Evaluation of the revised NIOSH lifting equation: a cross sectional epidemiological study.
Waters-T; Baron-S; Haring-Sweeney-M; Piacitelli-L; Putz-Anderson-V; Wall-D; Skov-T; Fine-L
From Experience to Innovation. IEA'97, Vol. 3, Complex Systems, Cognitive Ergonomics, Occupational Safety, Materials Handling, Proceedings of the 13th Triennial Congress of the International Ergonomics Association, Tampere, Finland, June 29-July 4, 1997. Seppala P, Luopajarvi T, Nygard H, Mattila M, eds. Helsinki, Finland: Finnish Institute of Occupational Health, 1997 Jun; 3:583-585
The results of an epidemiological study designed to evaluate the effectiveness of the revised NIOSH lifting equation (NLE) for predicting the risk of low back pain (LBP) due to manual lifting were summarized. The purpose of the study was to test the hypothesis that lifting tasks that had a lifting index (LI) of 1.0, as calculated from the NLE, could present an increased risk for LBP. Fifty lifting jobs were evaluated. A total of 204 workers performing the lifting jobs and 80 persons not involved in manual lifting completed a questionnaire to report LBP for at least 1 week during the past 12 months and to score potential personal and psychosocial confounders. The LI was determined for each job. Associations between self reported LBP and the LI in five categories, LI = 0 (unexposed) and LI = 0 to 1, 1 to 2, 2 to 3, and 3 or greater, were examined by logistic regression techniques. Increasing LI was significantly associated with an increasing probability of reporting LBP that lasted at least 1 week during the preceding year. The strongest association was found for LIs of between 2 and 3, odds ratio (OR) and prevalence proportion ratios (PPRS) = 2.45 and 1.90, respectively. The OR and PPR for the LI greater than 3 category were lower, being 1.63 and 1.45, respectively. Of the potential personal or psychosocial confounders, only job dissatisfaction was significantly associated with the LI or LBP, ORs as high as 6.9 being obtained for the 'not all satisfied' category of job satisfaction. The authors conclude that the risk of LBP increases as the LI increases with a peak occurring for LIs between 2 and 3. Since it is impossible to determine whether high physical stress, as indicated by a high LI, causes job dissatisfaction or whether job dissatisfaction increases the rate of reporting LBP, a model that excludes job satisfaction as a confounder is more appropriate for a cross sectional study like this, since job dissatisfaction is likely to be caused by LBP, the study outcome.
Manual-lifting; Mathematical-models; Back-injuries; Epidemiology; Work-analysis; Questionnaires; Risk-analysis; Musculoskeletal-system-disorders; Industrial-safety; Psychophysiology;
Seppala-P; Luopajarvi-T; Nygard-C-H; Mattila-M
From Experience to Innovation. IEA'97, Vol. 3, Complex Systems, Cognitive Ergonomics, Occupational Safety, Materials Handling, Proceedings of the 13th Triennial Congress of the International Ergonomics Association, Tampere, Finland, June 29-July 4, 1997