title: [Case-control study of the risk factors of lumbar intervertebral disc herniation in 5 northern provinces of China].
abstract: OBJECTIVE
  To explore the risk factors of lumbar intervertebral disc herniation in the 5 northern provinces of China.
  
  
  METHODS
  A total of 2010 patients with established diagnosis of lumbar disc herniation by CT and/or MRI and 2170 control subjects without a history of low back pain or sciatica were randomly selected from the community population and hospitalized patients. The family history of lumbar disc herniation, occupations, smoking status, and occupational psychosocial factors were investigated.
  
  
  RESULTS
  The positivity of family history of lumbar disc herniation was the highest risk factor (OR=3.551) followed by lumbar load (OR=2.132) and hard work (OR=1.763). Physical exercises (OR=0.435) were significantly related with the disease, and the OR of the type of bed was 0.364.
  
  
  CONCLUSIONS
  A family history of lumbar disc herniation, lumbar load and hard work are the major risk factors for lumbar disc herniation, and physical exercises and sleeping not in soft bed might be a protective factor against the disease.
authors.affiliation: Department of Orthopedics, Shaanxi Provincial People's Hospital, Xi'an 710068, China. szmnx3@yahoo.cn
authors.forename: Zheng-ming
authors.initials: ZM
authors.lastname: Sun
authors.forename: Ming
authors.initials: M
authors.lastname: Ling
authors.forename: Yan-hai
authors.initials: YH
authors.lastname: Chang
authors.forename: Zong-zhi
authors.initials: ZZ
authors.lastname: Liu
authors.forename: Hong-hai
authors.initials: HH
authors.lastname: Xu
authors.forename: Li-qun
authors.initials: LQ
authors.lastname: Gong
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Yin-gang
authors.initials: YG
authors.lastname: Zhang
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000453:epidemiology*; D008159:Lumbar Vertebrae / Q000473:pathology; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D011795:Surveys and Questionnaires