title: Is objectively measured sitting time associated with low back pain? A cross-sectional investigation in the NOMAD study.
abstract: BACKGROUND
  Studies on the association between sitting time and low back pain (LBP) have found contrasting results. This may be due to the lack of objectively measured sitting time or because socioeconomic confounders were not considered in the analysis.
  
  
  OBJECTIVE
  To investigate the association between objectively measured sitting time (daily total, and occupational and leisure-time periods) and LBP among blue-collar workers.
  
  
  METHODS
  Two-hundred-and-one blue-collar workers wore two accelerometers (GT3X+ Actigraph) for up to four consecutive working days to obtain objective measures of sitting time, estimated via Acti4 software. Workers reported their LBP intensity the past month on a scale from 0 (no pain) to 9 (worst imaginable pain) and were categorized into either low (≤ 5) or high (> 5) LBP intensity groups. In the multivariate-adjusted binary logistic regression analysis, total sitting time, and occupational and leisure-time sitting were both modeled as continuous (hours/day) and categorical variables (i.e. low, moderate and high sitting time).
  
  
  RESULTS
  The multivariate logistic regression analysis showed a significant positive association between total sitting time (per hour) and high LBP intensity (odds ratio; OR = 1.43, 95%CI = 1.15-1.77, P = 0.01). Similar results were obtained for leisure-time sitting (OR = 1.45, 95%CI = 1.10-1.91, P = 0.01), and a similar but non-significant trend was obtained for occupational sitting time (OR = 1.34, 95%CI 0.99-1.82, P = 0.06). In the analysis on categorized sitting time, high sitting time was positively associated with high LBP for total (OR = 3.31, 95%CI = 1.18-9.28, P = 0.03), leisure (OR = 5.31, 95%CI = 1.57-17.90, P = 0.01), and occupational (OR = 3.26, 95%CI = 0.89-11.98, P = 0.08) periods, referencing those with low sitting time.
  
  
  CONCLUSIONS
  Sitting time is positively associated with LBP intensity among blue-collar workers. Future studies using a prospective design with objective measures of sitting time are recommended.
authors: Department of Musculoskeletal Disorders, National Research Centre for the Working Environment, Copenhagen, Denmark.
authors: Nidhi
authors: N
authors: Gupta
authors: Department of Musculoskeletal Disorders, National Research Centre for the Working Environment, Copenhagen, Denmark.
authors: Caroline Stordal
authors: CS
authors: Christiansen
authors: Department of Occupational and Public Health Sciences, Centre for Musculoskeletal Research, University of Gävle, Gävle, Sweden.
authors: David M
authors: DM
authors: Hallman
authors: Department of Musculoskeletal Disorders, National Research Centre for the Working Environment, Copenhagen, Denmark.
authors: Mette
authors: M
authors: Korshøj
authors: Department of Musculoskeletal Disorders, National Research Centre for the Working Environment, Copenhagen, Denmark.
authors: Isabella Gomes
authors: IG
authors: Carneiro
authors: Department of Musculoskeletal Disorders, National Research Centre for the Working Environment, Copenhagen, Denmark.
authors: Andreas
authors: A
authors: Holtermann
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007899:Leisure Activities; D016015:Logistic Models; D017116:Low Back Pain / Q000209:etiology*; D008297:Male; D009784:Occupational Diseases / Q000209:etiology; D011187:Posture / Q000502:physiology*; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013995:Time