title: Risk factors for low back pain: insights from a novel case-control twin study.
abstract: BACKGROUND
  Previous research has failed to identify strong consistent risk factors for low back pain (LBP). A plausible solution is to conduct hypothesis-generating studies, such as twin case-control surveys.
  
  
  OBJECTIVE
  To investigate twins' perceptions of the factors responsible for within-pair differences in LBP.
  
  
  METHODS
  A case-control twin survey.
  
  
  METHODS
  Twenty-four twin pairs that were generally and broadly discordant for LBP history.
  
  
  METHODS
  The participants' perceptions of the factors that could explain within-pair differences in LBP history.
  
  
  METHODS
  Twins were asked to identify the factors responsible for within-pair differences in LBP. Closed questioning collected information on the known risk factors and open-ended questioning was used to reveal novel factors. The frequency of risk factors was presented to investigate the individual's perception of the contribution of factors in the development of their own and/or their twin's experience of LBP.
  
  
  RESULTS
  The most frequent factors reported in the closed questioning related to the physical workload of the lumbar spine, specifically, the engagement in different types of work (n=23/24 pairs, 96%). Types of work included those involving heavy loads, lifting, manual tasks, awkward postures, and gardening. Single trauma or injury and vigorous physical activity participation were perceived as the contributors by 79% (n=19/24 pairs) and 88% (n=21/24 pairs) of the pairs, respectively. Open-ended questioning did not reveal new risk factors for LBP.
  
  
  CONCLUSIONS
  Twins attributed the differences in LBP history to risk factors related to physical workload. Future studies investigating the risk factors for LBP should include valid and comprehensive assessments of these factors.
authors.affiliation: Departamento de Fisioterapia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil. Electronic address: viniciuscunhaoliveira@yahoo.com.br.
authors.forename: Vinicius C
authors.initials: VC
authors.lastname: Oliveira
authors.affiliation: The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia; Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Manuela L
authors.initials: ML
authors.lastname: Ferreira
authors.affiliation: Faculty of Health Sciences, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Refshauge
authors.affiliation: The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia; Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Chris G
authors.initials: CG
authors.lastname: Maher
authors.affiliation: Faculty of Health Sciences, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Alexandra R
authors.initials: AR
authors.lastname: Griffin
authors.affiliation: Australian Twin Registry, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: John L
authors.initials: JL
authors.lastname: Hopper
authors.affiliation: Faculty of Health Sciences, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Paulo H
authors.initials: PH
authors.lastname: Ferreira
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000453:epidemiology / Q000209:etiology*; D008159:Lumbar Vertebrae; D008297:Male; D017063:Outcome Assessment, Health Care; D011187:Posture; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014427:Twins
keywords: Case-control survey; Epidemiology; Low back pain; Prevention; Risk factors; Twin study