Document Detail

Physical workload, ergonomic problems, and incidence of low back injury: a 7.5-year prospective study of San Francisco transit operators.
MedLine Citation:
PMID:  15551390     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The etiologic role of biomechanical factors for low back injury (LBI) needs to be confirmed in prospective studies that control for psychosocial factors. METHODS: Complete baseline information on 1,233 vehicle operators was gathered during medical examinations and by questionnaire. First LBI during 7.5 years of follow-up was ascertained from insurance records. Hazard ratios and etiologic fractions were analyzed with Cox regression models stratified by injury severity and controlling for age, sex, height, weight, ethnicity, and biomechanical and psychosocial job factors. Severe LBI was defined as medically diagnosed postlaminectomy syndrome, spinal stenosis, herniated lumbar disc, sciatica, or spinal instability. RESULTS: An exponential dose-response relationship was found between weekly driving hours and incidence of first LBI. Indicators of physical workload were more strongly associated with more severe low back injuries compared to less severe injuries. Rates of severe LBI increased 39% for every 10-hr increase in weekly driving (hazard ratio 1.39, 95% confidence interval 1.15-1.68). Higher risks of severe LBI were also found among operators performing heavy physical labor on cable cars (hazard ratio 2.76, 95% confidence intervals 1.24-6.14) or reporting more ergonomic problems at baseline (HR for upper quartile 1.65 (95% confidence interval 1.08-2.50). Estimates of etiologic fractions suggest that reduction of ergonomic problems to the low level currently experienced by 25% of drivers would result in a 19% reduction of severe LBI among all drivers. A change from full- (more than 30 hr) to part-time driving (20-30 hr) could reduce the number of severe LBI by 59%, although this gain would be reduced to 28% at the company level if injuries expected among additional employees, hired to maintain full service are included. CONCLUSIONS: Duration of professional driving and ergonomic problems are independent and preventable risk factors for LBI even after adjustment for psychosocial factors.
Niklas Krause; Reiner Rugulies; David R Ragland; S Leonard Syme
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of industrial medicine     Volume:  46     ISSN:  0271-3586     ISO Abbreviation:  Am. J. Ind. Med.     Publication Date:  2004 Dec 
Date Detail:
Created Date:  2004-11-24     Completed Date:  2005-03-10     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8101110     Medline TA:  Am J Ind Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  570-85     Citation Subset:  IM    
Department of Medicine, University of California, San Francisco, CA 94804, USA.
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MeSH Terms
Age Distribution
Automobile Driving*
Back Injuries / diagnosis,  epidemiology*
Cohort Studies
Human Engineering*
Injury Severity Score
Low Back Pain / epidemiology,  etiology
Middle Aged
Multivariate Analysis
Occupational Diseases / diagnosis,  epidemiology*
Occupational Health*
Predictive Value of Tests
Prospective Studies
Risk Factors
San Francisco / epidemiology
Sex Distribution
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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