Work-related asthma in cobalt-exposed workers.

OBJECTIVE: Workers exposed to cobalt may develop two lung conditions, asthma or lung fibrosis. There is a relative lack of awareness of the risk of lung disease from cobalt exposure. METHODS: The state of Michigan requires physicians, and hospitals to report work-related asthma (WRA). A standardized telephone interview of each reported case was conducted. An industrial hygienist evaluated the reported cases's workplace, and a physician reviewed the results to confirm the diagnosis. This is a population-based case series of all workers in whom the exposure to cobalt was confirmed as likely responsible for WRA from 1988 to 2017. We also included an illustrative case report and data on the workplace evaluations. RESULTS: Of the 35 cases identified, 77% were males, 97.1% were white, and 62.9% had a history of smoking cigarettes. Fifteen (44%) cases were involved in manufacturing cutting tools and machine tool accessories. Symptoms improved in 28 cases (80%) when away from work. Fourteen cases (40%) had emergency department visits, while 10 (28.6%) had been hospitalized for breathing problems. Spirometry had been performed for 33 (94.3%) cases. Only 13 (37.1%) reported they were informed by a doctor that their asthma was work-related. Twenty-six inspections were conducted at 21 different workplaces, where 498 coworkers were interviewed, 55 (11%) of which had respiratory symptoms at work. Six workplaces were cited for cobalt air level higher than permissible limits. These inspections resulted in $29,380 in penalties. CONCLUSIONS: WRA secondary to cobalt is associated with significant morbidity. Most of the cases were unaware of their medical diagnosis.

Hypersensitivity pneumonitis and antigen identification--An alternate approach.

OBJECTIVES: Identification of the causal antigen for patients with hypersensitivity pneumonitis (HP) is challenging in a standard clinical setting. The purpose of this pilot study was to determine whether it was possible to evaluate the home/workplace of patients, and identify the causal antigen. METHODS: Using a case-control study design we compared the presence of antibody to antigen collected in the environment of individuals with HP and controls consisting of family members/co-workers. Based on patient interviews, homes/workplaces were evaluated and suspected sources of antigen collected for use in immunoassays. RESULTS: Nineteen individuals with HP participated with 15 classified as having fibrotic disease. Up to 54 bulk samples were collected from each patient's environment, with multiple isolates (antigens) cultured from each. Of the seven individuals who tested positive to one or more environmental samples, three had a positive response to more than 1 antigen from the environmental sample (range 1-9). Twelve individuals tested positive to antigen(s) on a standard panel, with only one overlapping with the antigen from the home/workplace sample. A significant association existed between results of interviews/site evaluations, and ability to collect antigen eliciting a positive response (p < 0.001). CONCLUSION: Antigen identification was successful for patients with 'active' disease. Antigens for which patients test positive on standard panels may not be present in their environment. One benefit to patient-centered testing is the ability to develop recommendations specific to their environment. As most individuals tested positive for >1 antigen, further investigation is warranted to determine the actual antigen responsible for disease.

Web based listing of agents associated with new onset work-related asthma.

BACKGROUND: Work-related asthma is common and yet remains a challenge to diagnose. Access to a listing of agents associated with work-related asthma has been suggested as useful in assisting in the diagnosis. METHODS: The Association of Occupational and Environmental Clinics (AOEC) developed criteria that were used to review the peer-reviewed medical literature published in English. Based on this review, substances were designated either as a sensitizing agent or an irritant. The reviews were conducted by a board certified internist/pulmonologist/occupational medicine specialist from 2002 to 2007 and a board certified internist/occupational medicine physician from 2008- date. All reviews were then reviewed by the nine member AOEC board of directors. RESULTS: The original list of agents associated with new onset work-related asthma was derived from the tables of a text book on work-related asthma. After 13 years of review, there are 327 substances designated as asthma agents on the AOEC list; 173 (52.9%) coded as sensitizers, 35 (10.7%) as generally recognized as an asthma causing agent, four (1.2%) as irritants, two (0.6%) as both a sensitizer and an irritant and 113(34.6%) agents that still need to be reviewed. CONCLUSIONS: The AOEC has developed a readily available web based listing of agents associated with new onset work-related asthma in adults. The listing is based on peer-reviewed criteria. The listing is updated twice a year. Regular review of the peer-reviewed medical literature is conducted to determine whether new substances should be added to the list. Clinicians should find the list useful when considering the diagnosis of work-related asthma.

HLA class II DPB1 and DRB1 polymorphisms associated with genetic susceptibility to beryllium toxicity.

OBJECTIVES: Chronic beryllium disease (CBD) is a hypersensitivity granulomatous pulmonary disease caused by exposure to the metal beryllium (Be²âº). Our objective was to extend current knowledge of the genetics of beryllium disease by examining all HLA-DPB1 and HLA-DPR1 gene polymorphisms and the interactions between them. METHODS: DNA-based typing of HLA-DPB1 and HLA-DRB1 loci at the allele level was performed on 65 CBD, 44 beryllium sensitised (BeS) but without CBD and 288 non-affected, beryllium exposed controls. RESULTS: The DPßE69 residue regardless of zygosity, but particularly if present on non-*0201 alleles, was of primary importance for the development of CBD and BeS, while other negatively charged residues DPßDE55, 56 and DPßDE84, 85 incrementally increased, although not independently, the risk. The DPßE69 positive alleles with charge -7 or -9 were associated with both CBD and BeS. The polymorphic residues DPßE69, DPßDE55, 56 and DPßDE84, 85 were responsible for the -9 charge and the first two residues for the -7 charge. CONCLUSIONS: In the absence of DPßE69, DRßE71 is a risk factor for CBD and BeS. DPßE69 and DRßE71 are adjacent to other amino acids that are also negatively charged, suggesting that the positively charged Be²âº modifies the local environment of the epitopes in a way that promotes interactions between peptides and T cells and results in CBD. Finally, the protective effect of the DPB1*0201 positive haplotype may involve particular polymorphisms outside of the DPB1 gene.

The Upper Midwest Health Study: a case-control study of primary intracranial gliomas in farm and rural residents.

Since several studies indicated that farmers and agricultural workers had an excess risk of brain cancer, the National Institute for Occupational Safety and Health initiated the Upper Midwest Health Study to examine risk of intracranial glioma in the non-metropolitan population. This population-based, case-control study evaluated associations between gliomas and rural and farm exposures among adults (ages 18 to 80) in four upper midwestern states (Iowa, Michigan, Minnesota, Wisconsin). At diagnosis/selection, participants lived in non-metropolitan counties where the largest population center had fewer than 250,000 residents. Cases were diagnosed 1 January 1995 through 31 January 1997. Over 90% of 873 eligible ascertained cases and over 70% of 1670 eligible controls consented to participate. Participants and nonparticipants, evaluated for "critical questions" on main and refusant questionnaires, differed significantly in farming and occupational experience, ethnicity, education, and lifestyle. The 1,175 controls were more likely than the 798 cases to have reported ever drinking alcohol (77% vs. 73%, adjusted odds ratio (OR) 0. 73, 95% confidence interval (CI) 0.59-0.92) and having had panoramic dental x-rays (34% vs. 29%, OR 0. 75, CI 0.61-0.92). Controls spent a greater percentage of their lives in non-metropolitan counties (78% vs. 75%, OR 0.81, CI 0.67-1.09). Among ever-farmers, controls were more likely to have had exposure to farm insecticides (57% vs. 50%, OR 0.75, CI 0.59-0.95) and farm animals (96% vs. 91%, OR 0.48, CI 0.25-0.90). Moving to a farm as an adolescent (ages 11 to 20) vs. as an adult was associated with a greater risk of glioma. In our study sample, farm or rural residence and summary farm exposures were associated with decreased glioma risk. However, nonparticipation by never-farming eligible controls could have affected results. Comparisons of farm chemical exposures may clarify associations between farming and glioma that others have reported.

A descriptive study of work aggravated asthma.

BACKGROUND AND AIMS: Work related asthma (WRA) is one of the most frequently reported occupational lung diseases in a number of industrialised countries. A better understanding of work aggravated asthma (WAA), as well as work related new onset asthma (NOA), is needed to aid in prevention efforts. METHODS: WAA and NOA in the United States were compared using cases reported to the National Institute for Occupational Safety and Health (NIOSH) from four state Sentinel Event Notification Systems for Occupational Risks (SENSOR) surveillance programmes for 1993-95. RESULTS: A total of 210 WAA cases and 891 NOA cases were reported. WAA cases reported mineral and inorganic dusts as the most common exposure agent, as opposed to NOA cases, in which diisocyanates were reported most frequently. A similar percentage of WAA and NOA cases still experienced breathing problems at the time of the interview or had visited a hospital or emergency room for work related breathing problems. NOA cases were twice as likely to have applied for workers' compensation compared with WAA cases. However, among those who had applied for worker compensation, approximately three-fourths of both WAA and NOA cases had received awards. The services and manufacturing industrial categories together accounted for the majority of both WAA (62%) and NOA (75%) cases. The risk of WAA, measured by average annual rate, was clearly the highest in the public administration (14.2 cases/10(5)) industrial category, while the risk of NOA was increased in both the manufacturing (3.2 cases/10(5)) and public administration (2.9 cases/10(5)) categories. CONCLUSIONS: WAA cases reported many of the same adverse consequences as NOA cases. Certain industries were identified as potential targets for prevention efforts based on either the number of cases or the risk of WAA and NOA.

Evaluation of the effectiveness of following up laboratory reports of elevated blood leads in adults.

The usefulness of a statewide laboratory-based blood lead surveillance system to initiate workplace enforcement inspections was studied. In particular, the effectiveness of inspection of companies in which at least one worker had a blood lead level (BLL) 30-39 microg/dL but no greater than 39 microg/dL was considered. The surveillance system identified all individuals who had been tested for blood lead. Adults with BLLs > or =30 microg/dL were interviewed. Companies where lead exposures occurred were identified and enforcement inspections performed there. Companies were grouped into four categories: one or more employees with BLL > or =50 microg/dL; one or more employees with highest BLL of 40-49 microg/dL; one or more employees with highest BLL of 30-39 microg/dL; and companies that used lead but from which no blood lead reports were received. The number of citations and amounts of penalties, and BLLs before and after, were compared among the three blood lead groups and with a control group of no lead-using companies. A cost-benefit analysis was performed. Citations and penalties did not differ among the three blood lead groups but were markedly increased compared with the lead using but no blood lead group. Violations of specific lead standard components were similar among the three blood lead groups. Blood lead companies had increased citations and penalties as compared with nonusing lead control companies. No significant decrease in blood leads was seen postinspection. Total cost to identify lead-exposed workers at problem work sites was $125 ($53-$459) per lead-exposed worker. Followup of companies identified through the surveillance system was an effective method to target workplace inspections. It is recommended that routine inspection be instituted for all companies in which an employee is reported to have a blood lead of 30 microg/dL or greater.

What is the most cost-effective way to identify silica problem worksites?

BACKGROUND: State based surveillance systems to identify cases of silicosis have been developed over the past 18 years to target worksite interventions to reduce the incidence of silicosis. Using data from the Michigan silicosis surveillance system, we conducted an analysis to determine the most cost-effective way to identify problem worksites. METHODS: The initial reporting source of all 470 confirmed cases of silicosis reported to the Michigan surveillance system from 1989 to 1995 was identified. The cost of identifying confirmed cases, worksites, problem worksites, silica problem worksites, and the number of current silica-exposed workers was determined for four reporting sources: hospitals; physicians; workers' compensations; and death certificates. RESULTS: Hospital reports were the first to identify 67% of the confirmed cases, 74% of the worksites, and 58% of the problem worksites. Physician reports initially identified 17% of confirmed cases, 15% of worksites, and 26% of problem worksites. Workers' compensation records initially identified 11% of confirmed cases, 4% of worksites, and 8% of problem worksites. Death certificates initially identified 5% of confirmed cases, 7% of worksites, and 8% of problem worksites. Hospital reports were the most cost-effective way to identify cases (US$ 143), worksites (US$ 313), and problem worksites (US$ 454). CONCLUSIONS: Hospital discharge records identified the greatest number of confirmed cases and problem worksites and was the most cost-effective approach to identify both individuals with silicosis and worksites with problems.

Kidney disease and silicosis.

AIM: To determine the prevalence of kidney disease in a cohort of individuals with silicosis. METHODS: Review of medical records and questionnaires from patients reported to a state surveillance system for silicosis. Reporting of individuals with silicosis is required by state law. All individuals with silicosis reported as required by law to the State of Michigan. Individuals included in this article were reported from 1987 to 1995. Cases were reported by hospitals, physicians, the state workers' compensation bureau, or from death certificates. Only individuals who met the criteria for silicosis developed by the National Institute for Occupational Safety and Health (NIOSH) were included. RESULTS: Medical records were reviewed of 583 individuals with confirmed silicosis. This was mainly a population of elderly men. Ten percent of the 583 silicotics were found to have some mention of chronic kidney disease, and 33% of the 283 silicotics who we had laboratory tests on had a serum creatinine level >1.5 mg/dl. An association between kidney disease and age and between kidney disease and race was found among this cohort of 583 silicotics. Individuals with silicosis were more likely to have a serum creatinine level >1.5 mg/dl than age- and race-matched controls. However, no relationship between duration of exposure to silica or profusion of scarring on chest X-ray and prevalence of kidney disease or elevated creatinine levels was found. CONCLUSIONS: This study confirms previous case reports and epidemiologic studies of end-stage renal disease that found an association between kidney disease and exposure to silica. The epidemiologic data are conflicting on the mechanism by which silica causes kidney disease and are compatible with silica being able to cause kidney disease by both an autoimmune and direct nephrotoxic effect. Chronic kidney disease should be considered as a complication of silicosis.

Why most workers with occupational repetitive trauma do not file for workers' compensation.

Despite the availability of no fault insurance for wage replacement and medical care costs, the majority of workers diagnosed with an occupational disease do not apply for workers' compensation. The objective of the study was to determine the reasons why workers diagnosed with work-related musculoskeletal disease did not apply for workers' compensation benefits. A cross-sectional study of 1598 individuals diagnosed with neck, upper extremity, and low back work-related musculoskeletal disease from April to June 1996 was performed. All individuals were interviewed over the telephone using a standardized questionnaire. The questionnaire included questions about the precipitating event; demographics; health limitations; mood; pain level; and attitudes toward their health care provider, fellow workers, management, work environment, and filing for workers' compensation. Whenever possible, standardized questions from previous surveys were used. The interviewed individuals with work-related musculoskeletal disease were reported by health care practitioners as required by the state of Michigan's occupational disease reporting law. Workers reported during 12 weeks in the spring of 1996 by a Michigan health care professional as having a neck, back, or upper extremity musculoskeletal disorder were eligible to participate. Among the 2703 reports received, 490 individuals could not be reached, 22 did not speak English, 12 had died or were too incapacitated by other medical conditions, and 581 refused. We interviewed 59% of all eligible workers and 73% of all workers who were reachable and capable of responding in English. Only 25% of workers diagnosed with musculoskeletal disease filed a workers' compensation claim. The factors significantly associated with filing a claim were (1) increased length of employment (> 21 years: odds ratio [OR], 3.01, 95% confidence interval [CI], 1.31 to 6.90); 11 to 20 years: OR, 2.34, 95% CI, 1.01 to 5.47; 6 to 10 years: OR, 1.76, 95% CI, 0.73 to 4.25; 1 to 5 years: OR, 2.36, 95% CI, 1.03 to 5.42; < 1 year: OR, 1.00; (2) lower annual income (< $40,000: OR, 1.75, 95% CI, 1.06 to 2.88 vs > or = $80,000: OR, 1.00); (3) workers' dissatisfaction with coworkers (OR, 1.76, 95% CI, 1.01 to 3.06); (4) physician restrictions on activity (OR, 2.16, 95% CI, 1.55 to 3.00); (5) type of physician providing treatment (specialist, including surgeon or orthopedist: OR, 3.63, 95% CI, 2.37 to 5.55); physical and occupational therapist: OR, 2.15, 95% CI, 1.35 to 3.43); family practitioner: OR, 1.33, 95% CI = 0.89 to 2.01; company physician: OR = 1.00); (6) off work > or = 7 days (OR, 14.85, 95% CI, 10.57 to 20.85); (7) decreased current health status (OR, 0.82, 95% CI, 0.70 to 0.96); and (8) increased severity of illness (OR, 1.24, 95% CI, 1.06 to 20.88). This study showed that only 25% of workers with a work-related musculoskeletal condition filed for workers' compensation and refutes the common perception that an individual with a work-related problem is likely to file a workers' compensation claim. The strongest predictors of who would file were those factors associated with the severity of the condition. Other factors were increasing length of employment, lower annual income, and worker dissatisfaction with coworkers. Our study population consisted mainly of unionized autoworkers, and our findings may not be generalizable to the total workforce.

Surveillance of work-related asthma in selected U.S. states using surveillance guidelines for state health departments--California, Massachusetts, Michigan, and New Jersey, 1993-1995.

PROBLEM/CONDITION: Cases of work-related asthma (WRA) are sentinel health events that indicate the need for preventive intervention. WRA includes new-onset asthma caused by workplace exposure to sensitizers or irritants and preexisting asthma exacerbated by workplace exposures. REPORTING PERIOD: This report reviews cases of WRA identified by state health departments from January 1, 1993, through December 31, 1995, as well as follow-up investigations of cases and associated workplaces conducted through June 30, 1998. DESCRIPTION OF THE SYSTEMS: State-based surveillance and intervention programs for WRA are conducted in California, Massachusetts, Michigan, and New Jersey as part of the Sentinel Event Notification Systems for Occupational Risks (SENSOR) cooperative agreement program, initiated by CDC's National Institute for Occupational Safety and Health (NIOSH). RESULTS: From 1993 through 1995, a total of 1,101 cases of WRA were identified by SENSOR surveillance staff members in California, Massachusetts, Michigan, and New Jersey. Of these 1,101 cases, 19.1% were classified as work-aggravated asthma, and 80.9% were classified as new-onset asthma. Objective evidence substantiating asthma work-relatedness was documented in the medical records of 3.4% of WRA cases identified in the two states (Michigan and New Jersey) where medical records are routinely reviewed for this information. Indoor air pollutants, dusts, cleaning materials, lubricants (e.g., metalworking fluids), and diisocyanates were among the most frequently reported causes of WRA. In addition, a well-recognized cause of occupational asthma - natural rubber latex - was identified in a new setting, the healthcare industry. The most common industries associated with WRA cases included transportation equipment manufacturing (19.3%), health services (14.2%), and educational services (8.7%). Air sampling for agents known to induce occupational asthma was performed in Michigan for comparison with established federal time-weighted average exposure limits. Sixteen (13.4%) of 119 workplaces tested had airborne concentrations exceeding NIOSH recommended exposure limits (RELs); 11 (9.1%) of 121 workplaces had concentrations exceeding permissible exposure limits (PELs) of the Michigan Occupational Safety and Health Act (MIOSHA) program. INTERPRETATION: The surveillance data findings confirm well-recognized causes of asthma and have identified new putative causes (e.g., cleaning materials and metalworking fluids). Because the surveillance program depends on physicians' recognizing asthma work-relatedness and reporting diagnosed cases, the data are considered an underestimate of the magnitude of the WRA problem. The data also indicate that physicians are not commonly performing objective physiologic tests to substantiate a WRA diagnosis. Workplace findings suggest a need to evaluate existing exposure standards for specific agents known to induce occupational asthma (e.g., diisocyanates). Case-based surveillance can help improve the recognition, control, and prevention of WRA. The SENSOR model also provides a mechanism for workers and physicians to request workplace investigations aimed at primary prevention for other workers. PUBLIC HEALTH ACTION: NIOSH and state health department representatives are working to establish a long-term agenda for state-based surveillance of work-related conditions and hazards. The results from the SENSOR WRA programs described in this report support inclusion of WRA as a priority condition warranting surveillance at the state level.

An evaluation of the incidence of work-related asthma in the United States.

The objective of the study was to estimate the incidences of physician-diagnosed cases of work-related asthma (WRA) in Michigan and the entire United States. The statewide surveillance system for WRA in Michigan receives reports primarily from three sources: physicians, hospital discharge data, and worker's compensation claims. Knowledge of the overlap in reports from these sources was used in conjunction with capture-recapture methods to estimate the total number of diagnosed cases of WRA, and incidence rates were calculated using the estimated number of civilian employees in Michigan as the population at risk. For the entire United States, the product of a national incidence rate for asthma among adults and estimates of the proportion that is work-related was used. A total of 933 cases of WRA were reported to the Michigan surveillance program during 1988-1995, of which 904 were reported by at least one of the three main sources and equaled an average incidence of 27 cases/10(6)/year. This estimate was less than the range of estimates 58 to 204 cases/10(6)/year in Michigan arrived at using the capture-recapture methods. The national estimates of WRA ranged from 63 to 441 cases/10(6)/year. The authors' indirect estimates are closer to estimates from Canada, Sweden, and Finland than most existing direct estimates in the United States, but probably still underestimates the magnitude of WRA incidence because of the limitations of physician recognition of the work-relatedness of asthma among adults.

Connective tissue disease and silicosis.

BACKGROUND: To determine the prevalence of connective tissue disease in a cohort of individuals with silicosis, we reviewed the medical records and questionnaires from individuals reported from 1987 to 1995 to a state surveillance system for silicosis. Reporting of individuals with silicosis is required by state law. Cases were reported by hospitals, physicians, the state workers' compensation bureau, or from death certificates. Only individuals who met the criteria for silicosis developed by the National Institute for Occupational Safety and Health (NIOSH) were included in the analysis. RESULTS: A questionnaire was completed for all 583 cases. Medical records were available for 463. There were 24 people with rheumatoid arthritis, one with scleroderma, and one with systemic lupus erythematosus. All were men. The prevalence of rheumatoid arthritis was 5.2% (relative risk (RR) 2.73, 95% confidence limit (CL) 1.75-4.06). The prevalence of scleroderma was 0.2% (RR 15.65, 95% CL 0.21-87.03) and the prevalence of systemic lupus erythematosus was 0.2% (RR 11.37, 95% CL 0.15-63.23). This is an approximately 2.5-15-fold increased risk for these connective tissue diseases compared to estimated prevalences in the general population. Individuals with silicosis and connective tissue disease did not differ from individuals with silicosis but without connective tissue disease by race, age, type of industry where exposed to silica, history of tuberculosis, whether or not they had applied for workers' compensation, and whether or not they had progressive massive fibrosis on chest x-ray. CONCLUSION: Although the association between scleroderma and silicosis has been more widely reported in the literature, the prevalence of rheumatoid arthritis was greater than the prevalence of scleroderma or systemic lupus erythematosus among a cohort of individuals with silicosis.

Occupational noise-induced hearing loss surveillance in Michigan.

Occupational noise-induced hearing loss (NIHL) is an important yet often overlooked illness that can affect an individual's safety and performance at work. This article describes a state-based surveillance system for occupational NIHL. The Michigan surveillance system enables us to describe the magnitude of occupational NIHL among Michigan workers and direct public health interventions in the form of enforcement workplace inspections. The data presented are based on interviews of individuals with occupational NIHL reported to the Michigan Department of Consumer and Industry Services (MDCIS) by Michigan's audiologists and otolaryngologists from 1992-1997. From 1992-1997, 1378 individuals with occupational NIHL were reported to the MDCIS and interviewed about their exposures to noise at work. Over 70% of the workplace noise exposure were in manufacturing. At the most recent company where these individuals were exposed to noise, approximately 46% were not provided regular hearing testing. Regular hearing testing was more likely to occur in the larger companies and in industries covered by regulations requiring such testing to be performed. There were improvements over time in the percentages of companies providing regular hearing testing and hearing protection. Construction workers are employees among a group of industries that are not adequately protected from excessive noise exposures by occupational regulations. Regular hearing testing was not provided for over 90% of construction jobs, although hearing protection such as earplugs or earmuffs was provided for approximately half of these jobs. Forty-three state enforcement inspections were conducted at the companies reported by the patients interviewed, because these companies were reported to provide no regular hearing testing or no hearing protection despite exposures to excessive levels of noise. During the 43 inspections, 23 companies had noise levels above dBA, and 17 of those had either no hearing conservation program (HCP) or had one that was cited as being incomplete. The inspections potentially protected 758 similarly exposed workers in the companies with the high noise levels that lacked an HCP or that had a deficient HCP. The number of patients with occupational NIHL is likely a gross underestimate of the true magnitude of the disease. However, the surveillance system has identified workplaces with hazardous levels of noise and no HCP, thereby protecting similarly exposed coworkers of the index patients from further exposures to noise and hearing loss.

Asbestos-related x-ray changes in foundry workers.

Michigan has a statewide mandatory occupational disease reporting system. As part of that system, reports are received from hospital, physicians, death certificates, the worker's compensation bureau, and company medical departments. Based on this reporting, the State of Michigan has a special emphasis program for the surveillance of silicosis, a known disease outcome among foundry workers. From 1985-1996, 115 cases reported to the State Surveillance System as silicosis, pneumoconiosis not specified, or pulmonary fibrosis were reclassified as having asbestos related x-ray changes after a B-reader interpretation of each case's chest x-ray. During this same period there were an additional 697 reports confirmed as silicosis and 6,724 cases reported to the surveillance system as asbestosis. Among the 115 reports reclassified as having asbestos-related x-ray changes without evidence of silicosis-related x-ray changes, 54 had worked in foundries. Only 7 (14.8%) of these individuals had their primary work in maintenance in the foundry; 40 (85.1%) had their primary foundry work in a production job; and for 10 individuals the occupation was not known. Asbestos has been used in foundries on pipe laggings, boiler coverings, as insulation in fan housings, in gloves, aprons and curtains, as insulation in cupolas, and in ladles and insulation in sand molds. Clinicians caring for foundry workers need to be aware that asbestos-related x-ray changes are not uncommon in this population and asbestos exposure should be considered as one of the carcinogens contributing to the known increased risk of lung cancer among foundry workers.

What percentage of workers with work-related illnesses receive workers' compensation benefits?

This study estimates the rate at which workers suffering from occupational illnesses file for workers' compensation lost wage benefits and identifies some of the factors that affect the probability that a worker with an occupational illness will file. A database of reports of known or suspected cases of occupational illness is matched with workers' compensation claims data. Overall, between 9% and 45% of reported workers file for benefits. Data limitations prevent a more precise estimate of this rate, but a large proportion of workers with occupational illnesses clearly does not utilize the worker's compensation system. Logit analysis of a choice-based sample shows that women and employees of small firms are more likely than others to file for worker's compensation and that filing rates vary considerably across industries and diagnostic categories. Acute conditions related to the current job are no more likely to lead to claims than chronic conditions with long latency periods between exposure and development of disease.

Work-related asthma and respiratory symptoms among workers exposed to metal-working fluids.

The objective of this work was to determine whether the prevalence of respiratory symptoms differed among workers exposed to different types of metal-working fluids. As part of a mandatory surveillance system for occupational illness, from 1988-1994, the Michigan Department of Public Health received, 86 occupational disease reports of work-related asthma secondary to exposure to metal-working fluids. As part of a public health program, follow-up industrial hygiene inspections, including medical interviews of the workforce, were performed at companies where the reported cases had become ill. Metal-working fluids were the second most common cause of work-related asthma reported in the state. Most of the reports were from the automobile industry. Follow-up inspections were conducted at 37 facilities where the individuals with work-related asthma had worked. Seven hundred and fifty-five workers at these facilities were interviewed. Only one facility was above the allowable oil mist standard. Despite the exposure levels being within the legal limits, approximately 20% of the fellow workers of the reported cases had daily or weekly respiratory symptoms suggestive of work-related asthma. Workers exposed to emulsified, semisynthetic, or synthetic machining coolants were more likely to have chronic bronchitis; to have visited a doctor for shortness of breath; to have visited a doctor for a sinus problem; to be bothered at work by nasal stuffiness, runny nose, or sore throat; and to have an increased prevalence of respiratory symptoms consistent with work-related asthma, compared to workers exposed to mineral oil metal-working fluids. These findings were found in individuals who currently smoked, had never smoked or were ex-cigarette smokers. Further research to determine the chemical components or microbial contaminants responsible for these findings is needed.

A state-based surveillance system for work-related asthma.

The current national surveillance system for occupational illnesses underestimates the incidence of work-related asthma. This article describes a state-based surveillance system for work-related asthma. The Michigan surveillance system enables us to estimate the incidence of work-related asthma, describe the characteristics of affected individuals, and facilitate public health interventions in the form of workplace inspections. The data presented are based on interviews with a case-series of individuals with work-related asthma reported to the Michigan Department of Public Health (MDPH) from 1988 to 1994. We also present cross-sectional data on coworkers of the index cases, who were interviewed during the workplace investigations, and exposure measurements from those investigations. Potential cases were reported by physicians, hospitals, or the Michigan Department of Labor. Case eligibility was based on the criteria for work-related asthma developed by the National Institute for Occupational Safety and Health (NIOSH). Between 1988 and 1994, 725 people who met the NIOSH criteria for work-related asthma were reported to the MDPH. Seventy-six percent of the reports were from physicians, 17.1% were from hospitals, 7.3% were from workers' compensation records, and 3.5% were from other health professionals. Eighty-three percent of the reports were for individuals with the onset of newly diagnosed asthma after a period of symptomless exposure, 7.3% were for aggravation of preexisting asthma, and 9.5% were for reactive airway dysfunction syndrome (RADS). The overall annual average incidence rate of work-related asthma in Michigan was 2.9 cases per 100,000 workers. Rates were 0.8/100,000 in the service industry and 8.5/100,000 in manufacturing. Isocyanates and machining coolants were the two most common causes of asthma among workers reported to the surveillance system. Demographics of the individuals reported are described. During workplace follow-up investigations, 861 fellow workers were identified as having possible work-related asthma. Another 151 coworkers were identified from the company-maintained injury and illness logs as having possible work-related asthma. In addition, the investigations identified two new causes of work-related asthma. The primary limitations of the surveillance system include a lack of objective testing to confirm the diagnosis of work-related asthma and underreporting of cases. Despite these limitations, this state-based surveillance system has proven successful in identifying new cause of asthma and identifying workplaces with a high prevalence of workers with respiratory symptoms who may benefit from public health interventions.