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A relatively neglected topic in manual materials handling (MMH) research is the impact of the accuracy of task parameter measurements on the application of various assessment methods. A laboratory experiment was conducted to investigate the accuracy of NIOSH equation parameter measurements made by eight subjects following a 4-h training session. Five individual tasks were measured; two were single tasks and three were part of a multiple-component simulated palletizing operation. Significant differences between reference parameter measurements and average measurements made by subjects were found. The sensitivity analysis showed that frequency and horizontal location are the most important parameters. These parameters also tended to have the highest measurement errors. Recommendations for increasing the effectiveness of training programs for NIOSH equation users based on the results of the study are presented. [ABSTRACT FROM AUTHOR]

To determine if the contribution of slipperiness to occupational slip, trip and fall (STF)-related injuries could be isolated from injury surveillance systems in the USA, the UK and Sweden, six governmental systems and one industrial system were consulted. The systems varied in their capture approaches and the degree of documentation of exposure to slipping. The burden of STF-related occupational injury ranged from 20 to 40% of disabling occupational injuries in the developed countries studied. The annual direct cost of fall-related occupational injuries in the USA alone was estimated to be approximately US$6 billion. Slipperiness or slipping were found to contribute to between 40 and 50% of fall-related injuries. Slipperiness was more often a factor in same level falls than in falls to lower levels. The evaluation of the burden of slipperiness was hampered by design limitations in many of the data systems utilized. The resolution of large-scale injury registries should be improved by collecting more detailed incident sequence information to better define the full scope and contribution of slipperiness to occupational STF-related injuries. Such improvements would facilitate the allocation of prevention resources towards reduction of first-event risk factors such as slipping.

Background: Acute hand injury is the leading cause of occupational injury treated in United States' hospital emergency departments (e.g., laceration, crush or fracture). To identify risk factors for traumatic hand injuries, we conducted a case-crossover study of transient exposures (e.g., being rushed) for acute occupational traumatic hand injury., Methods: The case-crossover method, which uses subjects as their own controls, was used to identify risk factors for occupational hand injury. Two hundred and thirty-two subjects were recruited from 17 occupational health clinics in New England and interviewed by telephone a median of 1.2 days after their injury. The a priori hazard period was defined as 10 min before the injury. Two control periods were used: one was 60-70 min prior to the injury (matched-pair interval analysis); the other was the total work-time exposed, on average, in the previous month (usual frequency analysis)., Results: In the usual frequency analysis, the relative risk for using malfunctioning or different-from-usual equipment or tools in the hazard period was 25.5 (95% confidence interval = 18.4-35.2). Relative risks were also significantly elevated for performing a task using an unusual work method, doing an unusual task, being distracted, or being rushed. Wearing gloves appeared to be protective (relative risk = 0.8, 95% CI = 0.5-1.2). Matched-pair interval analysis, where appropriate, provided similar findings but had much wider confidence intervals., Conclusions: This study demonstrates that the case-crossover design is a feasible and efficient method for studying transient risk factors for sudden-onset traumatic occupational hand injury. The usual frequency analysis proved more useful than the match-pair approach to control period selection., (Copyright 2001 Wiley-Liss, Inc.)

Two hundred thirty-five work-related deaths occurred in the construction industry in a new economic development area in eastern China between 1991 and 1997. These fatalities represented 55% of all occupational deaths. The average annual mortality rate was 51.5 per 100,000 construction workers. Falls were the leading cause of death (46.4%). Falls, collisions, struck by/against something, electrocutions, and excavation cave-ins were the main fatality antecedents, accounting for nearly 93.6% of all fatalities. The most common antecedents for incidents with multiple fatalities were falls, crane-related events, poisoning, and fire. These categories of antecedents were similar to those encountered in the construction industry in the United States. These data suggest that organizations need to focus on these event types when planning their prevention activities. Moreover, improved surveillance systems including computerized databases with narrative descriptions of injury events, antecedent factors, and person-time at-risk data are needed to target interventions more precisely.

Fatal occupational injuries in a new development region in Shanghai in east China are described. All occupational deaths in the East Pujiang New Area during the period 1991 through 1997 were abstracted from multiple, overlapping source documents. There were 426 deaths and a crude mortality rate of 9.1 per 100,000 workers. The death rate was highest in 1995 (14.6%), when expansion in the area was most rapid. The construction sector accounted for 55% of the deaths, followed by manufacturing (23%) and transport, storage, and telecommunications (11%). Falls, collisions, struck by/against incidents, and electrocutions accounted for 80% of all deaths. Falls led all other causes of deaths (33%) and were particularly prevalent in the construction industry (46% of all deaths in construction). The development of ongoing, comprehensive injury surveillance systems in the People's Republic of China will be essential to target and evaluate injury prevention activities in the future.

A critical review was conducted of studies of work-related low back pain in the People's Republic of China. The published literature in both the English and Chinese languages from 1983 to 1997 was reviewed for studies that permitted the calculation of prevalence ratios. Thirty-five papers were identified initially, and after quality inclusion/exclusion criteria were applied, 16 (14 in Chinese and two in English) were selected for more detailed review. Prevalence ratios were statistically elevated in all but two of the selected studies. Prevalence ratios for individual groups ranged from 2.0 to 8.5 for bending and twisting, 1.5 to 14.3 for static posture, 1.9 to 5.5 for whole-body vibration, and 2.6 to 9.4 for low-temperature exposure. The literature was limited by the absence of standardized and robust measures of low-back-pain outcomes and exposures and by the omission of fundamental details from research reports. Even with these limitations, the review findings suggest that three physical risk factors, all well known in the international literature, are associated with the prevalence of low back pain in the People's Republic of China.

In this paper, we discuss the theoretical framework upon which observational studies of occupational injuries are based. Following a general description of how causal effects are estimated, the challenges faced by researchers working in this area are outlined, with an emphasis on case-control studies. These challenges include defining the at-risk period for workers whose tasks change over time and whose hazard period may be very brief, evaluating the underreporting of both exposures and injuries, and considering the effects of multiple injuries per individual on study design and data analysis. We review both the theoretical and practical considerations in the design and conduct of traditional case-control studies, based on the collection of individual level data, as well as other approaches, such as using information culled from administrative and descriptive databases, and case-control studies in which the plant or work site is the unit of analysis. The case-crossover design is also reviewed and its utility for reducing confounding due to differences between individuals by self-matching is highlighted. While this design has not yet been applied to the work setting, its potential for increasing our understanding of the causes of acute-onset occupational injuries seems promising. Finally, a variety of hybrid designs are discussed, including combinations of case-control, case-crossover, and cohort designs.

Occupational and work-related injuries comprise the majority of reported workplace morbidity in the employed population in the United States. Despite intervention attempts, the overall trend for these injuries has been relatively stable over the past several decades. Three significant problems are raised as potentially contributing to this stability. Minimal progress in reduction may be due to: lack of etiologic understanding, lack of appropriate intervention selection, or lack of appropriate intervention implementation. Focusing on the first of these problems, a workshop symposium of injury epidemiologists and related scientists was held that developed a series of collaborative manuscripts on issues in injury epidemiology and recommendations for future research. The contributions of each are briefly summarized.

Despite increased attention to the epidemiology of occupational injuries and work-related musculoskeletal disorders, little is known about the relative contribution of risk factors for specific injuries and diseases and effective ways to prevent them. Building on the knowledge and ideas presented in the previous papers in this special issue, this paper describes the salient issues regarding the needs and the opportunities in design, conduct, and analysis of epidemiologic research on occupational injury. There is a clear need for standardization of definitions on exposure variables and health outcomes, since basic terminology is not used consistently across studies. Improved surveillance systems with linkage to other databases offer excellent opportunities to evaluate trends in risk factors and occupational injuries. New opportunities for etiologic studies include the case-crossover design, which focuses on relations between intermittent exposures and injuries, as well as several hybrid designs that combine advantages and strength of the traditional case-control and cohort study designs. Various suggestions are presented to capture the dynamics of exposure, including both intermittent and continuous factors in the assessment strategy. The importance of cohort studies is emphasized to clarify the temporal relations between causes and effects in work-related injury research. Finally, intervention studies are much needed and a hierarchical approach is suggested, starting with observational surveys, continuing with quasi-experimental studies and concluding with randomized controlled experiments of those interventions that hold the largest promise.

This paper reviews surveillance approaches for occupational injuries and evaluates three emerging methodologies for the enhancement of work-related injury surveillance: (1) narrative data analysis, (2) data set linkage, and (3) comprehensive company-wide surveillance systems. All three methods are the result of new applications of computer hardware and software that have apparent strengths and limitations. A major strength is the improved description of work exposures and related injuries leading to better understanding of injury etiology. This understanding, however, is limited by the data quality and completeness entered on records at the time of the injury. We recommend (1) more widespread inclusion of narrative text in databases, analyses of which can be a valuable supplement to injury coded data; (2) the increased use of data set linkage studies to combine injury and work-history data; and (3) the development of comprehensive company-wide surveillance systems to expedite the use of epidemiologic data for occupational injury prevention activities. Further development of these methods and others is encouraged, especially in light of technological advancements in data capture, analysis and presentation. Only through such efforts can we best apply epidemiologic principles to preventing injuries in the workplace.

This is the first large-scale study of US workers that describes the demographic and cost differences between recurrent and nonrecurrent low back pain (LBP) disability claimants, using data from a large workers' compensation insurer. Persons with at least one LBP claim in 1990 and one or more additional claims in 1990 to 1996 were defined as recurrent. Persons with at least one LBP claim in 1990 but no subsequent claims were defined as nonrecurrent. Fourteen percent of claimants were recurrent. The percentage of recurrent claimants who were male (77.2%) was higher than the percentage that were female (22.8%). This difference was more pronounced in the younger age groups. The median total cost for recurrent LBP claims in 1990 was 4% greater than for nonrecurrent 1990 LBP claims, whereas the mean cost was 48% less. Most studies of LBP recurrence among US workers have followed single-corporation employees. Our rate of recurrence was lower than these previously reported rates. However, analysis of independent workers' compensation insurance company data may provide a more accurate assessment of LBP claim recurrence among US workers.

Setting priorities for workplace health and safety research depends upon accurate and reliable injury and illness data. All occupational health databases have limitations when used to summarize the national scope of workplace hazards. The comparison of data from multiple sources may produce more credible estimates of the leading occupational injuries and illnesses. The purpose of this paper is to describe the strengths and weaknesses of six data collection systems that record occupational injuries and illnesses on a national level and to compare the leading estimates from these systems for 1990. The six systems are: 1) National Traumatic Occupational Fatalities database, 2) the Bureau of Labor Statistics Census of Fatal Occupational Injuries, 3) The Bureau of Labor Statistics Annual Survey data, 4) a large workers' compensation database, 5) the National Council on Compensation Insurance data, and 6) The National Electronic Injury Surveillance System. Occupational injuries, as defined herein, predominate over illnesses in terms of the number of cases and the overall costs. Databases that provide information on the antecedents of injuries suggest how these injuries may be prevented and warrant more attention and refinement.

The increasing trends of cumulative trauma disorders of the upper extremities (CTDUEs) in US industry is well established; however, systematic examination of potential reasons for these trends has been lacking. Data from the United States Bureau of Labor Statistics and from Liberty Mutual Group workers' compensation claims were used to count CTDUEs. The proportions of all Bureau of Labor Statistics' cases and Liberty Mutual Group workers' compensation claims that resulted from CTDUEs were estimated for the years 1986 to 1993. The proportions by occupation (job classification code), gender, potential video display unit use, and in the meat-packing industry are described. Both data systems show a steady increase in cases and claims from less than 1% in 1986 to about 4% in 1993. Women and specific occupational categories are over-represented with respect to CTDUEs. A shift to service industry work and video display unit use do not appear to be strongly related to the increased reporting of CTDUEs, whereas increased productivity, an increased number of women in the work force and general awareness of CTDUEs in the media and health care system may be related. Coding and definition problems still limit these conclusions, however.

Ergonomics and epidemiology are unique fields that share some common interests. Epidemiologic methods are increasingly being utilized in ergonomic studies of the work-related risk factors of musculoskeletal disorders. This multidisciplinary approach requires a shared knowledge base and understanding of the methodology of both disciplines. In this paper, basic epidemiologic concepts are introduced. Examples from the upper extremity musculoskeletal disorder literature are used to illustrate study design issues and to suggest improved study methods. Epidemiologic design problems including selection bias (healthy worker survivor effect), misclassification, and confounding are discussed. Prospective research designs are described as a feasible approach for the study of these disorders. Increased collaboration between ergonomists and epidemiologists is encouraged to improve progress towards the reduction of workplace injuries and illnesses.

Work in the construction industry involves about a threefold increased risk of fatal injury compared with all industries combined. The purpose of this study was to identify potential risk factors for fatal injury in the construction industry in New Jersey. Multiple data sources including death certificates, medical examiner reports, Occupational Safety and Health fatality files, and Workers' Compensation reports were used to identify 200 construction-related fatalities in New Jersey during the years 1983 to 1989. All deaths were in men. The death rate was 14.5 per 100,000 employed person-years over the study period. Death rates tended to diminish with increasing age after 34 until age 65 when the death rate was the highest (27.7). Death rates were higher for Hispanics (34.8) and African-Americans (24) than whites (10.6). Ironworkers and roofers had highest rates (109.0 and 56.2, respectively) among specific occupational groups within the construction industry. The leading cause of death was falls (46%). These data suggest that intervention efforts directed toward workers at heights is needed. Further research is warranted to elucidate the factors contributing to the elevated fatality rate of workers over age 65, and to Hispanic and African-American workers.

About 19,000 finger amputations occur at work each year in the United States. Twenty percent of these injuries are severe enough to require hospitalization. Hospital discharge data from New Jersey (1985, 1986) were used to describe the demographic characteristics of persons with such injuries and to identify potential subjects for telephone interview. A total of 637 persons hospitalized for finger amputations were sent letters asking for their participation. Of 637 persons, 355 (56%) were contacted and 228 (36%) were interviewed, of whom 134 (59%) said their injury occurred at work. The annual rate of finger amputations at work was 9.3 per 100,000 employed persons. The rate was higher for males (14.7) than females (1.9). The age-adjusted rates were higher for Hispanic (52.8) and black (28.9) males than for white males (9.5). Persons working with machines or maintaining them in the manufacturing industry were at highest risk. Unjamming or repairing machinery (e.g., presses, saws, or slicers) while in operation was particularly hazardous. These data can be used to target occupations and industries for specific worksite intervention to prevent finger amputations. One limitation of this study, however, is that hospitalized occupational finger amputations may not be representative of all finger amputations, the majority of which are less severe and do not require hospitalization.

Computerized population-based hospital discharge data in New Jersey offer new opportunities for surveillance of serious work-related injuries. This database was evaluated for its potential in identifying selected injuries that occurred at work during 1985 and 1986. Hospital discharge data were compared with data collected by telephone interview of discharged patients. A total of 1,575 unique hospital discharge records for the selected injuries included finger amputation (1,041), thumb amputation (209), crush injury of the lower limb (208), toxic effects of heavy metals (69), and eye burns (48). Of 809 study subjects sent letters, 445 (55%) could be contacted and 289 (36%) were interviewed for the study. Sixty-one percent (175) said their injury was work related. A comparison was made between self-reported injury at work, and the presence of workers' compensation payer codes on the discharge database. The agreement beyond chance (Kappa) was 0.78 (95% CI = 0.67, 0.89). The sensitivity of this indicator of work relatedness was 83%; specificity was 98%. These data suggest that workers' compensation payment on the hospital discharge database may be a good to excellent proxy indicator of the work relatedness of these injuries. However, this proxy indicator will underestimate the number of work-related injuries by about 20%. Only 11% of hospital discharge records had external cause of injury codes (E-codes), which reduces the utility of the database for understanding the causal mechanisms of work-related injuries.

Harmful psychological and physical consequences may result when elderly people fall. I summarize the epidemiology of falls among elderly people and focus on three potentially remediable causes of falls: reduced peripheral neurosensation, the use of psychoactive medication, and environmental hazards. From 1960 to 1980, death rates from falls among white persons 75 years of age and older have decreased by more than 50%. Fall rates among community-dwelling elderly people increase with age and are greater for women than men. The death rates from falls, however, are now greater for men than women. Reduced peripheral neurosensation in the lower extremities may be a significant cause of falls among the elderly. Recreational walking or physical therapy may improve these deficits and lead to fewer falls. The use of psychoactive medications, most commonly benzodiazepine sedatives, is possibly associated with an increased risk of falls and hip fractures; greater caution in the use of these medications is warranted. The elimination or redesign of steps and curbs and the provision of hand railings and walking aids may be the most effective environmental approaches to preventing falls. These conclusions need further study in community-dwelling elderly populations.