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Physical and psychosocial ergonomic risk factors for low back pain in automobile manufacturing workers
  1. Jonathan L Vandergrift1,
  2. Judith E Gold1,
  3. Alexandra Hanlon1,2,
  4. Laura Punnett3
  1. 1Department of Public Health, Temple University, Philadelphia, Pennsylvania, USA
  2. 2Department of Family and Community Medicine, School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  3. 3Department of Work Environment, University of Massachusetts Lowell, Lowell, Massachusetts, USA
  1. Correspondence to Jonathan L Vandergrift, National Comprehensive Cancer Network, 275 Commerce Drive, Suite 300, Fort Washington, PA 19034, USA; vandergrift{at}


Objectives To examine the association between ergonomic physical and psychosocial exposures and the risk of prevalent and incident low back pain (LBP) in a longitudinal cohort of automobile manufacturing workers.

Methods Ergonomic exposure intensity and LBP presence were determined through questionnaires at baseline (n=1181) and to workers in the same job 1 year later (n=505). Models were constructed using log-binomial regression with special attention to interactions between ergonomic exposures.

Results Awkward back posture (prevalence ratio (PR) 1.12, 95% CI 1.07 to 1.17), hand force (PR 1.06, 95% CI 1.02 to 1.10), physical effort (PR 1.10, 95% CI 1.04 to 1.16) and whole body vibration (PR 1.04, 95% CI 1.01 to 1.08) were each associated cross-sectionally with LBP. Awkward back posture (RR 1.13, 95% CI 0.98 to 1.31) and hand force (RR 1.07, 95% CI 0.93 to 1.22) also predicted incident LBP, although estimates were statistically less precise. Neither job control, psychological demands, nor job strain was independently related to risk of incident LBP. Among participants reporting high physical ergonomic exposures and moderate to high job control, increasing job demands was associated with a reduced LBP risk (RR 0.72, 95% CI 0.52 to 1.00). Among participants reporting high physical exposures and low job control, psychological demands was associated with an increased LBP risk (RR 1.30, 95% CI 1.02 to 1.66).

Conclusions Psychosocial workplace interventions for LBP should prioritise jobs in which there are high physical ergonomic exposures. Future studies of LBP should examine the interactions between physical ergonomic risk factors.

  • Job strain
  • interaction
  • ergonomics
  • epidemiology

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  • Funding This research was supported by the National Joint Committee on Health and Safety jointly sponsored by the manufacturing company involved and the United Automobile Workers. This manuscript is solely the responsibility of the authors and does not necessarily represent the official views of any other agency or institution.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.