title: Risk factors for hospitalization due to lumbar disc disease.
abstract: METHODS
  Prospective cohort study.
  
  
  OBJECTIVE
  To study biomechanical factors in relation to symptomatic lumbar disc disease.
  
  
  BACKGROUND
  The importance of biomechanical factors in lumbar disc disease has been questioned in the past decade and knowledge from large prospective studies is lacking.
  
  
  METHODS
  The study basis is a cohort of 263,529 Swedish construction workers who participated in a national occupational health surveillance program from 1971 until 1992. The workers' job title, smoking habits, body weight, height, and age were registered at the examinations. The occurrence of hospitalization due to lumbar disc disease from January 1, 1987, until December 31, 2003, was collected from a linkage with the Swedish Hospital Discharge Register.
  
  
  RESULTS
  There was an increased risk for hospitalization due to lumbar disc disease for several occupational groups compared with white-collar workers and foremen. Occupational groups with high biomechanical loads had the highest risks, for example, the relative risk for concrete workers was 1.55 (95% confidence interval [CI], 1.29-1.87). A taller stature was consistently associated with an increased risk. The relative risk for a man of 190- to 199-cm height was 1.55 (95% CI, 1.30-1.86) compared with a man being 170- to 179-cm height. Body weight and smoking were also risk factors, but weaker than height. Workers in the age span of 30 to 39 years had the highest relative risk (RR = 1.87; 95% CI, 1.58-2.23) compared with those aged 20 to 29 years, whereas men aged 60 to 65 years had a lower risk (RR = 0.86; 95% CI, 0.68-1.09).
  
  
  CONCLUSIONS
  This study indicates that factors increasing the load on the lumbar spine are associated with hospitalization for lumbar disc disease. Occupational biomechanical factors seem to be important, and a taller stature was consistently associated with an increased risk.
authors.affiliation: Department of Public Health & Clinical Medicine, Occupational and Environmental Medicine, Umeå University, Umeå, Sweden. jens.wahlstrom@envmed.umu.se
authors.forename: Jens
authors.initials: J
authors.lastname: Wahlström
authors.forename: Lage
authors.initials: L
authors.lastname: Burström
authors.forename: Tohr
authors.initials: T
authors.lastname: Nilsson
authors.forename: Bengt
authors.initials: B
authors.lastname: Järvholm
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001827:Body Height; D001835:Body Weight; D060389:Construction Industry; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000453:epidemiology* / Q000209:etiology; D007405:Intervertebral Disc Displacement / Q000453:epidemiology* / Q000209:etiology; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D016272:Occupational Health / Q000706:statistics & numerical data; D011159:Population Surveillance; D011446:Prospective Studies; D018570:Risk Assessment / Q000706:statistics & numerical data; D012307:Risk Factors; D012907:Smoking; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult