title: Disabling low back pain associated with night shift duration: sleep problems as a potentiator.
abstract: BACKGROUND
  We investigated how night shift duration and sleep problems were jointly associated with disabling low back pain (LBP) among workers in different occupations.
  
  
  METHODS
  An online-survey was conducted regarding work schedules, disabling LBP, sleep problems, and other relevant factors in 5,008 workers who were randomly selected from a market research panel. Multiple logistic regression analyses determined the joint associations of night shift duration (0 [permanent day shift], <8, 8-9.9, 10-15.9, ≥16 hr) and sleep problems (no, yes) with disabling LBP adjusted for potential confounders.
  
  
  RESULTS
  A night shift ≥16 hr was associated with a significant increase in the likelihood of disabling LBP. The magnitude of this association was elevated when participants perceived sleep problems including both sleep duration and quality.
  
  
  CONCLUSIONS
  Associations between extended night shifts and disabling LBP became stronger in the presence of short or poor quality sleep.
authors.affiliation: National Institute of Occupational Safety and Health, Tama-ku, Kawasaki, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Medical Research and Management for Musculoskeletal Pain, 22nd Century Medical and Research Center, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.|Clinical Research Center for Occupational Musculoskeletal Disorders, Kanto Rosai Hospital, Nakahara-ku, Kawasaki, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Matsudaira
authors.affiliation: Department of Mental Health, The University of Tokyo, Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Shimazu
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D016015:Logistic Models; D017116:Low Back Pain / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000209:etiology*; D009790:Occupations / Q000706:statistics & numerical data*; D012307:Risk Factors; D012890:Sleep; D020178:Sleep Disorders, Circadian Rhythm / Q000150:complications*; D011795:Surveys and Questionnaires; D013997:Time Factors; D014940:Work Schedule Tolerance; D055815:Young Adult
keywords: insomnia symptoms; musculoskeletal disorders; shift schedules; sleep duration