Work-Related Musculoskeletal Disorders
What Are Musculoskeletal Disorders?
Musculoskeletal disorders include a group of conditions that involve the nerves, tendons, muscles, and supporting structures such as intervertebral discs. They represent a wide range of disorders, which can differ in severity from mild periodic symptoms to severe chronic and debilitating conditions. Examples
include carpal tunnel syndrome, tenosynovitis, tension neck syndrome, and low back pain.
What Are Work-Related Musculoskeletal Disorders (WMSDs)?
Work-Related Musculoskeletal Disorders are musculoskeletal disorders caused or made worse by the work environment.
WMSDs can cause severe and debilitating symptoms such as pain, numbness, and tingling; reduced worker productivity; lost time from work; temporary or permanent disability; inability to preform job tasks; and an increase in workers compensation costs.
Musculoskeletal disorders are often confused with ergonomics. Ergonomics is the science of fitting workplace conditions and job demands to the capabilities of workers. In other words, musculoskeletal disorders are the problem and ergonomics is a solution.
What Are the Risk Factors for WMSDs?
Repetitive, forceful, or prolonged exertions of the hands; frequent or heavy lifting, pushing, pulling, or carrying of heavy objects; prolonged awkward postures; and vibration contribute to WMSDs. Jobs or working conditions that combine risk factors will increase the risk for musculoskeletal problems.
The level of risk depends on how long a worker is exposed to these conditions, how often they are exposed, and the level of exposure.
How Common Are MSDs?
Musculoskeletal disorders of any cause are among the most prevalent medical problems, affecting 7% of the population and accounting for 14% of physician visits and 19% of hospital stays.
When looking specifically at work-related musculoskeletal disorders, the Bureau of Labor Statistics (BLS) reports that in 1995, 62% (308,000) of all illness cases were due to disorders associated with repeated trauma. This figure does not include back injuries. BLS also reports that the number of cases of repeated trauma has increased significantly, rising from 23,800 cases in 1972 to 332,000 cases in 1994—a fourteen-fold increase. In 1995 the number of cases decreased by 7% to 308,000 reported cases, but this number still exceeds the number of cases in any year prior to 1994.
When looking specifically at cases involving days away from work, for which more detailed information is available, BLS reports that in 1994, approximately 32% or 705,800 cases were the result of overexertion or repetitive motion. This figure includes back injuries.
What Can Be Done to Prevent WMSDs?
Much can be done to prevent WMSDs. Ergonomics programs to prevent WMSDs can be tailored to a particular workplace. NIOSH has developed Elements of Ergonomics Programs, a Primer based on workplace evaluations of musculoskeletal disorders which is useful in developing an ergonomics program (see below).
NIOSH Research and Prevention
NIOSH conducts and funds a substantial amount of research on musculoskeletal disorders, currently a total of 80 projects on WMSD-related topics. A directory of all these projects has been published by NIOSH (DHHS [NIOSH] Publication No. 97-109). The following are some examples of current WMSD activities at NIOSH.
Review of the Epidemiologic Literature
NIOSH scientists have completed the most comprehensive review to date of the epidemiologic literature on the relation between selected MSDs and exposure to physical factors at work. The resulting document, entitled Musculoskeletal Disorders and Workplace Factors: A Critical Review of Epidemiologic Evidence for Work-Related Musculoskeletal Disorders of the Neck, Upper Extremity, and Low Back (DHHS [NIOSH] Publication No. 97-141) examined more than 2,000 scientific studies. Based on this review, NIOSH concludes that a large body of credible epidemiologic research exists that shows a consistent relationship between MSDs and certain physical factors, especially at higher exposure levels.
Ergonomics: Effective Workplace Practices and Programs
The ergonomics conference, cosponsored by NIOSH and OSHA, provided a forum for sharing effective programs for preventing musculoskeletal disorders in the workplace. Over 1,000 participants—from labor, industry, business, universities, health care, professional societies—attended the January 1997 conference.
National Occupational Research Agenda
The National Occupational Research Agenda (NORA) is a framework to guide occupational safety and health research into the next decade. The Agenda consists of 21 priorities most likely to improve safety and health of our nation’s workforce. Two MSD-related priority areas, low back disorders and musculoskeletal disorders of the upper extremities, are included in the agenda based on unanimous support from a diverse group of stakeholders.
Evaluation of the Efficacy of Back Belts in Material Handling Workers
This study will assess the effect of back belts and other factors such as fitness, strength, and work exposure variables on back injury in 8000 material handling workers employed in a retail merchandise store chain.
Household Appliance & Intervention Study
This study will assess ergonomic factors in an appliance manufacturing facility. The objectives of this research are to evaluate the process of implementing engineering-based controls, and to assess the effect of “front-end” engineering on workers exposed to ergonomic stressors and on the incidence of work-related injury and illness.
Printing Operation Study
NIOSH is working with representatives of the printing industry to reduce musculoskeletal disorders of the lower back and upper extremities. The objective of this study is to develop low cost solutions, such as lift tables to reduce manual material handling tasks. These solutions will be videotaped and disseminated to the printing industry.
Nursing Home Back Intervention Study
This research evaluates lifting equipment and medical management programs for their effectiveness in reducing the incidence, cost, and disability associated with work-related injuries and complaints of pain.
Work Organization Interventions and Prevention of Musculoskeletal Disorders
NIOSH is examining the efficacy of various work organization interventions such as alternative work-rest schedules and task rotation in preventing stress and musculoskeletal disorders in repetitive computer work.
Additional Information
Copies of the NIOSH publications discussed in this document are available free-of-charge from the NIOSH Publications Office while supplies last (telephone 1-800-356-4674; fax 513-533-8573; e-mail pubstaft@cdc.gov). NIOSH has also prepared a bibliography on cumulative trauma disorders (CTDs) in the workplace (DHHS [NIOSH] Publication No. 95-119).
Additional information about several of the topics discussed in the preceding pages are available from the toll-free CDC Fax Information Service (1-888-232-3299). For information about carpal tunnel syndrome, request fax document # 705001; for information about the revised NIOSH lifting recommendation, request document # 705110; for information about back belts, request document
# 705004; for information about NORA, request document # 705011.
Document #705005
July, 1997
