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A case-crossover study of laceration injuries in pork processing
  1. Lina Lander1,
  2. Gary Sorock2,
  3. Terry L Stentz3,4,
  4. Lynette M Smith5,
  5. Murray Mittleman6,7,
  6. Melissa J Perry7,8
  1. 1Department of Epidemiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
  2. 2Springfield Hospital Center, Sykesville, Maryland, USA
  3. 3College of Engineering, University of Nebraska–Lincoln, Lincoln, Nebraska, USA
  4. 4Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Nebraska USA
  5. 5Department of Biostatistics, University of Nebraska Medical Center, Omaha, Nebraska, USA
  6. 6Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA
  7. 7Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
  8. 8Department of Environmental and Occupational Health, The George Washington University, Washington, DC, USA
  1. Correspondence to Dr Lina Lander, Assistant Professor, Department of Epidemiology, College of Public Health, University of Nebraska Medical Center, 984395 Nebraska Medical Center, Omaha, NE 68198-4395, USA; llander{at}


Objectives The authors estimated the associations between transient risk factors and laceration injuries in workers at two meatpacking plants in the Midwest.

Methods The case-crossover design was used to collect within-subject transient work task and personal-level exposure information. RRs of laceration injuries were estimated by comparing exposures during the ‘hazard’ period (just before the laceration injury) with exposures in the ‘control’ period (the previous workweek). Stratified analyses were utilised to estimate the effects of gender, ethnicity, training and the number of adjacent coworkers on each transient risk factor.

Results The authors interviewed 295 meatpacking workers with laceration injuries (mean age 36.6 years, SD 11.2, 75% men, 48% Hispanic). Recent tool sharpening (RR 5.3, 95% CI 3.8 to 7.4) and equipment malfunction (RR 5.3, 95% CI 3.9 to 7.3) were associated with the highest RR for laceration injury, followed by using an unusual work method to accomplish a task (RR 4.1, 95% CI 2.6 to 6.4) and performing an unusual task (RR 2.3, 95% CI 1.8 to 3.0). Rushing and being distracted were not significantly associated with an elevated RR of a laceration injury. In stratified analyses, there were a number of significant differences in laceration risk factors by gender, ethnicity, training, and number of workers on the line.

Conclusions Sharpening tools, equipment malfunction, using an unusual work method to accomplish a task and performing an unusual task were all associated with increased risk of lacerations. Expanded training in atypical work circumstances and evaluation of tool sharpening procedures are intervention areas in meatpacking that need examination.

  • Lacerations
  • meatpacking
  • case-crossover
  • occupational
  • traumatic injury
  • meat processing
  • epidemiology

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  • Funding This work was supported by grant R01OH008174 (NIOSH, MJP, PI).

  • Competing interests None.

  • Ethics approval Ethical approval was provided by the Institutional Review Board of the University of Nebraska–Lincoln and the Office of Human Research Administration of the Harvard School of Public Health.

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