National Occupational Research Agenda

Disease and Injury

Eight of the 21 priority research areas are grouped in the category of adverse health effects--namely, disease and injury. An earlier effort by NIOSH in the 1980s identified the "top ten" leading workplace diseases and injuries. In the development of NORA, participants recognized the need to include a list of diseases and injuries (albeit updated and more focused than the "top ten") and to include research areas grouped into two other broad categories: work environment and workforce, and research tools and approaches.

Early in the process, many disease and injury topics were offered for potential inclusion in NORA. Obviously, a list of significant workplace diseases and injuries could easily be many times the size of the list presented in the Agenda. Working groups performed the difficult task of refining and prioritizing to achieve this list of eight topics--topics for which concerted research efforts have the potential to improve the well-being of large numbers of workers and their families. Indeed, significant advances in the prevention of diseases or injuries encompassed by these eight areas would improve the health of millions of U.S. workers and save billions of dollars in costs related to medical treatment and lost productivity.

Allergic and Irritant Dermatitis

Allergic and irritant dermatitis (contact dermatitis) is overwhelmingly the most important cause of occupational skin diseases, which account for 15% to 20% of all reported occupational diseases. There is virtually no occupation or industry without potential exposure to the many diverse agents that cause allergic and irritant dermatitis. Research is needed to better identify the prevalence, causes, exposure assessment methods, and early biologic markers of this ubiquitous condition.

Importance

In the workplace, the skin is an important route of exposure to chemicals and other contaminants. According to the U.S. Bureau of Labor Statistics, occupational skin diseases--mostly in the form of allergic and irritant (contact) dermatitis--are the second most common type of occupational disease. From 1983 to 1994, the rate of occupational skin diseases increased from 64 to 81 cases per 100,000 workers. In 1994, there were approximately 66,000 reported cases of occupational skin diseases, accounting for about 13% of all occupational diseases. Moreover, occupational skin diseases are believed to be severely underreported, such that the true rate of new cases may be many fold higher than documented. These data stress that the national objective for reducing the rate of new cases of occupational skin diseases to 55 per 100,000 workers (as set by Healthy People 2000 ) is far from being met.

Estimated total annual costs (including lost workdays and loss of productivity associated with occupational skin diseases) may reach $1 billion annually. Workers' compensation claims rates for occupational skin diseases vary by State and range from 12 to 108 per 100,000 workers per year. Self-reported occupational dermatitis prevalence in the 1988 National Health Interview Survey was nearly 2% (1,700 cases per 100,000 workers).

Irritant contact dermatitis is the most common occupational skin disease, usually resulting from toxic reactions to chemical irritants such as solvents and cutting fluids. Allergic dermatitis is estimated to constitute about 20% to 25% of all contact dermatitis; it is caused by a wide variety of substances such as latex and some pesticides that trigger an allergic (delayed hypersensitivity) reaction. Contact urticaria (hives occurring soon after an allergen or irritant contacts the skin) is considered here also because it may evolve into contact dermatitis. A number of substances may cause both irritant and allergic dermatitis as well as contact urticaria. For example, latex (which has been reported to cause skin disorders in up to 10% of exposed health care workers), most commonly causes irritant dermatitis but it also results in allergic contact dermatitis and, least commonly, contact urticaria.

Because the prognosis of occupational irritant and allergic dermatitis is poor, prevention is imperative. This fact is emphasized by one study showing that 75% of patients with occupational contact dermatitis developed chronic skin disease. With thousands of potentially harmful chemicals being introduced into the workplace each year, and with the threat of rapidly emerging skin diseases such as latex allergy, further research of irritant and allergic contact dermatitis is greatly needed.

Research Opportunities

Just as the plight of news reporters with carpal tunnel syndrome captured public attention, disability occurring among nurses and other health care workers allergic to latex is now capturing the attention of health scientists. There has been relatively little occupational research to evaluate causes of occupational dermatitis, identify high risk occupations, develop interventions to protect workers, or assist workers who have developed skin diseases that commonly afflict them for the rest of their lives. Despite a high rate of dermatitis among agricultural workers and high numbers of cases in manufacturing, there is little research to identify and target the most important causes. Also needed are new laboratory in vitro skin models, improved statistical models for pharmacokinetic testing in animals, and improved field methods to measure permeation of skin by individual substances and mixtures. The lack of adequate tools prevents the next step in research which aims to eliminate contact with irritants and allergens by substituting safe materials for hazardous ones or by redesigning processes or materials to prevent hazardous exposures. When elimination of causative agents is economically or technically infeasible, work safety and health programs must consider the use of protective clothing and "barrier creams." However, there is insufficient substance-specific research evaluating the effectiveness of different glove and other clothing materials--particularly research involving actual work conditions and the related issues of fit, comfort, durability, multiple chemicals, and other environmental conditions. The effectiveness and utility of barrier creams are largely unexamined. Moreover, there is almost no research to identify major causes for improper use of protective clothing and to target specific populations requiring improved education about appropriate use. Research also needs to provide protection and treatment for workers who have special susceptibility or who have already developed a chronic occupational skin disease.

Asthma and Chronic Obstructive Pulmonary Disease

Occupationally-related airway diseases, including asthma and chronic obstructive pulmonary disease (COPD), have emerged as having substantial public health importance. Nearly 30% of COPD and adult asthma may be attributable to occupational exposure. Occupational asthma is now the most frequent occupational respiratory disease diagnosis. More than 20 million U.S. workers are exposed to substances that can cause airway diseases. Research is needed to clarify the prevalence, risk factors, and exposure-disease relationships, to refine techniques for monitoring worker health and the job environment, and to develop effective and practical means for preventing work-related airway diseases in at-risk workers.

Importance

Asthma and chronic obstructive pulmonary disease (COPD--primarily chronic bronchitis and emphysema) are diseases of the lung airways. More than 20 million workers are potentially exposed to occupational agents capable of causing these diseases-- including nearly 9 million workers occupationally exposed to known sensitizers and irritants associated with asthma. Occupational asthma is now the most frequent occupational respiratory disease diagnosis among patients visiting occupational medicine clinics.

Asthma and COPD accounted for nearly 18 million physician visits in 1985 and an estimated 800,000 hospital admissions in 1987. In 1992, asthma and COPD caused nearly 92,000 deaths in the United States, making airway diseases the fourth leading cause of death overall. Mortality from asthma and COPD is increasing annually. Estimated yearly costs for occupational asthma are approximately $400 million.

Asthma currently affects more than 10 million individuals in the United States and is increasing in prevalence. Recent evidence suggests that as many as 28% of adult asthma cases may be attributable to work settings. In addition to those who develop occupational asthma as a result of workplace exposure to sensitizers or irritants, many workers are unaware that pre-existing asthma may be worsened by the work environment. Each year the number of asthma cases is increasing, and major new problem areas are emerging. For example, as a result of increased use of protective gloves (which is due to the introduction of universal precautions and the OSHA regulations on bloodborne pathogens), latex allergies have become a major problem for health care workers. A significant number of these workers (2.5% in one study) have developed latex-related asthma. Morbidity from occupational asthma is preventable. Early diagnosis holds substantial promise for effective intervention. Complete resolution of symptoms and pulmonary function abnormalities is most likely when an affected individual's exposure is terminated early in the course of the illness; so early diagnosis holds substantial promise for effective intervention.

The relationship of COPD to workplace exposures is also well documented in studies of several occupational agents (e.g., coal dust, grain dust, and cotton dust). Investigations of the health consequences of particulate exposure in the general environment--where exposures are at a far lower level than in the workplace--also suggest that COPD resulting from generally dusty conditions may be an important cause of preventable disease and death. Those with lung disease from other causes are especially vulnerable to occupational respiratory hazards. Although cigarettes remain the primary cause of pulmonary diseases in the United States, many occupational and environmental exposures (both by themselves or in combination with smoking) are known to cause COPD. One estimate of the proportion of COPD attributable to occupational exposure in the general population is 14%.

Research Opportunities

Disabling effects of asthma and COPD may in many cases drive a person out of a line of work or out of work completely. The machinist who becomes asthmatic from breathing droplets of cutting fluids and the nurse allergic to latex may have to relinquish their skilled professions. An agricultural worker with an obstructive lung disease may become unemployable. These personal effects have serious business consequences beyond issues of medical costs and workers' compensation. Employee turnover in highly skilled professions is especially costly. Scientists associating dust exposures in specific work operations with high levels of COPD can test alternative approaches to dust suppression, evaluate the impact of providing workers with respirators, and determine the benefit of medical screening in reducing disease effects. There has been little research to evaluate the potential impact of occupational risk information on smoking among workers at risk. Research that investigates how workers become sensitized to substances causing asthma, (e.g., such as latex) may enable employers to screen for biomarkers or other early indications of risk before workers become disabled; such studies may also enable researchers to develop methods to replace or control exposures to the sensitizing agent. Development of tests to identify substances and processes that may cause asthma would have enormous benefits, enabling health scientists to work with product designers to assure the safety of new materials before they are introduced to the workplace, preventing disease before any cases occur, and avoiding the need for employers to implement additional prevention programs.

Fertility and Pregnancy Abnormalities

While more than 1,000 workplace chemicals have shown reproductive effects in animals, most have not been studied in humans. In addition, most of the 4 million other chemical mixtures in commercial use remain untested. Physical and biological agents in the workplace that may affect fertility and pregnancy outcomes are practically unstudied. The inadequacy of current knowledge coupled with the ever-growing variety of workplace exposures pose a potentially serious public health problem. Over the next 10 years, research priorities should include expanding surveillance systems, studying working populations thought to be at risk, increasing the understanding of fundamental biological processes underlying normal and abnormal reproductive function or outcomes, and enhancing methods to identify hazards before placing human populations at risk.

Importance

Disorders of reproduction include birth defects, developmental disorders, spontaneous abortion, low birth weight, preterm birth, and various other disorders affecting offspring; they also include reduced fertility, impotence, and menstrual disorders. Infertility is currently estimated to affect more than 2 million U.S. couples (one in 12 couples find themselves unable to conceive after 1 year of unprotected intercourse). Though not all infertile couples seek treatment, it is estimated that about $1 billion was spent in 1987 on health care related to infertility. In 1991, physician visits for infertility services numbered 1.7 million. Although numerous occupational exposures have been demonstrated to impair fertility (e.g., lead, some pesticides, and solvents), the overall contribution of occupational exposures to male and female infertility is unknown. Moreover, observed global trends in men's decreasing sperm counts have elevated concerns about the role of chemicals encountered at work and in the environment at large.

Birth defects are the leading cause of infant mortality in the United States, accounting for 20% of infant deaths (more than 8,000) each year. Every year about 120,000 babies are born in the United States with a major birth defect--about 3 per 100 live births. The 1992 costs for 17 of the most clinically important structural birth defects and for cerebral palsy were estimated to be about $8 billion. Neural tube defects (which include spina bifida and anencephaly), affect 4,000 pregnancies each year, with each new case of spina bifida having a discounted lifetime cost of $294,000 (1992 dollars). Seventeen percent of all children in the United States have some type of developmental disability. The major developmental disabilities of mental retardation, cerebral palsy, hearing impairment, and vision impairment affect about 2% of all school-age children.

Most birth defects and developmental disabilities are of unknown cause. The overall contribution of workplace exposures to reproductive disorders and congenital abnormalities is not known. Although some specific reproductive hazards have been identified in humans (e.g., lead, solvents, and ionizing radiation), most of the more than 1,000 workplace chemicals that have shown abnormal reproductive effects in animals have not been studied in humans. In addition, most of the 4 million other chemical mixtures in commercial use remain untested. Substances and activities that upset the normal hormonal activity of the reproductive system--such as shift work or pesticides that possess estrogenic activity--also need evaluation. Similarly, the effects of physical factors (such as prolonged standing, reaching, or lifting) or the interactive effects of workplace stressors and exposures on pregnancy and fertility have not been rigorously investigated.

Although the total number of workers potentially exposed to reproductive hazards is difficult to estimate, three-quarters of employed women and an even greater proportion of employed men are of reproductive age. More than half of U.S. children are born to working mothers. The vast number of workers of reproductive age together with the substantial number of workplace chemical, physical, and biological agents suggest that a considerable number of workers are potentially at risk for adverse reproductive outcomes.

Although the causes of reproductive disorders and adverse pregnancy outcomes are poorly defined, lost productivity and deep suffering by affected individuals and families are evident. The contribution that may be made by occupational factors is largely unexplored, since the reproductive health of workers has only recently emerged as a serious focus of scientific investigation. Identifying reproductive hazards in the workplace has the potential for significantly reducing the multibillion-dollar costs and alleviating the personal suffering associated with disorders of reproduction.

Research Opportunities

Substantial research is required to advance from the current high level of concern about the role of the workplace to a broad understanding of the most important hazards, their impacts, and prevention. That research must span the entire range of human clinical research, surveillance, and targeted field investigations of populations at risk. These studies could serve to identify preventable effects in workers or their offspring, such as field studies like those that detected reduced semen quality in men occupationally exposed to glycol ethers, or increased spontaneous abortions in semiconductor workers. Research may also serve to allay fears and avert unnecessary expense, for example, epidemiologic studies such as the sentinel one which showed that working with computer screens is not associated with miscarriage. Research is needed spanning the entire range of laboratory investigation from basic biology to the development and application of techniques to detect potentially hazardous conditions or agents. For example, improved understanding of basic biology (such as the actions of hormonal disrupters) will enhance prevention of reproductive disorders. Success on these fronts will allow reproductive hazards in the workplace to be recognized and removed; it will allow new or emerging hazards to be identified before large numbers of workers are placed at risk; and it could allow significant reductions in the currently heavy social, economic, and personal burdens imposed by reproductive disorders.

Hearing Loss

Occupational hearing loss may result from an acute traumatic injury, but it is far more likely to develop gradually as a result of chronic exposure to ototraumatic (damaging to the ear or hearing process) agents. Noise is the most important occupational cause of hearing loss, but solvents, metals, asphyxiants, and heat may also play a role. Exposure to noise combined with other agents can result in hearing losses greater than those resulting from exposure to noise or other agents alone. Research is needed to define further the causal contributions of these hazards (alone or in combination) and to implement and evaluate methods for early detection and hearing conservation programs.

Importance

Occupational hearing loss is the most common occupational disease in the United States: it is so common that it is often accepted as a normal consequence of employment. More than 30 million workers are exposed to hazardous noise, and an additional 9 million are at risk from other ototraumatic agents. Occupational hearing loss knows no boundaries with respect to industries. Any worker, young or old, male or female, risks hearing loss when exposed to ototraumatic agents. Once the loss is acquired, it is irreversible.

Although noise-induced occupational hearing loss is the most common occupational disease and is the second most self-reported occupational illness or injury, it has not been possible to create a sense of urgency about this problem. Efforts to prevent occupational hearing loss have been hindered because the problem is insidious and occurs without pain or obvious physical abnormalities in affected workers.

Problems created by occupational hearing loss include the following: (1) reduced quality of life because of social isolation and unrelenting tinnitus (ringing in the ears), (2) impaired communication with family members, the public, and coworkers, (3) diminished ability to monitor the work environment (warning signals, equipment sounds, etc.), (4) lost productivity and increased accidents resulting from impaired communication and isolation, and (5) expenses for workers' compensation and hearing aids.

Because no national surveillance or injury-reporting system exists, no generalizable data are available regarding the economic impact of occupational hearing loss.

Research Opportunities

A great deal of information exists about the most important cause of hearing loss--high levels of damaging types of noise. Scientists are just beginning to understand how other factors such as exposure to solvents and heat affect hearing ability (acuity). However, many critical practical problems associated with stopping noise-induced hearing loss are largely unstudied. There have been no recent studies of the hearing status of contemporary workers. Reliance on data collected 30 years ago results in predictions that underestimate the amount of hearing loss that is due to occupational noise, especially for those with intermittent noise exposures. Moreover, factors such as heat and chemicals are only now emerging as recognized threats to hearing. Existing hearing conservation measures provide no guarantee to workers that occupational hearing loss will be prevented by the simple use of hearing protectors. For example, removing hearing protection for 15 minutes of an 8-hour work shift can cut protection effectiveness in half; yet we know little about why protection is not worn. Likewise, a poorly-fitting hearing protector will not prevent hearing loss. Research will give employers and employees strategies to identify and overcome barriers to the use of hearing protection. It will provide new methods to reduce noise exposure-- such as ways to block noise at its sources and to assure that hearing protection fits the wearer. Research will also determine the impact of other risk factors for hearing loss and will examine why some people seem to be susceptible to hearing loss. In addition, research will also: (1) redefine the risk of occupational hearing loss, taking into account exposure times, exposure events, exposure agents, and the use of personal protective equipment; (2) develop and test new strategies for identifying exposure hazards; (3) develop and implement new technologies for controlling noise and improving hearing protector effectiveness; and (4) initiate new methods to improve the efficiency of biological monitoring for hearing loss and the effectiveness of hearing loss prevention programs.

Infectious Diseases

Health care workers are at risk of tuberculosis (TB), hepatitis B and C viruses, and the human immunodeficiency virus (HIV). Social service workers, corrections personnel, and other occupational groups who work regularly with populations having increased rates of TB may also face increased risk. Laboratory workers are at risk of exposure to infectious diseases when working with infective material. Research is needed to determine the extent of occupational transmission of these infectious diseases, to understand the barriers to the use of safe work practices and vaccines, and to develop and evaluate new control methods.

Importance

Infections acquired in the work setting are a diverse group with many different modes of transmission. Of particular concern are infectious diseases transmitted by humans (e.g., from patient to worker or from worker to worker) in a variety of work settings. Bloodborne and airborne pathogens represent a significant class of exposures for the 6 million U.S. health care workers. Occupational transmission of bloodborne pathogens (including the hepatitis B and C virus and the human immunodeficiency virus [HIV]), occurs primarily by means of needle-stick injuries but also through exposures to the eyes or mucous membranes. The risk of hepatitis B virus infection following a single needle-stick injury with a contaminated needle varies from 2% to greater than 40%, depending on the antigen status of the source patient. Similarly, the risk of hepatitis C virus transmission also depends on the status of the source and ranges from 3.3% to 10%. Before widespread use of hepatitis B virus vaccine, approximately 8,700 acute cases of hepatitis B virus infection were reported among health care workers each year. Although the incidence of occupational hepatitis C virus infection among these workers is unknown, antibody to hepatitis C virus (evidence of previous infection) is found in 1% of hospital-based health care workers. As of June 1995, the Centers for Disease Control and Prevention reported 143 U.S. health care workers with documented or possible occupational transmission of HIV.

Transmission of tuberculosis (TB) within health care settings (especially multidrug-resistant TB) has re-emerged as a major public health problem. Since 1989, outbreaks of this type of TB have been reported in 14 hospitals and at least 17 workers have developed active drug-resistant TB. In addition among workers in health care, social service, and corrections facilities who work with populations at increased risk of TB, hundreds have experienced tuberculin skin test conversions. Reliable data are lacking on the extent of possible work-related TB transmission among other groups of workers at risk for exposure.

Some cases of influenza and other communicable respiratory infections are surely due to exposure to infected persons at work. These are not generally considered occupational diseases, and the proportion acquired at work (from coworkers, patients, customers, clients, and the general public) is unknown. The cost of lost work time and decreased productivity is likely to be substantial.

Research Opportunities

Occupation is a major risk factor for nearly all communicable infections among adults. There are great demands for research on occupational transmission of infectious diseases occurring in the health care industry, where workers may often be exposed to populations with high prevalences of TB, HIV, or other bloodborne pathogens. Intervention research is especially needed. For example, many new needle-containing devices are marketed for improved safety, but there has been little evaluation of their effectiveness. Latex rubber gloves are routinely used as part of an overall strategy to prevent transmission of bloodborne infections. These gloves are the primary type of hand protection available to health care workers, yet glove wearers must also worry about increasing reports of latex allergies following their use. As with other regulations, the implementation and effectiveness of the OSHA "bloodborne pathogens" standard should be evaluated, as should the CDC Guidelines for Preventing the Transmission of Mycobacterium Tuberculosis in Health Care Facilities. The resurgence of TB and the increase in multidrug-resistant strains have made it difficult to assure the safety of health care workers. Research is needed to design interventions and to evaluate the protection achieved by using ventilation and air filtration, ultraviolet germicidal irradiation, and respirators.

In addition to posing a risk for health care providers, work exposures may also be a major risk factor for many communicable infections among adults in a variety of workplace settings. Hence, research is also needed to define the incidence, prevalence, and impact of occupational infectious diseases such as acute respiratory illness and vaccine-preventable illnesses.

Low Back Disorders

Low back musculoskeletal disorders are common and costly. Although the causes of low back disorders are complex, substantial scientific evidence identifies some work activities and awkward postures as significantly contributing to the problem. In the United States, back disorders account for 27 percent of all nonfatal occupational injuries and illnesses involving days away from work. Prevention activities should be undertaken based on current knowledge, but important new research efforts are needed to assure that work-related low back disorders are successfully prevented and treated. For some occupations and tasks, there is a pressing need for more information about safe levels of exposure and for further validation of promising intervention approaches such as mechanical lifting devices for nursing aides.

Importance

Back pain is one of the most common and significant musculoskeletal problems in the world. In 1993, back disorders accounted for 27% of all nonfatal occupational injuries and illnesses involving days away from work in the United States. The economic costs of low back disorders are staggering. In a recent study, the average cost of a workers' compensation claim for a low back disorder was $8,300, which was more than twice the average cost of $4,075 for all compensable claims combined. Estimates of the total cost of low back pain to society in 1990 were between $50 billion and $100 billion per year, with a significant share (about $11 billion) borne by the workers' compensation system. Moreover, as many as 30% of American workers are employed in jobs that routinely require them to perform activities that may increase risk of developing low back disorders.

Despite the overwhelming statistics on the magnitude of the problem, more complete information is needed to assess how changes implemented to reduce the physical demands of jobs will affect workplace safety and productivity in the future. A tremendous opportunity exists for prevention efforts to reduce the prevalence and costs of low back disorders, since a significant number of occupationally related low back disorders are associated with certain high-risk activities. For example, female nursing aides and licensed practical nurses were about two and one-half times more likely to experience a work-related low back disorder than all other female workers. Male construction laborers, carpenters, and truck and tractor operators were nearly two times more likely to experience a low back disorder than all other male workers.

Research Opportunities

Every worker whose job involves stressful lifting tasks or awkward postures is at risk for a low back disorder. Countless times each day the health aide in a nursing home lifts and physically assists elderly or disabled residents. Many construction laborers, agricultural workers and others spend their days lifting and carrying awkward loads. Often their productive work is interrupted by weeks of disability, pain, and costly therapy, yet little is known about the pathophysiology of low back pain. For some occupations and tasks, the risks are not well defined. How much weight is too much? How many lifts per day are too many? What are the material handling jobs with the highest risk of back injury? These are interrelated risk factors. They represent one broad challenge of research: to develop approaches by which employers, workers, design engineers, and others with a role in prevention can confidently identify hazardous and safe work tasks. Another challenge for those tasks and occupations involving recognized hazards is intervention research. Evaluation of rehabilitation and return to work strategies will be useful. Current studies are testing ways to reduce risks to nursing aides by the use of mechanical lifting devices, training, and reorganizing tasks. Studies of this type (including those testing the effectiveness of back belt use) are needed in other work settings. Research to redesign materials, loads, and equipment can improve the safety of workers in many occupations.

Musculoskeletal Disorders of the Upper Extremities

Musculoskeletal disorders of the upper extremities (such as carpal tunnel syndrome and rotator cuff tendinitis) due to work factors are common and occur in nearly all sectors of our economy. More than $2 billion in workers' compensation costs are spent annually on these work-related problems. Workers' compensation costs undoubtedly underestimate the actual magnitude of these disorders. Current scientific research has provided important insights into the etiology and prevention of these disorders, but important questions remain unsolved. Research needs include better methods of exposure characterization and greater understanding of basic pathophysiologic mechanisms.

Importance

Musculoskeletal disorders of the neck and upper extremities due to work factors affect employees in every type of workplace and include such diverse workers as food processors, automobile and electronics assemblers, carpenters, office data entry workers, grocery store cashiers, and garment workers. The highest rates of these disorders occur in the industries with a substantial amount of repetitive, forceful work. Musculoskeletal disorders affect the soft tissues of the neck, shoulder, elbow, hand, wrist, and fingers. These include the nerves (e.g., carpal tunnel syndrome), tendons (e.g., tenosynovitis, peritendinitis, epicondylitis), and muscles (e.g., tension neck syndrome). The costs associated with these disorders are high. More than $2.1 billion in workers' compensation costs and $90 million in indirect costs (hiring, training, overtime, and administrative costs) are incurred annually for these musculoskeletal disorders.

In 1994, 332,000 musculoskeletal disorders due to repeated trauma were reported in U.S. workplaces. This figure represents nearly 65% of all illness cases reported to the Bureau of Labor Statistics--an increase of nearly 10% compared with 1993 figures and more than 15% relative to 1992 figures.

The most frequently reported upper-extremity musculoskeletal disorders affect the hand/wrist region. In 1993, carpal tunnel syndrome, the most widely recognized condition, occurred at a rate of 5.2 per 10,000 full-time workers. This syndrome required the longest recuperation period of all conditions resulting in lost workdays, with a median 30 days away from work.

Research Opportunities

Research has made important gains by establishing widespread recognition of work-related musculoskeletal disorders of the upper extremities and identifying much about their principal causes and approaches to prevention. This research has instigated a wide field of prevention efforts at worksites throughout the United States. But research is still needed across the gamut of possible concerns, including basic research that clarifies the pathophysiologic mechanisms of chronic musculoskeletal injury. Employers and workers want to know: "How can these problems be solved cost effectively?" "What is causing the problem?" "How can we bring people back to work without being reinjured?" "How can these problems be solved with better cost-effective tool and equipment designs, work-rest periods, or changes in the organization of work?" Health care providers want reliable clinical methods to diagnose musculoskeletal disorders, identify them before they become severe, and rehabilitate disabled workers as fully and rapidly as possible. These many challenges are being met with varied and sporadic success. There is a large role for research to improve and standardize successful ways to address these challenges. This effort will require unraveling the ways in which different factors combine to cause a hazard, providing better approaches by which employers and workers can identify hazards before they cause injury, and developing and proving the effectiveness of interventions and treatment. This scientific work has an integral role in the occupational safety and health community's efforts to reverse the trend of the large and growing problem of upper-extremity musculoskeletal disorders.

Traumatic Injuries

Injury exacts a huge toll in U.S. workplaces--on an average day, 16 workers are killed and over 17,000 workers are injured. The associated economic costs are high--about $121 billion per year. Research should focus on leading causes and high-risk groups. Priorities are deaths caused by motor vehicles, machines, violence, and falls, as well as traumatic injuries caused by falls and contact with machines, materials, equipment, and tools. High-risk groups include construction workers, loggers, miners, farmers, farm workers, adolescents, and older workers. Multiple factors and risks contribute to traumatic injuries, including the characteristics of workers, workplace/process design, work organization, economics and other social factors. Research needs are thus broad, and the development of interventions involve many disciplines and organizations.

Importance

Fatal Occupational Injuries

During the period 1980 through 1992, more than 77,000 workers died as a result of work-related injuries. This means that an average of 16 workers die every day from injuries suffered at work. The leading causes of occupational injury fatalities over this 13-year period were motor vehicles, machines, homicides, falls, electrocutions, and falling objects. There were four industries--mining, construction, transportation, and agriculture--with occupational injury fatality rates that were notably and consistently higher than all other industries. Motor-vehicle-related deaths in the transportation sector, machine-related deaths in agriculture, electrocutions and fatal falls in construction, homicide in retail trade and public administration, and deaths due to falling objects in mining and logging appear to be important because of particularly high rates of death from injury.

Nonfatal Occupational Injuries

In 1994, 6.3 million workers suffered job-related injuries that resulted in lost work time, medical treatment other than first aid, loss of consciousness, restriction of work or motion, or transfer to another job. The leading causes of nonfatal occupational injuries involving time away from work in 1993 were overexertion, contact with objects or equipment, and falls to the same level. Industries experiencing the largest number of serious nonfatal injuries include eating and drinking places, hospitals, and grocery stores. Industries facing higher risks of serious nonfatal injuries are concentrated in the manufacturing sector and include workers in shipbuilding, wooden building and mobile home manufacture, foundries, special products sawmills, and meat packing plants.

Clearly, work-related injuries and fatalities result from multiple causes, affect different segments of the working population, and occur in a myriad of occupational and industrial settings. The total cost of work-related injuries and fatalities to industry and to society at large has not been fully recognized, but is estimated to be greater than $121 billion annually. Efforts to set research and prevention priorities in traumatic injury must be driven by data that illuminate the nature and magnitude of these injuries.

Research Opportunities

Relatively good general information is available on the overall burden of work injuries in the United States. There are expanding sources of information to identify the industries and occupations where they occur most frequently and with greatest severity. The challenge is to move beyond this broad understanding to specific strategies that actually prevent another warehouse employee from being crushed by an overturned forklift, prevent scaffolding from collapsing from under a mason, and keep convenience store clerks and taxi drivers from being shot or stabbed. At many worksites, such injuries are already largely prevented. The challenge is to develop information systems that allow new preventive efforts to target high-risk worksites and to develop solutions that fit highly specific hazardous circumstances. Specific strategies are needed within work sectors (e.g., agriculture and construction) that address the complex interplay between machines, tools, and behavioral and environmental factors causing injuries at a worksite. In many cases, understanding these factors will lead researchers to re-engineer work practices, equipment, and tools to eliminate hazards. For hazards that cannot be eliminated (such as exposure of fire fighters to fires, explosions, and toxic emissions), research will improve safety practices and the protective equipment and clothing worn by the worker.