A comparison of approaches to modeling the relationship between ergonomic exposures and upper extremity disorders

Am J Ind Med. 2000 Jun;37(6):645-55. doi: 10.1002/(sici)1097-0274(200006)37:6<645::aid-ajim9>3.0.co;2-#.


Background: For a study of upper extremity musculoskeletal disorders among automobile manufacturing workers, an ergonomic exposure index was constructed by summing ten psychophysical (interview) items. Here we explore the sensitivity of the exposure-response relationship to the formulation of that index.

Methods: Five alternative exposure indices were constructed: three a priori weighting schemes and two sets of weights derived from multivariate regression coefficients. In addition, structural equation modeling was performed with LISREL.

Results: The original index and a priori weighting schemes had similar associations with upper extremity disorders, adjusted for nonoccupational covariates. A reasonable model fit was achieved in LISREL after two modifications; the standardized solution showed that nonneutral postures were significantly related to upper extremity signs and symptoms.

Conclusions: In this large population, with adequate range of exposures, the exposure-response relationship appeared generally robust to the mathematical formulation of the exposure index. Among the available exposure variables, postural strain had the strongest association.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Arm Injuries / etiology*
  • Automobiles*
  • Computer Simulation
  • Ergonomics*
  • Female
  • Humans
  • Industry*
  • Male
  • Middle Aged
  • Musculoskeletal Diseases / etiology*
  • Occupational Diseases / etiology*
  • Psychophysics
  • Risk Factors