An epidemiological prospective cohort study of the ability of the 1991 NIOSH Lifting Equation to predict loss of time from work due to low back pain (LBP) or to predict reports of LBP followed 515 industrial workers in jobs requiring manual handling for 18 months. Baseline measurements were made of their jobs, histories of musculoskeletal trouble and of psychosocial variables. Longitudinal analysis of tasks was based on 367 subject/job combinations.
The strongest predictor of future LBP was a history of LBP. No relationship was found between the Composite Lifting Index (CLI) and either the incidence of lost time due to LBP or the prevalence of LBP (adjusted Hazard Ratio (HR) = 1.0, 95% Confidence Interval (CI) 0.9 - 1.1). The CLI is not useful as a method for assessing risk of LBP due to manual handling.
The maximum value of the Single Task Lifting Index (STLI) gave an adjusted HR of 1.1 (95% CI 0.9 - 1.4). It too is not useful as a method for assessing risk of LBP due to manual handling.
There is a need to develop better methods of assessing risk of LBP from manual handling, focusing on ways of combining risk factors and exposure to multiple tasks.
This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.
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