title: Leg-length discrepancy is associated with low back pain among those who must stand while working.
abstract: BACKGROUND
  Some studies suggest that leg length discrepancy (LLD) is associated with low back pain (LBP) but many have not found such an association leading to conflicting evidence on the role of LLD in LBP.
  
  
  METHODS
  The study population consisted of meat cutters with a standing job and customer service workers with a sedentary job from Atria Suomi Ltd (Nurmo, Finland) who were at least 35 years old and had been working in their jobs for at least 10 years. Leg length of each participant was measured with a laser range meter fixed in a rod, which was holding the scanning head of the ultrasound apparatus. Association of the intensity of LBP (10-cm Visual Analog Scale) with LLD was analysed by linear regression model, while the hurdle model was used in analysing the association of number of days with LBP and days on sick leave during the past year. Associations were adjusted by gender, age, BMI, smoking, depressive feelings and type of work (standing or sedentary job).
  
  
  RESULTS
  The final study population consisted of 114 meat cutters (26 females and 88 males) and 34 customer service workers (30 females and four males). Forty-nine percent of the meat cutters and 44% of the customer service workers had LLD of at least 6 mm, while 16% and 15%, respectively, had LLD of at least 11 mm. In the whole study population, LLD of 6 mm or more was associated with higher intensity of LBP and number of days with LBP. In the stratified analysis, both intensity of LBP and number of days of LBP were associated with LLD among meat cutters but not among customer service workers. The sick leaves during past year were slightly longer among those with LLD 10 mm or more, but the differences were not statistically significant.
  
  
  CONCLUSIONS
  LLD, measured with a laser range meter, was associated with intensity of LBP and self-reported days with LBP during the past year among meat cutters engaged in standing work.
  
  
  BACKGROUND
  ISRCTN11898558--The role of leg length discrepancy in low back pain.
authors.affiliation: Center for Life Course Epidemiology and Systems Medicine, University of Oulu, Oulu, Finland. satu.rannisto@sarastus.fi.|Medical Research Centre Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland. satu.rannisto@sarastus.fi.|Finnish Institute of Occupational Heath, Health and Work Ability, Tampere, Finland. satu.rannisto@sarastus.fi.
authors.forename: Satu
authors.initials: S
authors.lastname: Rannisto
authors.affiliation: Finnish Institute of Occupational Heath, Health and Work Ability, Tampere, Finland. annaleena.okuloff@ttl.fi.|Finnish Social Science Data Archive, University of Tampere, Tampere, Finland. annaleena.okuloff@ttl.fi.
authors.forename: Annaleena
authors.initials: A
authors.lastname: Okuloff
authors.affiliation: Finnish Institute of Occupational Heath, Health and Work Ability, Tampere, Finland. jukka.uitti@ttl.fi.|Clinic of Occupational Medicine, Tampere University Hospital, Tampere, Finland. jukka.uitti@ttl.fi.|School of Health Sciences, University of Tampere, Tampere, Finland. jukka.uitti@ttl.fi.
authors.forename: Jukka
authors.initials: J
authors.lastname: Uitti
authors.affiliation: Center for Life Course Epidemiology and Systems Medicine, University of Oulu, Oulu, Finland. markus.paananen@oulu.fi.|Medical Research Centre Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland. markus.paananen@oulu.fi.
authors.forename: Markus
authors.initials: M
authors.lastname: Paananen
authors.affiliation: School of Management, University of Tampere, Tampere, Finland. pasi-heikki.rannisto@uta.fi.
authors.forename: Pasi-Heikki
authors.initials: PH
authors.lastname: Rannisto
authors.affiliation: Centre for Health and Social Economics, National Institute for Health and Welfare, Helsinki, Finland. antti.malmivaara@thl.fi.
authors.forename: Antti
authors.initials: A
authors.lastname: Malmivaara
authors.affiliation: Center for Life Course Epidemiology and Systems Medicine, University of Oulu, Oulu, Finland. jaro.karppinen@ttl.fi.|Medical Research Centre Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland. jaro.karppinen@ttl.fi.|Finnish Institute of Occupational Heath, Health and Work Ability, Oulu, Finland. jaro.karppinen@ttl.fi.
authors.forename: Jaro
authors.initials: J
authors.lastname: Karppinen
mesh_terms: D000328:Adult; D005260:Female; D019649:Food Industry; D006801:Humans; D007870:Leg Length Inequality / Q000150:complications* / Q000175:diagnosis; D016014:Linear Models; D017116:Low Back Pain / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000209:etiology*; D011187:Posture; D018582:Sick Leave