title: Does sedentary behavior increase the risk of low back pain? A population-based co-twin study of Spanish twins.
abstract: The relationship between sedentary lifestyle and low back pain (LBP) remains unclear and previous research has not accounted for genetic and early environmental factors.
  
  
  
  Our aim was to investigate if sedentary behavior is associated with the lifetime prevalence of persistent LBP and the risk of developing persistent LBP, care-seeking due to LBP, and activity limiting LBP when genetics and early environmental factors are accounted for.
  
  
  
  Both cross-sectional and longitudinal designs with a within-pair twin case-control were implemented.
  
  
  
  There were 2,148 twins included in the cross-sectional analysis whereas 1,098 twins free of persistent LBP at baseline were included in the longitudinal analysis.
  
  
  
  Sedentary behavior was the explanatory variable. Lifetime prevalence of LBP was the outcome variable in the cross-sectional analysis. The incidence of persistent LBP, care-seeking due to LBP, and activity limiting LBP were the outcome variables for the longitudinal analysis.
  
  
  
  This observational study was supported by a grant in 2012. No competing interests were declared.
  
  
  
  In the cross-sectional analysis, sedentary behavior was slightly associated with an increased prevalence of persistent LBP in females but not in males. This association was not apparent when genetics and early environmental factors were accounted for. We acknowledge that the small sample included in the co-twin analyses have yielded wide confidence intervals, and that caution should be exercised when interpreting and an association may not be ruled out. In the longitudinal analysis, sedentary behavior did not significantly increase the risk of persistent LBP, care-seeking due to LBP, or activity limiting LBP.
  
  
  
  Sedentary behavior is associated with concurrent LBP. However, this association is weak; it only appears in females and decreases when accounting for genetics. Future studies using a twin design with larger samples should be conducted to further test these findings.
authors.affiliation: Discipline of Physiotherapy, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia. Electronic address: abar3926@uni.sydney.edu.au.
authors.forename: Anita B
authors.initials: AB
authors.lastname: Amorim
authors.affiliation: Discipline of Physiotherapy, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Gavin M
authors.initials: GM
authors.lastname: Levy
authors.affiliation: Department of Health Promotion and Health Education, Murcia Health Council, Murcia, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Pérez-Riquelme
authors.affiliation: Discipline of Physiotherapy, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Milena
authors.initials: M
authors.lastname: Simic
authors.affiliation: Discipline of Physiotherapy, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Pappas
authors.affiliation: Discipline of Physiotherapy, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Amabile B
authors.initials: AB
authors.lastname: Dario
authors.affiliation: The George Institute for Global Health, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Manuela L
authors.initials: ML
authors.lastname: Ferreira
authors.affiliation: Murcia Twin Registry, Department of Human Anatomy and Psychobiology, University of Murcia, and IMIB-Arrixaca, Spain.
authors.forename: Eduvigis
authors.initials: E
authors.lastname: Carrillo
authors.affiliation: Discipline of Physiotherapy, University of Málaga, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Luque-Suarez
authors.affiliation: Murcia Twin Registry, Department of Human Anatomy and Psychobiology, University of Murcia, and IMIB-Arrixaca, Spain.
authors.forename: Juan R
authors.initials: JR
authors.lastname: Ordoñana
authors.affiliation: Discipline of Physiotherapy, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Paulo H
authors.initials: PH
authors.lastname: Ferreira
mesh_terms: D016022:Case-Control Studies; D005260:Female; D059647:Gene-Environment Interaction; D006801:Humans; D017116:Low Back Pain / Q000453:epidemiology* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D057185:Sedentary Behavior; D013030:Spain; D014427:Twins
keywords: Epidemiology; Genetics; Low back pain; Physical activity; Sedentary behavior; Twin study