Research to practice: Effectiveness of controlled workplace interventions to reduce musculoskeletal disorders in the manufacturing environment—critical appraisal and meta-analysis

Previous studies on the effectiveness of interventions in reducing musculoskeletal disorders (MSD) in manufacturing facilities had contradictory results, indicating a need for a quality assessment of these studies followed by a quantitative assessment of the overall effectiveness of the interventions. These assessments may also provide suggestions for practical implementations. The first objective of this study is to assess the effectiveness of controlled workplace interventions to reduce the occurrence of MSD in the manufacturing environment by utilizing meta-analysis integrated with the study quality score. The second objective is to translate the research findings into practical guidelines. Two hypotheses were tested pertinent to the first objective: (1) Controlled workplace interventions are effective in reducing the occurrence of MSD in different body regions among manufacturing workers and (2) the study quality scores do not depend on the evaluator. The study quality was assessed for all articles, however, meta effect size (meta-OR) was calculated only for the articles that reported prevalence of low back disorders (LBDs), using the MantelHaenszel method. The effect of study quality was included into meta-OR. The chi-square test of independence was employed to test the second hypothesis. Seven articles were identified. Study quality was poor (0.39 out of 2) to moderate (0.97). Insignificant reduction in LBDs prevalence (meta-OR = 0.925; 95% CI: 0.5661.512) was found. Integration of the study quality did not have a substantial effect on the meta-OR (meta-OR = 0.933; 95% CI: 0.5711.525). Each evaluator's study quality scores were not independent from the agreed quality scores (p < 0.01). The results suggested that practitioners should consider scientific evidence during design and implementation of an intervention, especially in terms of study duration, confounders, outcome measures, and data analysis. The articles reviewed exhibited the following: (1) the statistical insignificance of the meta-OR; (2) the relatively low methodological quality of studies; and (3) the small number of studies included in the meta-OR. The extent of the generalizability of meta-OR for LBD to other body regions was also in question. Future research should consider the following: (1) the physical and nonphysical work environment should be assessed to determine the workplace-specific needs, and the intervention should be structured around these needs; (2) group comparability, participation rate, subject loss, and randomization of subjects should be taken into account; (3) exposure and outcome measurement methods should be reported, as well as blinding of the observers and subjects, when applicable, to ensure reliability and validity; and (4) data analysis should be conducted adjusting for covariates and confounders, different lengths of follow-up, and level of exposure. © 2008 Wiley Periodicals, Inc.