Causal assessment of workplace manual handling or assisting patients and low back pain: results of a systematic review

Roffey, Darren M.; Wai, Eugene K.; Bishop, Paul; Kwon, Brian K.; Dagenais, Simon

doi:10.1016/j.spinee.2010.04.028

« Previous Next »The Spine Journal
Volume 10, Issue 7 , Pages 639-651, July 2010

Causal assessment of workplace manual handling or assisting patients and low back pain: results of a systematic review

Darren M. Roffey, PhD
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
Eugene K. Wai, MD, MSc, FRCSC
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Division of Orthopaedic Surgery, Department of Surgery, University of Ottawa, The Ottawa Hospital, Ottawa, ON, Canada
- Corresponding author. Division of Orthopaedic Surgery, Department of Surgery, University of Ottawa, The Ottawa Hospital, 1053 Carling Ave., Ottawa, ON, K1Y 4E9, Canada. Tel.: (613) 798-5555 ext 19138; fax: (613) 761-4944.
Paul Bishop, DC, MD, PhD
- Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada
- UBC Combined Neurosurgical and Orthopaedic Spine Program, Vancouver, BC, Canada
- Vancouver Hospital Spine Program and Acute Spinal Cord Injury Unit, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
Brian K. Kwon, MD, PhD, FRCSC
- UBC Combined Neurosurgical and Orthopaedic Spine Program, Vancouver, BC, Canada
- Vancouver Hospital Spine Program and Acute Spinal Cord Injury Unit, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
Simon Dagenais, DC, PhD
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Division of Orthopaedic Surgery, Department of Surgery, University of Ottawa, The Ottawa Hospital, Ottawa, ON, Canada
- Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, ON, Canada

Received 23 December 2009; received in revised form 24 February 2010; accepted 14 April 2010. published online 31 May 2010.

Abstract

Background Context

Low back pain (LBP) is a common musculoskeletal disorder associated with a considerable social and economic burden within the working-age population. Despite an unclear etiology, numerous physical activities are suspected of leading to LBP. Declaring a causal relationship between occupational activities and LBP remains challenging and requires a methodologically rigorous approach.

Purpose

To conduct a systematic review focused on assessing the potentially causal relationship between workplace manual handling or assisting patients and LBP.

Study Design

Systematic review of the literature.

Samples

Studies reporting an association between workplace manual handling or assisting patients and LBP.

Outcome Measures

Numerical association between different levels of exposure to manual handling or assisting patients, and the presence or severity of LBP.

Methods

A systematic review was conducted using Medline, EMBASE, CINAHL, Cochrane Library, and Occupational Safety and Health database, gray literature, hand-searching occupational health journals, reference lists of included studies, and content experts. The methodological quality of each study was assessed using a modified Newcastle-Ottawa Scale (NOS) for observational studies. The overall level of evidence supporting various Bradford-Hill criteria for causality for each category of manual handling or assisting patients and type of LBP was then evaluated. Studies were deemed of higher quality if they received a score of five or more on the modified NOS and used appropriate statistical analysis methods.

Results

This search yielded 2,766 citations, and 32 studies met the eligibility criteria. Three high-quality studies reported on manual handling and LBP, including two prospective cohorts and one cross-sectional design. None demonstrated a significant association in most of their multivariate risk estimates. One study was able to assess dose-response and temporality, but its results did not support these criteria. Only one study discussed the biological plausibility of this association. Four high-quality studies evaluated assisting patients and LBP, including two case-controls, one cross-sectional, and one prospective cohort design. These studies were consistent in reporting no significant association. Two studies demonstrated a nonsignificant dose-response trend, and two studies discussed the biological plausibility of this association. No studies were able to demonstrate the temporality or experiment criteria.

Conclusions

The studies reviewed did not support a causal association between workplace manual handling or assisting patients and LBP in a Bradford-Hill framework. Conflicting evidence in specific subcategories of assisting patients was identified, suggesting that tasks such as assisting patients with ambulation may possibly contribute to LBP. It appears unlikely that workplace manual handling or assisting patients is independently causative of LBP in the populations of workers studied.

Keywords: Occupational health, Low back pain, Manual handling, Assisting patients, Causality, Etiology, Systematic review