Physical workload, ergonomic problems, and incidence of low back injury: A 7.5‐year prospective study of San Francisco transit operators

Abstract

TitlePhysical workload, ergonomic problems, and incidence of low back injury: A 7. Physical workload, ergonomic problems, and incidence of low back injury: A 7.5-year prospective study of San Francisco transit operatorsThe 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 1.24-614) 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

Physical activity and low back pain: a systematic review of recent literature

“…The occurrence of new episodes of LBP was measured by the use of questionnaires [22, 24, 25, 27, 28, 31-34, 36, 38, 39, 42, 49, 53-56], interviews [24,41,49] or reports by care providers [50][51][52]57]. Sick leave was derived from questionnaires [25,26,28,29,33,37,38,43,45,47], company registers [23,26,35,40] and social insurance administrations [30,40,48].…”

“…standing, awkward positions such as flexed-twisted-rotated), magnitudes of work and non-work-related physical loadings (light, moderate, heavy), sports and physical exercise. The measurement of the outcome (dependent) variable varied between the occurrence of new episodes of LBP [22-24, 27, 31, 32, 34, 36, 39, 41, 44, 46, 50, 52, 54, 57], sick leave due to LBP [23,26,29,30,35,40,43,48] or a combination of both [25, 28, 33, 36, 38, 42, 44-46, 49, 51, 53, 55]. Twentyeight studies applied (self-administered) questionnaires in the screening of exposures [22-24, 26-33, 36, 37, 39, 40, 42-45, 47-49, 52-57].…”

“…Associations with LBP complaints varied between moderate values (1.6: 1.14-2.3) [28] and strong values (6.2: 1.7-23.2) [45]. The exposure to vehicle driving was explored in both a working population [40] and a population-based cohort [57]. A higher amount of total driving hours was strongly associated with LBP in transit vehicle operators (2.17: 1.28-3.68) [40] and in women (2.8: 1.0-8.5) [57].…”

“…The exposure to vehicle driving was explored in both a working population [40] and a population-based cohort [57]. A higher amount of total driving hours was strongly associated with LBP in transit vehicle operators (2.17: 1.28-3.68) [40] and in women (2.8: 1.0-8.5) [57]. According to these results, there is strong evidence that the performance of occupational tasks, such as manual handling of materials, physical exertion in nursing and the exposure to vehicle driving are moderately to strongly associated with LBP.…”

Effort–reward imbalance and one-year change in neck–shoulder and upper extremity pain among call center computer operators

“…A review that analyzed 19 studies on psychosocial workplace factors and neck-shoulder symptoms concluded that "this relationship is neither very strong nor very specific" (6, p 290). The two reviews criticized that many studies have not sufficiently controlled for exposure to high physical workload and ergonomic problems (7,8). Finally, it is notable, that many studies defined psychosocial working conditions based on the demand-control (job strain) model (9) or its expansion, the demand-control-support model (10), and that there is a lack of research on alternative theoretical models of psychosocial workplace stressors.…”