title: Sleep duration among black and white Americans: results of the National Health Interview Survey.
abstract: BACKGROUND
  Epidemiologic studies have shown the importance of habitual sleep duration as an index of health and mortality risks. However, little has been done to ascertain ethnic differences in sleep duration in a national sample. This study compares sleep duration in a sample of black and white participants in the National Health Interview Survey (NHIS).
  
  
  METHODS
  Data were collected from 29,818 Americans (age range 18-85 years) who participated in the 2005 NHIS. The NHIS is a cross-sectional household interview survey that uses a multistage area probability design, thus permitting representative sampling of U.S. households. During face-to-face interviews conducted by trained interviewers from the U.S. Census Bureau, respondents provided demographic data and information about physician-diagnosed chronic conditions, estimated habitual sleep duration and functional capacity, and rated their mood.
  
  
  RESULTS
  Fisher's exact test results indicated that blacks were less likely than whites to report sleeping 7 hours (23% vs. 30%; chi2 = 94, p < 0.0001). Blacks were more likely to experience both short sleep (< or = 5 hours) (12% vs. 8%, chi2 = 44, p < 0.0001) and long sleep (> or = 9 hours) (11% vs. 9%, chi2 = 23, p < 0.0001). Logistic regression analysis, adjusting for differences in sociodemographic factors, depression, functional capacity and medical illnesses, demonstrated that black ethnicity was a significant predictor of extreme sleep duration (Wald = 46, p < 0.0001; OR = 1.35, 95% CI: 1.24-1.47).
  
  
  CONCLUSIONS
  Independent of several sociodemographic and medical factors, blacks had more prevalent short and long sleep durations, suggesting greater variation in habitual sleep time. Therefore, blacks might be at increased risks of developing medical conditions associated with short and long sleep.
authors.affiliation: Sophie Davis School of Biomedical Education, City College, New York, NY, USA.
authors.forename: Joao
authors.initials: J
authors.lastname: Nunes
authors.forename: Girardin
authors.initials: G
authors.lastname: Jean-Louis
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Zizi
authors.forename: Georges J
authors.initials: GJ
authors.lastname: Casimir
authors.forename: Hans
authors.initials: H
authors.lastname: von Gizycki
authors.forename: Clinton D
authors.initials: CD
authors.lastname: Brown
authors.forename: Samy I
authors.initials: SI
authors.lastname: McFarlane
mesh_terms: D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011594:Psychometrics; D012307:Risk Factors; D012890:Sleep; D012892:Sleep Deprivation; D012893:Sleep Wake Disorders / Q000453:epidemiology* / Q000523:psychology; D011795:Surveys and Questionnaires; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data*