title: The association between sleep duration and self-rated health in the Korean general population.
abstract: OBJECTIVE
  Sleep duration is recognized as one of the most common issues in modern society. Self-rated health is a commonly used subjective health measure based on a single question asking individuals to rate their general health on a four- or five-point scale. However, few studies have examined the relationship between sleep duration and self-rated health. Here, we examined the association between sleep duration and poor self-rated health, using a large representative sample of the general Korean adult population.
  
  
  METHODS
  We conducted a cross-sectional study of 15,252 participants in the Korea National Health and Nutrition Examination Survey IV (2007-2009) who were aged 19 years and older. Sleep duration was categorized as ≤ 5, 6, 7, 8, or ≥ 9 hours. The main outcome of interest was poor self-rated health (n = 3,705, 19.7%). Multiple logistic regression analysis was performed to examine the association between sleep duration and self-rated health.
  
  
  RESULTS
  We found both short (≤ 5 h) and long (≥ 9 h) sleep duration to be associated with poor self-rated health independent of sociodemographic, health risk, and health status variables. Compared with 7-h sleep duration, the multivariate odds of poor self-rated health were 1.358 times higher (95% CI 1.167-1.580) with short sleep duration and 1.322 times higher (95% CI 1.091-1.601) with long sleep duration. This association persisted in subgroup analyses of gender, body mass index, and age by gender.
  
  
  CONCLUSIONS
  In a large representative sample of the Korean general adult population, compared with sleep duration of 7 hours, we found a positive association between short and long sleep duration and poor self-rated health in Korean adults. Furthermore, the association between sleep duration and poor self-rated health was consistently present in subgroups divided by gender, age, and BMI.
authors.affiliation: Department of Public Health, Yonsei University, Seoul, Korea ; Institute of Health Services Research, Yonsei University, Seoul, Korea.
authors.forename: Jae-Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Kyung Ran
authors.initials: KR
authors.lastname: Kim
authors.forename: Kyoung Hee
authors.initials: KH
authors.lastname: Cho
authors.forename: Ki-Bong
authors.initials: KB
authors.lastname: Yoo
authors.forename: Jeoung A
authors.initials: JA
authors.lastname: Kwon
authors.forename: Eun-Cheol
authors.initials: EC
authors.lastname: Park
mesh_terms: D000328:Adult; D000367:Age Factors; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D059026:Diagnostic Self Evaluation; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012016:Reference Values; D056910:Republic of Korea; D057566:Self Report; D012737:Sex Factors; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000175:diagnosis; D011795:Surveys and Questionnaires; D013997:Time Factors
keywords: KNHANES; Sleep; age; body mass index (BMI); gender; self-rated health; sleep duration