Comparison of clinic models for patients with work-related asthma.

BACKGROUND: Work-related asthma (WRA) is a prevalent occupational lung disease that is associated with undesirable effects on psychological status, quality of life (QoL), workplace activity and socioeconomic status. Previous studies have also indicated that clinic structure may impact outcomes among patients with asthma. AIMS: To identify the impact of clinic structure on psychological status, QoL, workplace limitations and socioeconomic status of patients with WRA among two different tertiary clinic models. METHODS: We performed a cross-sectional analysis between two tertiary clinics: clinic 1 had a traditional referral base and clinical staffing while clinic 2 entirely comprised Worker's Compensation System referrals and included an occupational hygienist and a return-to-work coordinator. Beck Anxiety and Depression II Inventories (BAI and BDI-II), Marks' Asthma Quality of Life Questionnaire (M-AQLQ) and Work Limitation Questionnaire (WLQ) were used to assess outcomes for patients with WRA. RESULTS: Clinic 2 participants had a better psychological status across the four instruments compared with clinic 1 (for Beck 'Anxiety': P < 0.001 and 'Depression': P < 0.01, 'Mood' domain of M-AQLQ: NS and 'Mental Demands' domain of WLQ: P < 0.01). Clinic 2 had a greater proportion of participants with reduced income. CONCLUSIONS: Our study indicates that clinic structure may play a role in outcomes. Future research should examine this in larger sample sizes.

Work-exacerbated asthma in a workers' compensation population.

BACKGROUND: Asthma is becoming more prevalent with large numbers of individuals suffering from work-exacerbated asthma. AIMS: To examine the characteristics of workplace exposures and working days lost in relation to work-exacerbated asthma (WEA) in a workers' compensation population. METHODS: An analysis of accepted workers' compensation asthma claims in Ontario over a 5-year period. Claims among the top three industry groups were categorized based on working time lost of 1 day or less, 2-5 days and 6 days or more. Attributable agents were subdivided into dusts, smoke, chemicals and sensitizers. RESULTS: Among the asthma claims, 72% (645) fulfilled criteria for WEA from their history. The commonest industry groups were services, education and health care, with 270 claims that met our analysis requirements. Within these industry groups, education had a lower proportion of workers with short exacerbations (missing 1 day or less: 27%) while the health care industry had a higher than expected proportion of short exacerbations (55%). The agents to which WEA was attributed differed across the groups, with dusts having the highest proportion in the education group (65%), smoke in the service industry (34%) and sensitizers in health care (41%). Those agents more commonly attributed to exacerbations tended to have lower rates of prolonged exacerbation compared with less commonly involved agents. CONCLUSIONS: The morbidity of WEA and the type of agents to which it was attributed varied between industry groups.

Occupational contact allergens: are they also associated with occupational asthma?

BACKGROUND: Workplace exposures that can potentially cause both allergic occupational contact dermatitis (AOCD) and occupational asthma (OA) are not clearly identified. METHODS: Occupational contact allergens (OCAs) were identified using North American Contact Dermatitis Group (NACDG) data. Reference documents and systematic reviews were used to determine whether each OCA had been reported to potentially cause OA. The presence or absence of a sensitizer notation in occupational hygiene reference documents was also examined. RESULTS: The 10 most common OCAs were: epoxy resin*, thiuram, carba mix, nickel sulfate*, cobalt chloride*, potassium dichromate*, glyceryl thioglycolate, p-phenylenediamine*, formaldehyde* and glutaraldehyde*. Seven (indicated by *) were determined to be possible causes of OA. Information on sensitizing potential from OH reference materials contained conflicting information. CONCLUSIONS: Several common OCAs can also potentially cause OA. Inhalation and dermal exposures to these agents should be controlled and both OA and AOCD should be considered as possible health outcomes. Increased consistency in sensitizer notations is needed.

Symptoms after mould exposure including Stachybotrys chartarum, and comparison with darkroom disease.

BACKGROUND: Mould-attributed symptoms have included features which overlap with unexplained syndromes such as sick building syndrome. OBJECTIVES: We describe questionnaire and chart review findings in patients following exposure to moulds which include Stachybotrys and compare responses with two control groups. METHODS: Thirty-two patients presented with symptoms attributed to mould exposures. Exposure identification for 25 patients had reported S tachybotrys chartarum as well as other mould (Aspergillus, Penicillium), 88% at work. The remaining seven had professionally visualized or self-reported/photographic exposure evidence only. A chart review was performed and a follow-up with a questionnaire, including questions on current health status, and nonspecific symptoms. RESULTS: Cough, shortness of breath and chest tightness (at presentation) were reported in 79%, 70% and 64%, respectively, and persisted >6 weeks in 91%. Skin test(s) were positive to fungal extract(s) in 30%. Seventeen returned questionnaires were obtained 3.1 (SD 0.5) years after the initial clinic assessment. Among this subgroup, persisting asthma-like symptoms and symptoms suggestive of sick building syndrome were frequent, and similar to a group previously assessed for darkroom disease among medical radiation technologists. The mould-exposed group more commonly reported they were bothered when walking in a room with carpets, complained of a chemical or metallic taste in their mouth, and had problems in concentration when compared with a control physiotherapist group (P < 0.005). CONCLUSIONS: Although only a minority with health concerns from indoor mould exposure had demonstrable mould-allergy, a significant proportion had asthma-like symptoms. Other symptoms were also common and persistent after the initial implicated exposure.

Use of serum bile acids in the identification of vinyl chloride hepatotoxicity.

Most previous studies proposing serum bile acids as indicators of hepatic function have been performed in hospitalized patients in whom overt symptomatic liver disease was present. The ability of fasting levels of serum bile acids to identify mild, clinically inapparent chemical liver injury in an occupational setting was compared with that of indocyanine green clearance and routine biochemical liver tests in 67 asymptomatic chemical workers in whom liver biopsies had been performed for medical indications. Histologically, 15 were found to have chemical liver injury, 27 had nonchemical liver disease, and 25 were normal. Two serum bile acids, cholylglycine and conjugates of cholic acid, were determined by radioimmunoassay, using 466 "normal" males from the same worker cohort as a reference range. The geometric mean concentrations of cholylglycine in patients with chemical liver injury, patients with nonchemical liver disease, and normal subjects were 47.9, 19.1, and 20.0 micrograms/dl, respectively (p = 0.036 by analysis of variance). Conjugates of cholic acid showed similar differences (p = 0.027), as did indocyanine green clearance with mean half-life of 4.2, 3.2, and 3.3 minutes in the three biopsy subgroups, respectively (p = 0.043). Such differences were not observed for biochemical liver tests. The fasting level of serum bile acids provided high specificity but lower sensitivity in the detection of all types of liver disease. However, serum bile acids and indocyanine green clearance provided a higher specificity and sensitivity for chemical liver injury than for nonchemical liver disease. An index of average exposure to vinyl chloride was significantly greater in the subgroup with chemical liver injury than in the other two groups, further supporting the association of chemical type injury with impaired anion uptake. These data identify the fasting level of serum bile acids as a clinically usable indicator of early chemical injury in chemically exposed asymptomatic worker populations with liver dysfunction. Further investigation is needed in other occupational hepatotoxic environments to determine if this association is limited to vinyl monomer type injury.

Peak expiratory flow rates in possible occupational asthma.

Objective criteria for interpretation of peak expiratory flow rate readings were assessed in 50 patients evaluated for suspected occupational asthma who had at least two weeks of PEFR readings and an objective diagnosis based on other investigations. The prevalence of OA was 36 percent. Peak flows were interpreted by two observers blinded to other results. Criteria for a PEFR interpretation of OA were as follow: diurnal variation greater than or equal to 20 percent relatively more frequently or with greater variation on working days than days off work. With the objective diagnoses as the gold standard, the sensitivity of the PEFR interpretations was 72 percent for OA; specificity for no asthma was 53 percent. Excluding those with greater than or equal to 20 percent variation on only one day sensitivity improved to 93 percent for OA, and specificity to 77 percent. There was an acceptable level of interobserver variation (kappa 62 to 83 percent). We conclude that simple objective criteria for PEFR interpretation can be developed with acceptable interobserver variation.

Tuberculosis infection among staff at a Canadian community hospital.

OBJECTIVE: To determine risks for tuberculin skin-test conversion among employees of a community hospital in Ontario, Canada. DESIGN: Cohort morbidity study. SETTING: Of 14 metropolitan Toronto area hospitals surveyed for data on tuberculin skin-test conversions, only one provided tuberculosis (TB) test data on all employees. Between 1991 and June 1994, 24 patients were treated at this hospital for pulmonary TB. POPULATION STUDIED: The population at risk included those on staff from January 1991 through December 1993 who previously were skin-test negative; they were followed until the end of June 1994. Exposure was estimated (a) based on ranking departments according to an estimate of the number of hours of direct patient contact during a typical day, and (b) based on location of sputum-positive patients. OUTCOME MEASURE: Risks of skin-test conversion among hospital employees with documented prior negative skin tests. MAIN RESULTS: A total of 809 skin-test negative employees were followed for 2,084 person-years; 18 employees with skin-test conversions were identified. The overall conversion rate was 0.9% per year (0.86 per 100 person-years). After excluding two conversions attributed to contact with coworkers, the relative risk of conversion was 4.5 (5.5 after adjusting for age and gender) among those in the highest exposure category (> or = 4 hours per day), compared to those in departments ranked as having the lowest exposure (< 2 hours per day). Among those working in wards in which sputum-positive patients were treated, 2.4% converted; the risk of conversion was over six times greater than among those working on wards with no TB patients or in departments with no patient contact, of whom 0.4% converted. Among the emergency room staff, the department in which the greatest number of sputum-positive patients were treated, at least 5% of staff converted. In those instances in which conversions were associated with exposure to a specific TB patient, the involved patients had been in the hospital for at least 4 days prior to being isolated. CONCLUSIONS: These results indicate that even in a hospital with few admissions due to tuberculosis, skin-test conversions associated with occupational exposure may occur (Infect Control Hosp Epidemiol 1996; 17:29-35).

Urine phthalate determinations as an index of occupational exposure to phthalic anhydride and di(2-ethylhexyl)phthalate.

Although it has been estimated that over 600 000 workers in the United States are exposed to di(2-ethylhexyl)phthalate (DEHP), an animal carcinogen, and that over 100 000 are exposed to phthalic anhydride (PA), few data are available on levels of phthalates in biological fluids of these workers. For a determination of occupational exposure to PA and DEHP at a plant manufacturing DEHP from PA and 2-ethylhexanol, air samples were taken for PA and DEHP, and pre- and postshift urine samples were collected for the determination of total phthalates. Urine samples were obtained from 48 workers in jobs with high exposure to phthalates and from 47 workers in jobs with low exposure. The airborne concentrations of DEHP ranged from 20 to 4 110 micrograms/m3, and the concentrations of PA ranged from 4 to 203 micrograms/m3. The most heavily exposed workers had the highest mean postshift urine phthalate concentration (geometric mean 7.6 nmol/ml) (p = 0.015), and also the greatest mean increase (4.4 nmol/ml) in preshift to postshift urine phthalate levels. Twofold increases over the shift in urine phthalate concentration and postshift phthalate levels of greater than 10 nmol/ml were observed in 8 (25%) of 32 chemical operators, but in none of 52 other workers. These data suggest that measurement of urine phthalate levels may have utility for monitoring the exposure of workers manufacturing or using PA.

Homicide in the workplace in Ontario: occupations at risk and limitations of existing data sources.

This study has identified workplace homicides in Ontario from 1975 to 1985, described those at risk, and examined what existing data sources are most suitable for locating the occurrence of these events. Homicides were identified from two sources: the Office of the Chief Coroner and the Ontario Mortality Database (OMDB). Of the 84 homicides identified, 87% occurred among males; the average annual work-related homicide rate was 0.17 per 100,000 workers, with a male-to-female ratio of 5.2:1. The rates in males were about one-eighth of those reported in California and Texas. The highest rates occurred among policemen, gas station attendants, security guards, and taxi drivers, and in restaurants and in certain retail operations such as jewelry stores. These homicides represented about 4% of all traumatic workplace fatalities. Firearms were responsible for 56% of these homicides and the motive was robbery in 50%. The OMDB proved to be an awkward source from which to identify such deaths because there is no "injury-at-work" field on death certificates. Other existing sources of data were not able to locate work-related homicides. Guidelines to protect those at high risk of assault and homicide should be developed.

Improper office disposal of needles and other sharps: an occupational hazard outside of health care institutions.

An employee of a private disposal company suffered a finger needlestick injury while collecting waste at curbside from a building containing medical offices. Subsequent inspection of the contents of the garbage bags revealed the presence of used syringes and unsheathed needles. The Ministry of the Environment has developed a regulation and guidelines for the handling and disposal of biomedical waste including needles and other sharps. These specify that approved carriers and receivers are required for disposal; properly decontaminated waste is considered non-hazardous solid waste and can go to landfills. However, responsibility for curbside pickup of waste lies with municipalities; some municipalities have enacted by-laws which prohibit collection of this waste at the curbside. This incident illustrates that improper disposal of biomedical waste (including that from private practitioners' offices) may occur despite efforts to control its handling, and that needlestick injuries can occur outside of health care facilities among personnel who are not health care workers. Efforts are needed to increase the level of awareness among health professionals regarding their responsibility to ensure proper biomedical waste disposal from private offices. In addition, efforts should be made to bridge the gap between all levels of government regarding the disposal of biomedical waste.

Occupational exposure to Mycobacterium bovis infection in deer and elk in Ontario.

In late 1991, two herds of deer and elk were depopulated at a slaughtering plant in Ontario, followed by processing of infected animals at a rendering plant. We conducted a questionnaire plus tuberculin skin-test survey of 104 exposed slaughtering and rendering plant workers, and government veterinarians and inspectors. Overall, 17 participants were skin-test positive, one of 51 initially skin-test negative subjects tested a second time three months later became positive, consistent with the risk associated with occupational exposure during the depopulation of tuberculous elk previously observed in Alberta. Deer farming is widespread, with 263 herds in Ontario. The likely route of transmission is through aerosols. Possible reasons for the low conversion rate include the use of respiratory protection, absence of a tanning plant, an enclosed rendering plant process, and late skin testing which may have underestimated the number of conversions. Recommendations for prevention are summarized; in particular, respiratory protection for work with infected herds should probably include high efficiency particulate face masks.

Mortality among workers exposed to carbon disulfide.

Mortality experience was investigated at a plant in Ontario that produced viscose rayon, with carbon disulfide as a main raw material. Work-history records for 279 deceased workers at the plant (plant A) were obtained and compared with those for 511 deceased workers at a pulp and paper plant in the same city (plant B). In a proportional mortality analysis, using as a reference the general population of Ontario, at both plants there were fewer deaths from ischemic heart disease than expected (the proportional mortality ratios [PMRs] were 83 at plant A and 95 at plant B) but more deaths than expected from cerebrovascular disease (PMRs were 115 at plant A and 149 at plant B). In a subgroup of plant A workers who had been employed in high-carbon-disulfide exposure areas, deaths from ischemic heart disease were less than expected (PMR = 82), particularly among those who worked in these areas for more than 5 y. Most deaths occurred among those aged 65 y or more. Mortality from strokes, however, was greater than expected (PMR = 207, p < .05); the excess was confined to workers who died at age 65 y or older (PMR = 229, p = .01). Proportional mortality from strokes was also increased in the pulp workers among those who died at age 65 y or older (PMR = 153). In a case-control analysis, the risk of ischemic heart disease at plant A was slightly less than at plant B (odds ratio (OR] = 0.92, 95% confidence interval [CI] = 0.60-1.42), with no association between risk and years worked in high-carbon-disulfide areas (OR/y = 0.99, 95% CI = 0.94-1.03). Among those who died at age 65 y or older, the risk of stroke in the high-exposure subgroup was (a) increased significantly, compared with other plant A workers (OR = 4.92, 95% CI = 1.66-14.65); and (b) increased slightly, compared with plant B workers (OR = 1.37, 95% CI = 0.83-2.26). These results suggested an unusually low risk of strokes among other plant A workers. The risk of stroke was associated with years in high-carbon-disulfide areas (OR/y = 1.03, 95% CI = 0.96-1.1 0). The observed increase in proportional mortality from strokes may represent a chance finding, but a causal role for exposure cannot be excluded.

Occupational asthma in a home pieceworker.

A 67-yr-old woman presented to a free-standing medical center with respiratory distress of 1 day's duration. She was found on evaluation to have asthma associated with "dipping" the ends of polyurethane-coated wire into molten solder in the production, in her home, of components for the electronics industry. This process has been known to result in the evolution of isocyanates. The patient's sister had also developed cough and wheeze after she performed similar home piecework. Neither the manufacturer nor the distributors of the wire had provided a warning of its potential respiratory hazards. This episode emphasizes the importance of the occupational history, and of following-back thoroughly on cases of occupational disease. In addition, this episode reminds us that home pieceworkers are unlikely to have benefit of advice from industrial hygienists or others skilled in recognizing potentially hazardous situations.

Peripheral sensory neuropathy associated with 1,1,1-trichloroethane.

A case is described of peripheral sensory neuropathy in a woman who had daily exposure to 1,1,1-trichloroethane, used as a degreasing agent. Although previous reviews of the health effects of 1,1,1-trichloroethane have not indicated long-term neurotoxicity, there are recent animal studies that suggest chronic central neurotoxic effects and previous case reports of peripheral neuropathy in three exposed workers in one plant. Our case provides additional evidence that 1,1,1-trichloroethane exposure may be associated with peripheral sensory neuropathy. Reporting of similar cases is encouraged and investigation of the neurotoxic effects of 1,1,1-trichloroethane is recommended.

Injuries due to violence: workers' compensation claims among nurses in Ontario.

1. From 1987 to 1989 in Ontario, Canada, there were 100 or more allowed workers' compensation claims among nurses for injuries due to violence. The annual rates for such claims were higher among male nurses (13.9 per 1000) than among female nurses (1.4 per 1000). 2. Compared to the general Ontario work force, the rates for such claims were significantly higher among both male and female nurses. 3. These compensation data are consistent with surveys showing that nurses and other health care workers are at risk for violent injury in the workplace. 4. The compensation data likely underestimate the extent of the problem, because no statistics are available for denied claims or claims with no lost time, and many assaults are unreported. Measures for prevention and increasing awareness are required.