title: Triggers for an episode of sudden onset low back pain: study protocol.
abstract: BACKGROUND
  Most research on risk factors for low back pain has focused on long term exposures rather than factors immediately preceding the onset of low back pain. The aim of this study is to quantify the transient increase in risk of a sudden episode of low back pain associated with acute exposure to a range of common physical and psychological factors.
  
  
  METHODS
  This study uses a case-crossover design. One thousand adults with a sudden onset of low back pain presenting to primary care clinicians will be recruited. Basic demographic and clinical information including exposure to putative triggers will be collected using a questionnaire. These triggers include exposure to hazardous manual tasks, physical activity, a slip/trip or fall, consumption of alcohol, sexual activity, being distracted, and being fatigued or tired. Exposures in the case window (0-2 hours from the time when participants first notice their back pain) will be compared to exposures in two control time-windows (one 24-26 hours and another 48-50 hours before the case window).
  
  
  CONCLUSIONS
  The completion of this study will provide the first-research based estimates of the increase in risk of a sudden episode of acute low back pain associated with transient exposure to a range of common factors thought to trigger low back pain.
authors.affiliation: Musculoskeletal division, The George Institute for Global Health, Sydney Medical School, The University of Sydney, PO Box M201, Missenden Road, Sydney, New South Wales 2050, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Steffens
authors.forename: Manuela L
authors.initials: ML
authors.lastname: Ferreira
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Maher
authors.forename: Jane
authors.initials: J
authors.lastname: Latimer
authors.forename: Bart W
authors.initials: BW
authors.lastname: Koes
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Blyth
authors.forename: Paulo H
authors.initials: PH
authors.lastname: Ferreira
mesh_terms: D000208:Acute Disease; D000328:Adult; D001315:Australia / Q000453:epidemiology; D016022:Case-Control Studies; D015897:Comorbidity / Q000639:trends; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000453:epidemiology* / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D060051:Occupational Injuries / Q000453:epidemiology* / Q000209:etiology* / Q000503:physiopathology; D012107:Research Design; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D011795:Surveys and Questionnaires