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Biomedical subjects

G M Liss

Publications and source records attributed to G M Liss.

At least 37 records · Page 2Linked to original sources
PubMed1998

Incidence of latex sensitization among latex glove users.

BACKGROUND: Although there are several reports of the prevalence of latex sensitization among health care workers, the incidence of sensitization is unknown. OBJECTIVE: The objective of this study was to estimate the incidence of sensitization among latex glove users at a hospital in Hamilton, Ontario, Canada. METHODS: Workers with negative results to the skin test at baseline were followed prospectively over 1 year, some wearing powdered gloves and others using powder-free gloves. They were reevaluated in 1995 with a questionnaire and skin prick test (SPT) sensitivity to latex reagents, three common inhalants, and six foods. A conversion was defined as a (new) latex SPT with wheal diameter at least 4 mm greater than saline control. Glove extracts were assayed for antigenic protein, and air samples were obtained to estimate exposure to airborne latex protein. RESULTS: During powdered glove use, personal exposures ranged from 5 to 616 ng/m3, whereas during powder-free glove use, all but two results for air samples were below the limit of detection (about 0.1 ng/m3). During the study period, the protein concentration in the powdered gloves, initially mean 557 microg/gm of sample, declined at a rate of 295 microg/gm per year (p < 0.0001). Of the 1075 SPT-negative participants at baseline, 479 were working in eligible wards, and of these, 435 (91%) participated in follow-up, 227 using powder-free gloves and 208 using powdered gloves. We identified four conversions, two (1.0%) in the powdered glove group and two (0.9%) in the powder-free group. The two participants using powdered gloves were the only converters who were symptomatic. The significance of skin test conversions identified in the powder-free group, both asymptomatic patients, is unclear. The limitations of the study are discussed, including the limited power, the declines in latex protein concentrations, and the possibility of information (observer) bias. CONCLUSION: To our knowledge, this represents the first reported estimate (about 1%) of incidence of sensitization in hospital personnel using latex gloves.

Cross-Sectional Studies↗
PubMed1997

Hospital records: an underutilized source of information regarding occupational diseases and exposures.

A 1993 study examined the association between pneumoconiosis and cor pulmonale using a computerized data base of hospital records in Ontario (Hospital Medical Records Institute, HMRI). The present investigation was undertaken to confirm the coding of the diagnoses of a subset of the hospital discharges from that study, to determine the validity of the coding of the diagnoses of coal workers' pneumoconiosis (CWP), and to identify work exposure (occupation and industry) information available in hospital records. We sent abstraction forms to hospitals for 521 subjects who were hospitalized for pneumoconiosis, cor pulmonale, or both conditions, requesting information regarding diagnoses, occupation and industry data, and X-ray results. Abstracts were received for 720 (76%) of 944 discharges that were sought. The hospital abstractions confirmed the HMRI coding for 90% of the charts with these conditions, including 63%, 97%, and 96% discharges for CWP, silicosis, and asbestosis, respectively. Specific dust exposures were indicated in 42% of the charts with a code indicating a diagnosis of CWP, and of these, 67% indicated exposure to coal dust. Of charts with a code indicating a diagnosis of silicosis, 73% with specific dust information indicated silica exposure, and 95% of those for asbestosis indicated exposure to asbestos. Of 34 individuals in this data set known from the Ministry of Labour's Chest Clinic X-ray Surveillance Program of miners to have silicosis, 33 (97%) were diagnosed by the hospitals as having pneumoconiosis, and all but two were silicosis. Hospital records, as reflected by HMRI data, are reliable indicators of cor pulmonale and pneumoconiosis. The agreement with the Chest Clinic's X-ray diagnoses provides additional objective confirmation of the accuracy of the hospital information. There were relatively few cases of silicosis miscoded as CWP. At least for pneumoconioses, hospital records contained information about the exposures that led to these diseases in approximately 50% of the cases. However, whether hospital records would prove useful for detecting other work-related conditions that are not pathognomonic of occupation is not known. The importance of taking occupational histories needs continued emphasis in medical education and training.

Asbestosis↗
PubMed1997

Assessment of the relationship between isocyanate exposure levels and occupational asthma.

As part of a previous study, we identified Ontario cases of isocyanate-induced occupational asthma (OA) and the companies at which they worked. The Ontario Ministry of Labour maintained a computerized database including isocyanate air sampling determinations conducted by the Ministry. Within this database, we compared levels of isocyanate concentrations measured at 20 case companies [with compensated isocyanate asthma (OA) claims] with 203 noncase companies, based on air samples collected during the same 4-year period during which the OA claims arose. The proportion of case companies that were ever recorded as having a measured ambient isocyanate concentration of > or = 0.005 ppm was greater than that for noncase companies, for TDI users (43% vs 22%), and for MDI users (40% vs 27%). This reached conventional significance when combined across companies and isocyanate types (50% vs 25%; P < 0.05). This provides some evidence that facilities having OA claims have higher isocyanate exposures than do those without claims.

Air Pollutants↗
PubMed1997

Latex allergy: epidemiological study of 1351 hospital workers.

OBJECTIVE: To determine the prevalence of latex sensitisation among a large group of healthcare workers, study the occupational and non-occupational factors associated with latex allergy, and characterise latex exposure in air and by gloves. METHODS: All 2062 employees of a general hospital in Hamilton, Ontario, Canada who regularly used latex gloves were invited to participate in a cross sectional survey, representing the baseline phase of a prospective cohort morbidity study. Attempts were made to recruit employees who were diagnosed with latex allergy before the survey. Glove extracts were assayed for antigenic protein, and area and personal air samples were obtained on two occasions (summer and winter) to estimate exposure to airborne latex protein. A questionnaire on medical and occupational information was administered by an interviewer. Skin prick tests were performed with latex reagents, three common inhalants, and six foods. RESULTS: The mean (SD) latex protein concentrations were 324 (227) micrograms/g in powdered surgical gloves and 198 (104) micrograms/g in powdered examination gloves. Personal latex aeroallergen concentrations ranged from 5 to 616 ng/m3. There was a total of 1351 (66%) participants. The prevalence of positive latex skin tests was 12.1% (95% confidence interval (95% CI) 10.3% to 13.9%). This prevalence did not vary by sex, age, hospital, or smoking status but subjects who were latex positive were significantly more likely to be atopic (P < 0.01). Participants who were latex positive were also significantly more likely to have positive skin tests to one or more foods (Mantel-Haenszel odds ratio (OR) adjusted for atopy 12.1, 95% CI 7.6 to 19.6, P < 10(-9)). Work related symptoms were more often reported among latex positive people, and included hives (OR 6.3, 95% CI 3.2 to 12.5), eye symptoms (OR 1.9, 95% CI 1.2 to 2.8), and wheezy or whistling chest (OR 4.7, 95% CI 2.8 to 7.9). The prevalence of latex sensitivity was highest among laboratory workers (16.9%), and nurses and physicians (13.3%). When the glove consumption per healthcare worker for each department was grouped into tertiles, the prevalence of latex skin test positivity was greater in the higher tertiles of glove use for sterile (surgical) gloves (P < 0.005) but not for examination gloves. CONCLUSIONS: In this large, cross sectional study of healthcare workers, the prevalence of latex sensitisation was 12.1% (9.5% among all those eligible), and there were significant associations with atopy, positive skin tests to certain foods, work related symptoms, and departmental use of gloves per healthcare worker. This cohort is being followed up prospectively and will be retested to determine the incidence of development of latex sensitivity.

Adult↗
PubMed1996

Can Dupuytren's contracture be work-related?: review of the evidence.

Dupuytren's contracture (DC) is a disease of the palmar fascia resulting in thickening and contracture of fibrous bands on the palmar surface of the hands and fingers. For decades, a controversy has existed regarding whether acute traumatic injury or cumulative biomechanical work exposure can contribute to the development of this disorder. To address this controversy, this review considers the following questions: Is there evidence that DC is associated with 1) frequent or repetitive manual work; and 2) hand vibration? The published literature was searched for studies meeting the following criteria: 1) in English or having an English abstract; 2) controlled studies; 3) DC an identified health outcome studied; and 4) the study group exposed to repetitive or frequent manual work, vibration, or acute traumatic injury. Relevant non-English articles identified through English abstracts were translated. The validity of studies meeting the selection criteria was assessed using a series of questions adapted from those of Stock [1991: Am J Ind Med 19:87-107]. Studies that met a priori minimum levels of methodologic quality were taken into account to reach conclusions with respect to the above questions. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each study. Ten studies met the initial selection criteria. Of these, four studies met the criteria for methodologic quality, one addressing the relationship between manual work and DC, and three studies of vibration and DC. No controlled studies of acute trauma and DC were identified. Bennett [1982: Br J Ind Med 39:98-100] found the prevalence of DC at a British PVC bagging and packing plant in which workers were exposed to repetitive manual work to be 5.5 times that at a local plant without packing, and twice the expected prevalence in a U.K. working population previously studied by Early [1962: J Bone Joint Surg 44B:602-613]. DC was observed more frequently among vibration white finger claimants than controls by Thomas and Clarke [1992: J Soc Occup Med 42:155-158] (OR, 2.1; 95% CI, 1.1-3-9), and more frequently among vibration-exposed workers than controls by Bovenzi et al. [1994: Occup Environ Med 51:603-611] (OR, 2.6 95% CI, 1.2-5.5). Cocco et al [1987: Med Lav 78:386-392] found that a history of vibration exposure occurred more frequently among cases of DC than among controls (OR, 2.3; 95% CI, 1.5-4.4). The latter two studies presented some evidence of a dose-response relationship. There is good support for an association between vibration exposure and DC.

Causality↗
PubMed1996

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).

Adolescent↗
PubMed1996

Latex allergy can induce clinical reactions to specific foods.

OBJECTIVE: The purpose of this study was to investigate crossreactivity between latex and foods, to identify crossreacting IgE binding proteins, and to assess the clinical significance. METHODS: Forty-seven latex allergic patients and 46 non-latex allergic patient controls were studied. Allergen sensitization was determined by skin-prick testing (SPT) and allergenic proteins were identified by immunoblot reactivity and amino acid sequence analysis. RESULTS: Immunological reactivity to foods was found to be common, occurring in 33 latex-allergic individuals but in only seven controls (P < 0.000001); 100 of 376 (27%) food skin-prick tests were positive in the latex-allergic subjects. Twenty-seven out of 100 positive food SPTs were associated with clinical symptoms. Seventeen patients manifested a clinical allergy to at least one food including 11 with anaphylaxis, and 14 with local sensitivity reactions. Positive food skin tests occurred most frequently with avocado (53%), potato (40%), banana (38%), tomato (28%), chestnut (28%), and kiwi (17%). Latex-allergic patients (23%) recognize a protein that had sequence homology to a broad class of plant proteins known as patatins. Crossreactivity between latex and several potato proteins was observed by immunoblot inhibition analysis. CONCLUSIONS: Sensitization to latex has extensive crossreactivity with certain foods and leads to clinical allergic reactions. Potatoes and tomatoes are newly reported cross-reacting foods. Plant proteins with structural homology to latex proteins may predispose to food allergy.

Adolescent↗
PubMed1995

Musculoskeletal problems among Ontario dental hygienists.

Two U.S. surveys suggested that dental hygienists (DHs) may suffer from carpal tunnel syndrome (CTS), but these studies did not use validated questionnaires, adjust for confounders, or include external controls. We conducted a questionnaire survey of all 2,142 DHs belonging to the Ontario Dental Hygienists' Association, and a referent group of 305 dental assistants (DAs), who do not scale teeth. The Standardized Nordic Questionnaire was used as the basis for asking about musculoskeletal symptoms. The response rates in the two groups were identical. Of the DHs, 7.0% had been told by a physician since starting work that they had CTS, but only 1 of 65 had received workers' compensation. Compared to the DAs, after adjusting for age the DHs were 5.2 times (95% confidence interval [CI] 0.9-32) more likely to have been told they had CTS and 3.7 times (95% CI 1.1-11.9) more likely to meet a CTS case definition. The DHs were also 2.5 (95% CI 1.6-3.9), 2.8 (95% CI 1.8-4.4), and 1.8 (95% CI 1.2-2.7) times more likely to report hand/wrist, shoulder, and neck problems in the past 12 months, respectively, but were less likely to report low back trouble. In internal analyses among DHs using logistic regression models, the number of heavy calculus patients per day, "clock" position around the dental chair, and years in practice were significant predictors of CTS. Days worked per week (but not heavy calculus patients), time with the trunk rotated, and years of practice were significant predictors of reported shoulder trouble in the past 12 months. Given that there are more than 9,000 DHs in Canada and about 100,000 in the United States, these findings suggest an important public health problem. They highlight the need to inform DHs during training and continuing education about musculoskeletal problems in general and CTS in particular. Attention should be directed to areas such as work station design, posture, treating patients with heavy calculus, and scheduling rest periods.

Adult↗
PubMed1994

Toxic health effects including reversible macrothrombocytosis in workers exposed to asphalt fumes.

We investigated an outbreak of irritative and neurotoxic symptoms associated with exposure to asphalt fumes in a commercial lighting factory; 27 symptomatic female workers were clinically assessed including hematologic testing. When compared with a laboratory reference group (n = 107), the workers' mean platelet volume (MPV) was significantly higher and mean platelet count was lower (p = 0.013 and p = 0.048, respectively). Five months later, the factory's ventilation system was substantially modified. Follow-up assessments 6 months postmodification on 15 of the original workers documented a significant decline in acute symptoms and a lowering of the subjects' mean MPV towards normal (p = 0.0007 by paired t-test). The findings suggest that reversible macrothrombocytosis (enlarged platelets) can occur among symptomatic workers exposed to asphalt fumes.

Adult↗
PubMed1994

Follow-up of a group of workers intoxicated with 4,4'-methylenedianiline.

4,4'-Methylenedianiline (MDA), an aromatic amine, is a known human hepatotoxin and an animal carcinogen but there is little information regarding its chronic effects in humans. Between 1967 and 1976, 10 workers at a plant in Ontario that used MDA as an epoxy hardener developed acute jaundice. We followed this group from the date of intoxication through to the end of 1991 for cancer incidence by matching with the Ontario Cancer Registry. To date, one cancer, a pathologically confirmed bladder cancer has developed (expected number based on provincial incidence rates: 0.64 for all cancers, 0.05 for bladder cancer). This finding may be important because bladder cancer was a site of interest a priori; bladder cancers have been observed in two other occupationally exposed groups (significantly higher than expected in one of these); in the National Toxicology Program bioassay, urinary bladder tumors occurred in exposed animals but not in controls; and MDA has structural similarity to known human bladder carcinogens such as benzidine.

Acute Disease↗
PubMed1994

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.

Data Collection↗
PubMed1993

Cor pulmonale and pneumoconiotic lung disease: an investigation using hospital discharge data.

Cor pulmonale has been reported in the past to be associated with pneumoconiosis as an end-stage complication. However, whether the association can be demonstrated among cases of pneumoconiosis acquired in more recent decades is not clear. We examined the relation between these conditions using data summarized in hospital records in Ontario for males discharged between 1979 and 1990 with a diagnosis of chronic cor pulmonale or one of the pneumoconioses. Based on the age-specific frequency rates, cor pulmonale was diagnosed 17 (95% confidence interval 13-22) times more frequently than expected among men diagnosed with pneumoconiosis than among other men admitted to hospital. Our investigation indicates that cor pulmonale still appears to be associated with dust exposure in the workplace, and it demonstrates the usefulness of hospital discharge information in addressing questions in occupational health. However, we recommend that hospital medical records be examined to confirm the diagnoses and to determine the smoking histories of these men.

Adult↗
PubMed1993

Assessment of risk factors for IgE-mediated sensitization to tetrachlorophthalic anhydride.

Two groups of workers with occupational asthma caused by tetrachlorophthalic anhydride (TCPA) have been reported on; in only one report was specific anti-TCPA antibody demonstrated. We received a request to investigate respiratory problems among workers at a plant where solenoid coils are manufactured with the use of epoxy resin and where a new TCPA hardener had been introduced in 1988. In response, we conducted a cross-sectional evaluation of 52 current workers and assayed serum samples from 49 workers for TCPA-human serum albumin-specific IgE and IgG by ELISA. Mean airborne TCPA concentrations ranged from 0.21 to 0.39 mg/m3 in 1989 and May 1990 but were considerably lower (less than 0.009 to 0.13 mg/m3) by July 1990 when ventilation was introduced. Workers were classified in four departments as molders (most directly working with TCPA), those intermittently exposed to TCPA, coil assemblers, and office workers. There was a high prevalence of reported work-related respiratory symptoms (from 27% to 39%). The mean decline in FEV1 over the shift in the molders (down 4.1%) was significantly different from the change in the office group (increased 2.5%). Intrashift change in FEV1 was inversely correlated with log personal TCPA concentration (r = -0.47). Of 49 current workers, 15 (31%) had elevated serum TCPA-human serum albumin-specific IgE antibody levels and 19 (39%) had elevated specific IgG levels. The prevalence of specific IgE was highest in the mold and intermittent groups (54%), in comparison with the coil assembly (25%) and office (0%) groups. Those workers who were IgE positive were significantly less likely to be current smokers and had worked significantly longer since 1988. Of those hired in 1988 or after, the proportion of workers who were IgE positive increased with duration of employment category (p value for trend 0.022). Since ventilation was installed and TCPA exposures reduced to less than 0.1 mg/m3, there has been a marked decrease in symptoms and no new cases of occupational asthma among newly hired workers at the plant.

Adult↗