The National Academy of Sciences and the Institute of Medicine recently released their long-awaited report on Musculoskeletal Disorders and the Workplace. The report, requested by industry groups and conservative Republicans who opposed an OSHA ergonomics standard, finds that there is strong scientific evidence showing that exposure to ergonomic hazards in the workplace causes musculoskeletal disorders and that these injuries can be prevented. Prepared by some of the world's top scientific and medical experts in ergonomics, the report calls MSDs an important national problem and strongly supports the approach that OSHA took in its now-defunct Ergonomics Program Standard.

This is the third comprehensive review of the scientific literature in the past four years that has come to the same conclusions. The National Institute for Occupational Safety and Health (NIOSH) published a comprehensive review of the data on the relationship between MSDs and the workplace in 1997. The NAS also came to similar conclusion in an earlier report published in 1998.

The NAS report puts to rest, once and for all, the claims by some industry groups and conservative Republicans that there is no scientific evidence that workplace exposures cause musculoskeletal disorders. It shows without question that an OSHA ergonomics standard is needed and justified.

Musculoskeletal Disorders Are an Important National Health Problem

The NAS report confirms OSHA's estimates of the scope of the problem, citing an even larger number of workers losing time from work than OSHA. The NAS estimates that 1 million people lose time from work each year due to these disabling injuries, compared with OSHA's more conservative estimate of 600,000. The NAS also confirms OSHA's estimate that ergonomic problems cost the economy around $50 billion each year. The report warns that MSD-related problems are expected to increase in the future due to the changing nature of work, the aging of the workforce and rising numbers of women entering material handling and computer jobs.

The report also finds that existing national data sources conclude that construction and agricultural workers, who were not covered in the OSHA standard, also suffer higher rates of work-related MSDs than overall industry.

"There is no doubt that musculoskeletal disorders of the low back and upper extremities are an important and costly national health problem...In 1999, nearly 1 million people took time away from work to treat and recover from work-related musculoskeletal pain or impairment of function in the low back or upper extremities. Conservative estimates of the economic burden imposed, as measured by compensation costs, lost wages, and lost productivity, are between $45 and $54 billion annually" (page ES-1).

"The consequences of musculoskeletal disorders to individuals and society and the evidence that these disorders are to some degree preventable justify a broad, coherent effort to encourage the institution or extension of ergonomic and other preventive strategies" (page ES-6).

"As the workforce ages and as more women enter the workforce, particularly in material handling and computer jobs, evaluation of work tasks, especially lifting, lowering, carrying, prolonged static posture, and repetitive motion, will be required to guide the further design of appropriate interventions" (page 11-2).

Science Strongly Supports the Fact That There Is a Strong Relationship Between Workplace Physical Tasks and the Risk of MSDs

The NAS found a strong and consistent pattern of evidence from both epidemiologic studies (studies of groups of people experiencing similar exposures), as well as "biomechanical" evidence (the actual damage that ergonomic stress does to muscles, tendons and nerves.) The report cites the same workplace risk factors that OSHA addressed in its standard heavy lifting, repetition, force, frequent bending and twisting (awkward postures) and vibration. The report actually goes beyond the 2000 OSHA standard, including whole body vibration as a risk factor for back injuries, where OSHA only regulated hand-arm vibration.

While more research and better quality studies are clearly desirable, the NAS report finds that the consistent overall pattern of evidence from existing studies clearly confirms the relationship between workplace physical exposures and MSDs.

"The basic biology and biomechanics literatures provide evidence of plausible mechanisms for the association between musculoskeletal disorders and workplace physical exposures" (page ES-6).

"The panel's review of the research literature in epidemiology, biomechanics, tissue mechanobiology, and workplace intervention strategies has identified a rich and consistent pattern of evidence that supports a relationship between the workplace and the occurrence of MSDs of the low back and upper extremities" (page ES-3).

"The panel concludes that there is a clear relationship between back disorders and physical load; that is, manual material handling, load movement, frequent bending and twisting, heavy physical work, and whole-body vibration. For disorders of the upper extremities, repetition, force and vibration are particularly important work-related factors" (page 11-10).

"Occupations that involve repetitive lifting, e.g., warehouse work, construction and pipe fitting, particularly when that activity involves twisting postures, are associated with an increased risk for the complaint of low back pain and, in a few studies, an increased risk for lumbar disc herniation" (App. A-6).

"Low back disorder risk has been established through epidemiologic studies of work that involves heavy lifting, frequent bending and twisting and whole body vibration, as well as other risk factors....Biomechanical studies reinforce the epidemiologic findings" (page ES-3).

"The pattern of evidence for upper extremity disorders, as for the low back, also supports an important role for physical factors, particularly repetition, force and vibration. The most dramatic physical exposures occur in manufacturing, food processing, lumber, transportation and other heavy industries, and these industries have the highest rates of upper extremity disorder reported as work related." (page ES-4).

"There is strong support across these bodies of work that high force and repetition are associated with musculoskeletal disorder of the upper extremities; basic biology data provide evidence of alteration in tissue structure" (page ES-4).

"These exposure-response associations persist when adjusted for individual factors that may increase vulnerability, such as age, gender and body mass index" (page ES-4).

"The BLS and workers' compensation data are sufficient to (1) confirm that the magnitude of the work-related musculoskeletal disorder problem is very large; (2) demonstrate that rates differ substantially between industries and occupations consistent with the assumption that work related risks are important predictors of musculoskeletal disorders" (page 2-17).

Science Strongly Supports the Fact That Workplace Interventions Based on Ergonomic Principles Can Reduce the Risk of MSDs

The report also confirms the fact that using ergonomic principles to reduce exposure to risk factors reduces the risk of MSDs. Changing the design of tools and workstations, rotating jobs and other ergonomics interventions such as lift tables and vibration dampening seating devices that reduce ergonomic risk factors have been shown to reduce the risk of MSDs of the low back and upper extremities.

"The weight of the evidence justifies the introduction of appropriate and selected interventions to reduce the risk of musculoskeletal disorders of the low back and upper extremities" (page 11-2).

"The intervention literature supports the efficacy of tool and workstation design changes, job rotation, and other interventions that directly address these risk factors with regard to upper extremity symptomology" (page ES-4).

"Intervention studies have shown how lift tables and lifting hoists are effective in mediating the risk of low back pain in industrial settings. Since risk is lowered when the load is changed from a heavy lift to a light lift, this finding is also consistent with the rigorous epidemiologic finding" (page ES-3).

"Based on the current evidence, modification of the lifting can reduce symptoms and complaints. Specific successful strategies, which include ergonomic interventions (such as the use of lift tables and other devices and matching the worker's capacity to the lifting tasks), administrative controls (such as job rotation), and team lifting, appear successful. Despite enthusiasm for their use, there is marginal or conflict evidence about lifting belts and education programs in reducing low back pain in the population with heavy lifting requirements" (page App. A).

The NAS Report Supports the Main Elements Included in the OSHA Standard

The NAS Report found that employers with effective ergonomics programs use a programmatic approach that OSHA had adopted in its since repealed ergonomics standard of November 2000. The OSHA standard required employers to include several basic program elements in approaching ergonomic problems: Management Leadership and Employee Participation, Job Hazard Analysis and Control, Training, Medical Management and Program Evaluation. These are the same common elements that the NAS report found in successful ergonomics programs. This programmatic approach provides a framework for employers; it does not dictate how employers are to address the problems. This approach allows and anticipates that employers will tailor their programs to meet the own specific needs of their workplace and work organization. The NAS report found this approach to be effective in small and large companies from a variety of industries.

"To be effective, intervention programs should include employee involvement, employer commitment and the development of integrated programs that address equipment design work procedures and organizational characteristics" (page ES-6 and 11-2).

"The complexity of musculoskeletal disorders in the workplace requires a variety of strategies that may involve the worker, the workforce and management. These strategies fall within the categories of engineering controls, administrative controls and worker-focused modifiers. The literature shows that no single strategy is or will be effective for all types of industry; interventions are best tailored to the individual situation. However, there are some program elements that consistent recur in successful programs:

"These findings are based on a research and development process that tailors interventions to specific work and workers conditions and evaluates, on a continuing basis, the effectiveness of these interventions in the face of changing workplace and worker factors. It is therefore neither feasible nor desirable to propose a generic solution" (page ES-5).