***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Occupational low back pain ( OLBP ) is widespread in industrialized societies . We present a model to estimate the net economic costs of investments in ergonomic interventions at the company level to reduce work-related low back pain . METHODS Costs of interventions are defined by incorporating not only the costs of investment of equipment and labor , but also by taking into account the avoided costs of lost work time , medical care costs , and productivity improvements . In the net-cost model , all costs are annualized and are calculated at the level of an individual organization . Three case studies have been performed based on data from three companies in the manufacturing sector of the United States using the above approach . RESULTS The net-cost estimates for the three case studies consistently show that ergonomic interventions applied appropriately can result in substantial cost savings for the companies . CONCLUSIONS Although generalizing on the basis of three case studies is not ideal , our analyses show that it might be in the economic interest of management to play a more active role to prevent back pain . Gathering useful retrospective cost data , even on interventions deemed effective by corporate innovators , proved to be extremely difficult . We conclude that it is essential to incorporate a protocol for collecting cost and effectiveness data in the st and ard operating procedures of ergonomists and companies introducing such innovation . We intend to vali date the net-cost model for the monitoring and reporting of such data through prospect i ve studies in a variety of industrial setting s and in countries at various stages of economic development BACKGROUND High rates of work-related injuries are seen among health care workers involved in lifting and transferring patients . We studied the effects of a participatory worker-management ergonomics team among hospital orderlies . METHODS This prospect i ve intervention trial examined work injuries and other outcomes before and after the intervention , with other hospital employees used as a concurrent control . All orderlies in a 1,200-bed urban hospital were studied using passively collected data ( mean employment during study period 100 - 110 orderlies ) ; 67 orderlies ( preintervention ) and 88 orderlies ( postintervention ) also completed a question naire . The intervention was the formation of a participatory ergonomics team with three orderlies , one supervisor , and technical advisors . This team design ed and implemented changes in training and work practice s. RESULTS The 2-year postintervention period was marked by decreased risks of work injury ( RR = 0.50 , 95 % CI 0.35 - 0.72 ) , lost time injury ( RR = 0.26 , 95 % CI 0.14 - 0.48 ) , and injury with three or more days of time loss ( RR = 0.19 , 95 % CI 0.07 - 0.53 ) . Total lost days declined from 136.2 to 23.0 annually per 100 full-time worker equivalents ( FTE ) . Annual workers ' compensation costs declined from $ 237/FTE to $ 139/FTE . The proportion of workers with musculoskeletal symptoms declined and there were statistically significant improvements in job satisfaction , perceived psychosocial stressors , and social support among the orderlies . CONCLUSION Substantial improvements in health and safety were seen following implementation of a participatory ergonomics program Background : Call centre work with computers is associated with increased rates of upper body pain and musculoskeletal disorders . Methods : This one year , r and omised controlled intervention trial evaluated the effects of a wide forearm support surface and a trackball on upper body pain severity and incident musculoskeletal disorders among 182 call centre operators at a large healthcare company . Participants were r and omised to receive ( 1  ) ergonomics training only , ( 2 ) training plus a trackball , ( 3 ) training plus a forearm support , or ( 4 ) training plus a trackball and forearm support . Outcome measures were weekly pain severity scores and diagnosis of incident musculoskeletal disorder in the upper extremities or the neck/shoulder region based on physical examination performed by a physician blinded to intervention . Analyses using Cox proportional hazard models and linear regression models adjusted for demographic factors , baseline pain levels , and psychosocial job factors . Results : Post-intervention , 63 participants were diagnosed with one or more incident musculoskeletal disorders  . Hazard rate ratios showed a protective effect of the armboard for neck/shoulder disorders ( HR = 0.49 , 95 % CI 0.24 to 0.97 ) after adjusting for baseline pain levels and demographic and psychosocial factors . The armboard also significantly reduced neck/shoulder pain ( p = 0.01 ) and right upper extremity pain ( p = 0.002 ) in comparison to the control group . A return-on-investment model predicted a full return of armboard and installation costs within 10.6 months . Conclusion : Providing a large forearm support combined with ergonomic training is an effective intervention to prevent upper body musculoskeletal disorders and reduce upper body pain associated with computer work among call centre employees BACKGROUND Low back injuries are common and costly , accounting for 15 to 25 percent of injuries covered by workers ' compensation and 30 to 40 percent of the payments made under that program . The high costs of injury , the lack of effective treatment . and the evidence that there are behavioral risk factors have led to widespread use of employee education programs that teach safe lifting and h and ling . The effectiveness of those programs , however , has received little rigorous evaluation . METHODS We evaluated an educational program design ed to prevent low back injury in a r and omized , controlled trial involving about 4000 postal workers . The program , similar to that in wide use in so-called back schools , was taught by experienced physical therapists . Work units of workers and supervisors were trained in a two-session back school ( three hours of training ) , followed by three to four reinforcement sessions over the succeeding few years . Injured subjects ( from both the intervention and the control groups ) were r and omized a second time to receive either training or no training after their return to work . RESULTS Physical therapists trained 2534 postal workers and 134 supervisors . Over 5.5 years of follow-up , 360 workers reported low back injuries , for a rate of 21.2 injuries per 1000 worker-years of risk . The median time off from work per injury was 14 days ( range , 0 to 1717 ) ; the median cost was $ 204 ( range , zero to $ 190,380 ) . After their return to work , 75 workers were injured again . Our comparison of the intervention and control groups found that the education program did not reduce the rate of low back injury , the median cost per injury , the time off from work per injury , the rate of related musculoskeletal injuries , or the rate of repeated injury after return to work ; only the subjects ' knowledge of safe behavior was increased by the training . CONCLUSIONS A large-scale , r and omized , controlled trial of an educational program to prevent work-associated low back injury found no long-term benefits associated with training To define the cost-effectiveness of a back school program in industry , a controlled longitudinal field study was carried out in a Dutch bus company . The experimental group received a program consisting of information on back care , physical fitness , nutrition , stress , and relaxation . Objective data on absenteeism were collected and compared during a 6-year period for the control and experimental groups . Results showed that a tailor-made back school program reduced absenteeism by at least 5 days per year per employee , therefore being cost-effective to industry . A reduction was not observed in incidence , but in mean length of absenteeism . This effect turned out to be persistent during a 2-year period following the program 
    Output:
    
Results In the manufacturing and warehousing sector strong evidence was found in support of the financial merits of ergonomic interventions  from a firm perspective .
In the administrative support and health care sectors moderate evidence was found , in the transportation sector limited evidence , and in remaining sectors insufficient evidence .
Conclusions Most intervention studies focus on effectiveness .
Few consider their financial merits .
Often only a small part of the overall evaluation of many studies focused on evaluating their cost-effectiveness