title: Long working hours and sleep problems among public junior high school teachers in Japan.
abstract: OBJECTIVE
  Long working hours may impact human health. In Japan, teachers tend to work long hours. From 2002 to 2012, the number of leaves of absence due to diseases other than mental disorders, or mental disorders among public school teachers increased by 1.3 times (from 2,616 to 3,381), or 1.8 times (from 2,687 to 4,960), respectively. The present study aimed to investigate the association between long working hours and sleep problems among public school teachers.
  
  
  METHODS
  This cross-sectional study was conducted from mid-July to September 2013 in Hokkaido Prefecture, Japan. Questionnaires were distributed to 1,245 teachers in public junior high schools. Information about basic characteristics including working hours, and responses to the Pittsburgh Sleep Quality Index were collected anonymously. Multiple logistic regression analysis was used to calculate odds ratios (ORs) for the association between long working hours and sleep problems separately by sex.
  
  
  RESULTS
  The response rate was 44.8% (n=558). After excluding ineligible responses, the final sample comprised 515 teachers (335 males and 180 females). Sleep problems was identified in 41.5% of males and 44.4% of females. Our results showed a significantly increased risk of sleep problems in males working >60 hours per week (OR 2.05 [95% CI 1.01-4.30]) compared with those working ≤40 hours per week. No significant association was found in females.
  
  
  CONCLUSIONS
  There is a significant association between long working hours and sleep problems in male teachers. Reducing working hours may contribute to a reduction in sleep problems.
authors.affiliation: Department of Public Health, Hokkaido University Graduate School of Medicine.
authors.forename: Akira
authors.initials: A
authors.lastname: Bannai
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Ukawa
authors.forename: Akiko
authors.initials: A
authors.lastname: Tamakoshi
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005178:Faculty; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology / Q000209:etiology*; D012737:Sex Factors; D012893:Sleep Wake Disorders / Q000453:epidemiology / Q000209:etiology*; D013997:Time Factors; D014940:Work Schedule Tolerance; D055815:Young Adult