adjustment for indices of SES. Although educational attainment was unrelated to sleep, financial strain was associated with decreased sleep quality and lower sleep efficiency. Financial strain-by-race interactions were not statistically significant, suggesting that financial strain has additive effects on sleep, independent of race.
  
  
  CONCLUSIONS
  Independent relationships between race and financial strain with sleep were observed despite statistical adjustment for other factors that might account for these relationships. Results do not suggest that assessed indices of SES moderate the race-sleep relationship, perhaps due to too few women of low SES in the study.
authors.affiliation: Department of Psychiatry University of Pittsburgh, Pittsburgh, PA 15213, USA. hallmh@upmc.edu
authors.forename: Martica H
authors.initials: MH
authors.lastname: Hall
authors.forename: Karen A
authors.initials: KA
authors.lastname: Matthews
authors.forename: Howard M
authors.initials: HM
authors.lastname: Kravitz
authors.forename: Ellen B
authors.initials: EB
authors.lastname: Gold
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Buysse
authors.forename: Joyce T
authors.initials: JT
authors.lastname: Bromberger
authors.forename: Jane F
authors.initials: JF
authors.lastname: Owens
authors.forename: MaryFran
authors.initials: M
authors.lastname: Sowers
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data*; D001213:Asian / Q000706:statistics & numerical data*; D003430:Cross-Sectional Studies; D005260:Female; D005583:Fourier Analysis; D006306:Health Surveys; D006801:Humans; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D020189:Nocturnal Myoclonus Syndrome / Q000175:diagnosis / Q000453:epidemiology / Q000208:ethnology*; D017286:Polysomnography; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000208:ethnology*; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000208:ethnology*; D012959:Socioeconomic Factors; D044465:White People / Q000706:statistics & numerical data*