title: Independent effect of physical workload and childhood socioeconomic status on low back pain among health care workers in Denmark.
abstract: METHODS
  Prospective cohort study.
  
  
  OBJECTIVE
  To investigate the independent effect of physical workload and childhood socioeconomic status (CSES) on low back pain (LBP) and LBP-related sickness absence among female health care workers.
  
  
  BACKGROUND
  The role of physical workload on LBP independently from CSES is still subject to controversy.
  
  
  METHODS
  We used questionnaire data from 1661 female social and health care workers responding to a questionnaire in 2004, 2005, and 2006. We collected information on CSES (parental occupation), physical workload, and LBP-prevalence (no LBP, subchronic LBP, and frequent LBP), and LBP-related sickness absence. The participants were categorized into 5 groups according to CSES (I = highest, V = lowest). Data were analyzed using logistic regression analysis.
  
  
  RESULTS
  Irrespective of CSES, high physical workload increased the odds ratio (OR) of future subchronic LBP (OR = 2.03; 95% confidence interval [CI], 1.61-2.57) and frequent LBP (OR = 2.20; 95% CI, 1.65-3.00), but not LBP-related sickness absence. The odds of subchronic LBP were lower in CSES groups II (OR = 0.62; 95% CI, 0.42-0.93) and III (OR = 0.58; 95% CI, 0.39-0.86) referencing CSES group I, irrespective of physical workload. The odds of short-term LBP-related sickness absence were higher in CSES groups III (OR = 2.78; 95% CI, 1.41-5.47) and IV (OR = 2.18; 95% CI, 1.11-4.27) referencing CSES group I, irrespective of physical workload. We found no interaction between physical workload and CSES.
  
  
  CONCLUSIONS
  Physical workload and CSES are independently associated with future LBP within a group with similar occupational status.
  
  
  METHODS
  N/A.
authors.affiliation: The National Research Centre for the Working Environment, 2100 Copenhagen, Denmark. mbj@nrcwe.dk
authors.forename: Marie Birk
authors.initials: MB
authors.lastname: Jørgensen
authors.forename: Kirsten
authors.initials: K
authors.lastname: Nabe-Nielsen
authors.forename: Thomas
authors.initials: T
authors.lastname: Clausen
authors.forename: Andreas
authors.initials: A
authors.lastname: Holtermann
mesh_terms: D000328:Adult; D002648:Child; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006282:Health Personnel / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D017116:Low Back Pain / Q000453:epidemiology* / Q000209:etiology; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D018582:Sick Leave / Q000706:statistics & numerical data; D012923:Social Class; D011795:Surveys and Questionnaires; D016526:Workload; D055815:Young Adult