Evaluation of direct workers' compensation costs for musculoskeletal injuries surrounding interventions to reduce patient lifting.

OBJECTIVES: We evaluated costs for workers' compensation (WC) injuries of a musculoskeletal (MS) nature in a large tertiary care hospital and an affiliated community hospital in the 13 years surrounding an institution-wide shift to a 'minimal manual patient-lifting environment' supported with inpatient mechanical lift equipment. METHODS: Negative binomial regression was used to model adjusted and discounted payment rates based on full-time equivalents (FTEs), and payment ratios. The risk of higher cost was assessed based on type of injury (patient-handling vs non-patient-handling), hospital, job, age, gender, institutional tenure and time since the implementation of lift equipment. Lagging was used to evaluate the latency of the intervention effect. RESULTS: Patient-handling injuries (n=1543) were responsible for 72% of MS injuries and 53% of compensation costs among patient care staff. Mean costs per claim were 5 times higher for those over age 45 than those <25 years of age. Physical and occupational therapy aides had the highest cost rates ($578/FTE) followed by nursing aides ($347/FTE) and patient transporters ($185/FTE). There was an immediate, marked decline in mean costs per claim and costs per FTE following the policy change and delivery of lift equipment. CONCLUSIONS: The observed patterns of changes in cost likely reflect the effects of activities other than use of lift equipment, including targeted efforts to close WC claims and an almost simultaneous policy that shifted cost responsibility to the budgets of managers on individual units. Inference was facilitated through the use of longitudinal data on the workgroups and an internal injury comparison.

Lung cancer mortality and fibre exposures among North Carolina asbestos textile workers.

OBJECTIVE: To describe mortality among workers exposed to chrysotile asbestos and evaluate the relationship between lung cancer and asbestos fibre exposure. METHODS: Workers employed for at least 1 day between 1 January 1950 and 31 December 1973 in any of four plants in North Carolina, USA that produced asbestos textile products were enumerated. Vital status was ascertained through 31 December 2003. Historical exposures to asbestos fibres were estimated from work histories and 3578 industrial hygiene measurements taken in 1935-1986. Mortality of the cohort was compared with that of the national population via standardised mortality ratios (SMRs). Exposure-response relationships for lung cancer were examined within the cohort using Poisson regression to compute adjusted mortality rate ratios. RESULTS: Follow-up of 5770 workers included in the cohort resulted in 181 640 person-years of observation, with 2583 deaths from all causes and 277 from lung cancer. Mortality from all causes, all cancers and lung cancer was significant higher than expected, with SMRs of 1.47 for all causes, 1.41 for all cancer and 1.96 (95% CI 1.73 to 2.20) for lung cancer. SMRs for pleural cancer, mesothelioma and pneumoconiosis were also elevated. The risk of lung cancer and asbestosis increased with cumulative fibre exposure (RR 1.102 per 100 fibre-year/ml, 95% CI 1.044 to 1.164, and RR 1.249 per 100 fibre-year/ml, 95% CI 1.186 to 1.316, respectively, for total career exposure). CONCLUSIONS: This study provides further evidence that exposure to chrysotile asbestos in textile manufacturing is associated with increased risk of lung cancer, asbestosis cancer of the pleura and mesothelioma.

Estimates of historical exposures by phase contrast and transmission electron microscopy in North Carolina USA asbestos textile plants.

OBJECTIVES: To develop a job-exposure matrix (JEM) for fibre exposures in three asbestos textile plants and to develop estimates of fibre size-specific exposures. METHODS: Historical dust samples from three North Carolina, USA asbestos textile plants were obtained. Plant specific samples were used to express impinger dust concentrations as fibre concentrations by phase contract microscopy (PCM). Mixed models were used to estimate PCM exposures by plant, department, job and calendar time. Archived membrane filter samples were analysed by transmission electron microscopy (TEM) to determine the bivariate diameter/length distribution of airborne fibres by plant and operation. RESULTS: PCM fibre levels estimated from the models were very high in the 1930s, with some operations having in excess of 200 fibres/ml, and decreased appreciably over time. TEM results for 77 airborne dust samples found that only a small proportion of airborne fibres were measured by PCM (>0.25 microm in diameter and >5 microm in length) and the proportion varied considerably by plant and operation (range 2.9% to 10.0%). The bivariate diameter/length distribution of airborne fibres demonstrated a relatively high degree of variability by plant and operation. PCM adjustment factors also varied substantially across plants and operations. CONCLUSIONS: These data provide new information concerning airborne fibre levels and characteristics in three historically important asbestos textile plants. PCM concentrations were high in the early years and TEM data demonstrate that the vast majority of airborne fibres inhaled by the workers were shorter than 5 microm in length, and thus not included in the PCM-based fibre counts.

Occupational injuries among aides and nurses in acute care.

BACKGROUND: Occupational injuries are common among nursing personnel. Most epidemiologic research on nursing aides comes from long-term care settings. Reports from acute care settings often combine data on nurses and aides even though their job requirements and personal characteristics are quite different. Our objective was to assess risk of work-related injuries in an acute care setting while contrasting injuries of aides and nurses. METHODS: A retrospective cohort of aides (n = 1,689) and nurses (n = 5,082) working in acute care at a large healthcare system between 1997 and 2004 were identified via personnel records. Workers' compensation filings were used to ascertain occupational injuries. Poisson regression was used to estimate rate ratios (RR) and 95% confidence intervals (95% CI). RESULTS: Aides had higher overall injury rates than nurses for no-lost work time (RR = 1.2, 95% CI: 1.1-1.3) and lost work time (RR = 2.8, 95% CI: 2.1-3.8) injuries. The risk of an injury due to lifting was greater among aides compared to nurses for both non-lost work time and lost work time injuries. Injury rates among aides were particularly high in rehabilitation and orthopedics units. Most of the injuries requiring time away from work for both groups were related to the process of delivering direct patient care. CONCLUSIONS: Our findings illustrate the importance of evaluating work-related injuries separately for aides and nurses, given differences in injury risk profiles and injury outcomes. It is particularly important that occupational safety needs of aides be addressed as this occupation experiences significant job growth.

Systematic reviews of workplace injury interventions: what are we missing?

BACKGROUND: There are pitfalls associated with applying a biomedical model with its emphasis on experimental designs to the evaluation of workplace injury interventions. OBJECTIVES: Evaluation over enough time is essential in occupational safety when interventions are expected to have a latent effect as well as to assess sustained effects. Controlled trials are not well-suited to this task and are not even possible in circumstances where a policy change, such as legislative action, affects a population of workers simultaneously. Social context influences occupational injury interventions, their evaluation and the wider generalization of findings but is lost in the pooling of data for meta-analyses. Some of these issues can be addressed through recognition of the contribution of diverse observational methodologies in intervention evaluation, improvement and maintenance of robust surveillance systems, and inclusion of qualitative methodologies not typically embraced by epidemiologists or medical researchers. METHODS: Through consideration of an evaluation of a legislative effort to prevent falls from height in construction, we demonstrate lack of flexibility in current methods used for evaluating time series analyses in systematic reviews of occupational injury intervention effectiveness. DISCUSSION AND CONCLUSIONS: These include the manner in which downward change in slope is assessed and the call to demonstrate a significant initial downward change in level. We illustrate essential contextual detail regarding this intervention that is lost in the pooling of data from multiple studies into a combined measure of effect. This reduction of occupational injury intervention evaluation to one of pure statistical significance is ill-conceived, irresponsible, and should be stopped.

Development of a fibre size-specific job-exposure matrix for airborne asbestos fibres.

OBJECTIVE: To develop a method for estimating fibre size-specific exposures to airborne asbestos dust for use in epidemiological investigations of exposure-response relations. METHODS: Archived membrane filter samples collected at a Charleston, South Carolina asbestos textile plant during 1964-8 were analysed by transmission electron microscopy (TEM) to determine the bivariate diameter/length distribution of airborne fibres by plant operation. The protocol used for these analyses was based on the direct transfer method published by the International Standards Organization (ISO), modified to enhance fibre size determinations, especially for long fibres. Procedures to adjust standard phase contrast microscopy (PCM) fibre concentration measures using the TEM data in a job-exposure matrix (JEM) were developed in order to estimate fibre size-specific exposures. RESULTS: A total of 84 airborne dust samples were used to measure diameter and length for over 18,000 fibres or fibre bundles. Consistent with previous studies, a small proportion of airborne fibres were longer than >5 microm in length, but the proportion varied considerably by plant operation (range 6.9% to 20.8%). The bivariate diameter/length distribution of airborne fibres was expressed as the proportion of fibres in 20 size-specific cells and this distribution demonstrated a relatively high degree of variability by plant operation. PCM adjustment factors also varied substantially across plant operations. CONCLUSIONS: These data provide new information concerning the airborne fibre characteristics for a previously studied textile facility. The TEM data demonstrate that the vast majority of airborne fibres inhaled by the workers were shorter than 5 mum in length, and thus not included in the PCM-based fibre counts. The TEM data were used to develop a new fibre size-specific JEM for use in an updated cohort mortality study to investigate the role of fibre dimension in the development of asbestos-related lung diseases.

Inhalation exposure system used for acute and repeated-dose methyl isocyanate exposures of laboratory animals.

Laboratory animals were exposed by inhalation for 2 hr/day (acute) or 6 hr/day (four consecutive days, repeated dose) to methyl isocyanate (MIC). Exposures were conducted in stainless steel and glass inhalation exposure chambers placed in stainless steel, wire mesh cages. MIC was delivered with nitrogen via stainless steel and Teflon supply lines. Chamber concentrations ranged from 0 to 60 ppm and were monitored continuously with infrared spectrophotometers to 1 ppm and at 2-hr intervals to 20 ppb with a high performance liquid chromatograph equipped with a fluorescence detector. Other operational parameters monitored on a continuous basis included chamber temperature (20-27 degrees C), relative humidity (31-64%), static (transmural) pressure (-0.3 in.), and flow (300-500 L/min). The computer-assistance system interfaced with the inhalation exposure laboratory is described in detail, including the analytical instrumentation calibration system used throughout this investigation.

Epidemiology of asbestos-related diseases.

This paper is intended to give the reader an overview of the epidemiology of asbestos-related diseases and is restricted to primarily occupational exposure studies. However, some mention of nonoccupational exposures are made because of their direct relationship to a worker or to a secondary occupational source. Over 100 epidemiological studies are reviewed, dating back to the first case of asbestos-associated disease reported by Montague Murray in 1906. The studies are divided by specific fiber type and by specific disease outcomes and the interaction of asbestos and cigarette smoking is discussed in great detail.

Contribution of environmental fibers to respiratory cancer.

This article reviews studies of the carcinogenicity of mineral fibers, notably asbestos, and presents seven major recommendations for further research. Mineral fibers represent the greatest cause--after cigarette smoke--of respiratory cancer due to air pollutants. Past asbestos exposure may currently account for 2000 mesothelioma deaths per year and 4000 to 6000 lung cancer deaths per year. All major commercial types of asbestos (crocidolite, amosite, and chrysotile) can cause each of the major asbestos-related respiratory diseases. Lung cancers in asbestos-exposed individuals probably do not have a different distribution of histological types from that of non-asbestos-related lung cancers. Nonoccupational exposures are likely to be associated with malignant disease outcomes qualitatively similar to those associated with occupational exposures. Further investigations of fibers are needed to characterize the relationships among physicochemical properties, patterns of migration and clearance, dose, and adverse health effects. Transmission electron microscopy has been found to be the preferred method of analysis of environmental fibers. Relations among time factors (e.g., age at first exposure), dose, and risk for adverse health effects require analyses of existing and new epidemiologic studies of exposed cohorts. Concomitant exposure, behavioral factors, and host factors affecting susceptibility to asbestos should be identified.

Latency analysis in occupational epidemiology.

Allowance for prolonged disease induction and latency times is an important consideration in occupational epidemiology studies of cancer and other delayed effects of exposure. Two useful approaches for assessing prolonged induction and latency periods are (1) exposure lagging and (2) considering exposures only within moving time windows. The exposure weighting scheme proposed by Jahr2 to assess exposure burdens is another method that accounts for induction and latency, although not explicitly. These three approaches, which are shown to be special cases of exposure weighting, are illustrated with an analysis of lung cancer mortality among a cohort of workers from an asbestos textile plant.

Physical assault among nursing staff employed in acute care.

Hospital workers are known to be at risk of physical assault. The objective of this study is to characterize injuries resulting from physical assault among hospital nursing staff and to identify associated risk factors. Workers' compensation reports linked to human resources data were used to identify a cohort of aides and nurses employed in acute care units at a major healthcare system from 1997 to 2004 and their reported physical assault events. Poisson regression methods were used to estimate rates and rate ratios (RR) by occupation, gender, race, age, tenure, and hospital unit. During the study period 220 assaults were reported; the overall incidence rate was 1.65 (95% CI: 1.45-1.89) per 100 full-time-equivalent employees (FTEs). Assault risk was higher among those with shorter tenure (< 5 years vs. 15 or more) (RR=1.35, 95% CI: 0.83-2.19) and younger workers (under age 30 vs. 50 or older) (RR=1.30, 95% CI: 0.78-2.19), and lower among Black workers (vs. non-Blacks) (RR=0.63, 95% CI: 0.45-0.90). Incidence rates were highest in Psychiatry (12.65, 95% CI: 8.90-17.99), Neurology (4.43, 95% CI: 3.17-6.20) and Rehabilitation (3.63, 95% CI: 1.51-8.71) units. Interventions targeting Psychiatry, Neurology, and Rehabilitation units, and younger and newly hired staff are warranted. More detailed data are needed to develop targeted interventions.

Are we failing vulnerable workers? The case of black women in poultry processing in rural North Carolina.

In 1989, North Carolina Occupational Safety and Health Administration (OSHA) inspectors cited two poultry processing plants in northeastern North Carolina for serious repetitive motion problems. In 1990, investigators from the National Institute for Occupational Safety and Health confirmed significant upper extremity musculoskeletal symptoms and disorders among workers. We now report on analyses of baseline data collected from a cohort of women employed in one of these plants. The plant, which is the largest employer of women in the area, is located in a sparsely populated area with a black majority where nearly one-third of the population lives below the poverty level. Conditions we report suggest failure of existing health and safety systems, both regulatory and consultative, to prevent morbidity among vulnerable women in this industry, as well as social and economic conditions that influence availability of work and use of benefits to which they are entitled.

Musculoskeletal symptoms among poultry processing workers and a community comparison group: Black women in low-wage jobs in the rural South.

BACKGROUND: Poultry processing is characterized by rapid line speed and extreme division of labor. Morbidity associated with this work has been reported by scientists, journalists and workers in this fast growing industry. METHODS: Cross-sectional data from baseline measures of a cohort of black women employed in poultry processing (n = 291) and a community comparison group (n = 299) in rural North Carolina were used to evaluate musculoskeletal symptom reports and to explore factors associated with those reports. Recruitment of participants and collection of data were performed by women in the community circumventing the need to involve employers. RESULTS: Significant differences in musculoskeletal symptom prevalence were observed between women employed in poultry processing and those of similar economic status employed elsewhere in the same area of rural northeastern North Carolina. After adjusting for other factors independently associated with symptoms among these women including age, depression, and perceived isometric load at work, the prevalence of upper extremity and neck symptoms was 2.4 (95% CI 1.7, 3.2) times higher among women working in poultry processing. CONCLUSIONS: The findings add to the documentation of occupational health concerns among vulnerable workers employed in poultry processing in our state; in this economically depressed area of rural northeastern North Carolina poultry processing is the largest single employer of women. On a larger scale, the potential magnitude of upper extremity morbidity among women employed in poultry processing should be viewed with the knowledge that poultry processing is a growing industry in the U.S. with work done largely by blacks and immigrants.