Biomedical subjects

M Gérin

Publications and source records attributed to M Gérin.

At least 19 recordsLinked to original sources

PubMed2006

Monte Carlo simulation to reconstruct formaldehyde exposure levels from summary parameters reported in the literature.

OBJECTIVES: This study presents a procedure allowing the numerical synthesis of exposure data reported in different ways in the literature, including summary parameters and single measurements. The procedure was applied to literature regarding formaldehyde exposure in the reconstituted wood panels industry, including oriented-strand board (OSB), medium density fibre board (MDF) and particle board (PB). METHODS: For each publication providing summary parameters we estimated geometric means (GM) and geometric standard deviations (GSD) by assuming lognormality of exposure levels. Monte Carlo simulation was performed to re-create datasets from the sample sizes and estimated GMs and GSDs, allowing their subsequent formatting together with the single measurements. The precision and bias of the methods used to estimate GMs and GSDs were evaluated. RESULTS: Altogether, the 13 articles included in our study yielded a final database of 874 data, of which 732 were simulated. For both area and personal data, exposures corresponding to MDF and PB were similar while OSB levels were lower. The most recent available personal levels (1985-1994) were highest in PB for jobs performed in the vicinity of the press (GM=0.63 mg m-3). Corresponding area levels were highest for PB in the main production zone (GM=0.43 mg m-3). Mixed-effects models fitted to area PB data explained 38% of the total variability. A 6-fold decrease in exposures from 1965 to 1995 was estimated. Replication of the simulation process yielded relative standard deviations of the calculated GMs and GSDs between 10 and 20%. The relative biases of the methods used to estimate GMs and GSDs varied across methods and decreased with higher sample sizes (from approximately 15% for n=5 to less than 5% for n=30, in absolute value). The precision also varied across methods and improved with higher sample sizes (from approximately 30% for n=5 to approximately 10% for n=30). DISCUSSION: This methodology constitutes a new meta-analysis tool that should improve the interpretation of industrial hygiene literature data, but needs to be further validated.

Air Pollutants, Occupational↗

PubMed2002

[Ocular involvement during primary central nervous system lymphoma].

PURPOSE: The aim of our study was to assess and to characterize the ocular involvement in patients with primary central nervous system lymphoma. POPULATION AND METHODS: We conducted a prospective study between August 1995 and December 1998 on a cohort of consecutive patients affected by primary central nervous system lymphoma and who underwent a systematic ophthalmological examination before treatment. RESULTS: The study population comprised 24 patients (mean age, 57 years; 16 women and 8 men). Among these patients, 6 had ocular involvement (2 patients with ocular signs revealing the cerebral process, 2 evidenced at the time of the initial ocular examination, and 1 as the disease evolved). Ocular involvement was vitritis in all cases, anterior uveitis in 1 patient, obliterant vasculitis in 1 patient and yellowish subretinal lesions in 1 patient. In 1 case, a vitrectomy led to adequate diagnosis of the disease. CONCLUSION: Our study shows a 25% incidence of ocular involvement in patients with primary central nervous system lymphoma, with posterior uveitis as the most common manifestation. Because of the relatively high incidence of ocular involvement, a systematic ophthalmological examination of this subset of patients should be mandatory.

Adult↗

PubMed2001

[A full thickness macular hole as an uncommon complication of Behçet disease].

The authors report the occurrence of an unusual complication of Behçet's disease: a full thickness macular hole caused by retinal vasculitis resulting in a definite functional impairment. A review of the different ocular complications is provided, stressing the unusual location on the posterior segment and the potential seriousness of these complications.

Adrenal Cortex Hormones↗

PubMed2000

Laryngeal and hypopharyngeal cancers and occupational exposure to formaldehyde and various dusts: a case-control study in France.

OBJECTIVES: A case-control study was conducted in France to assess possible associations between occupational exposures and squamous cell carcinomas of the larynx and hypopharynx. METHODS: The study was restricted to men, and included 201 hypopharyngeal cancers, 296 laryngeal cancers, and 296 controls (patients with other tumour sites). Detailed information on smoking, alcohol consumption, and lifetime occupational history was collected. Occupational exposure to seven substances (formaldehyde, leather dust, wood dust, flour dust, coal dust, silica dust, and textile dust) was assessed with a job exposure matrix. Exposure variables used in the analysis were probability, duration, and cumulative level of exposure. Odds ratios (ORs) with their 95% confidence intervals (95% CIs) were estimated by unconditional logistic regression, and were adjusted for major confounding factors (age, smoking, alcohol, and when relevant other occupational exposures). RESULTS: Hypopharyngeal cancer was found to be associated with exposure to coal dust (OR 2.31, 95% CI 1.21 to 4.40), with a significant rise in risk with probability (p<0.005 for trend) and level (p<0.007 for trend) of exposure. Exposure to coal dust was also associated with an increased risk of laryngeal cancer (OR 1.67, 95% CI 0.92 to 3.02), but no dose-response pattern was found. A significant relation, limited to hypopharyngeal cancer, was found with the probability of exposure to formaldehyde (p<0.005 for trend), with a fourfold risk for the highest category (OR 3.78, 95% CI 1.50 to 9.49). When subjects exposed to formaldehyde with a low probability were excluded, the risk also increased with duration (p<0.04) and cumulative level of exposure (p<0.14). No significant association was found for any other substance. CONCLUSION: These results indicate that exposure to formaldehyde and coal dust may increase the risk of hypopharyngeal cancer.

Aged↗

PubMed1999

Sinonasal cancer, occupation, and tobacco smoking in European women and men.

BACKGROUND: In this analysis of European case-control studies on sinonasal cancer, we examined the risk for occupation and smoking, by gender and histological type. METHODS: The pooled data included 104 female and 451 male cases, and 241 female and 1,464 male controls. Lifetime smoking and occupational history were recoded following uniform criteria, and job-exposure matrices were applied for wood and leather dust. RESULTS: Wood dust exposure was associated with an excess risk in men (OR = 2.36, 95% CI 1.75-3.2) but not in women (OR = 1.17, 95% CI 0.31-4.47). Exposure to leather dust was associated with an excess risk in both genders. Both wood and leather dust were associated with adenocarcinomas rather than squamous cell carcinomas. Excess risks for smoking were higher for squamous cell carcinomas and higher in men than in women. CONCLUSIONS: In these European populations, occupation was associated with about 11% of all sinonasal cancers in women and 39% in men. This difference can, in part, be attributed to variation in exposure patterns between genders.

Adenocarcinoma↗

PubMed1998

Associations between several sites of cancer and occupational exposure to benzene, toluene, xylene, and styrene: results of a case-control study in Montreal.

BACKGROUND: Except for the leukemogenic effects of benzene, there is inadequate or sparse evidence on the carcinogenicity of the most common monocyclic aromatic hydrocarbons. The purpose of this study was to generate hypotheses on associations between exposure to benzene, toluene, xylene, and styrene and various common types of cancer. METHODS: In the context of a population-based case-control study carried out in Montreal, 3,730 cancer patients (15 types of cancers, not including leukemia) and 533 population controls were interviewed, and their job histories were translated by a team of experts into occupational exposures, including benzene, toluene, xylene, and styrene. In the present analysis, exposure to these substances was compared between each case series and a control group pooling selected cancer patients and population controls, using logistic regression analysis. RESULTS: Exposure levels were low for most exposed subjects, and there was a high correlation between exposure to benzene, toluene and xylene. For most sites of cancer there was no evidence of excess risk due to these substances. However, limited evidence of increased risk was found for the following associations: esophagus-toluene, colon-xylene, rectum-toluene, rectum-xylene and rectum-styrene. CONCLUSIONS: These latter observations warrant further investigation.

Adult↗

PubMed1997

Sinonasal cancer and occupation. Results from the reanalysis of twelve case-control studies.

A pooled reanalysis of twelve case-control studies on sinonasal cancer and occupation from seven countries was conducted in order to study associations with occupations other than wood- and leather-related occupations. The pooled data set included a total of 930 cases (680 men and 250 women) and 3,136 controls (2,349 men and 787 women). All the studies included a detailed occupational history for cases and controls. Each job was coded using the same classifications for occupation and industry. Two approaches were used in the analysis: systematic analysis of occupations; a priori analysis using a preestablished list of occupations and industries. The results confirmed associations observed in several studies not included in this analysis. For agricultural workers, significant excesses were observed for squamous cell carcinoma among women (OR = 1.69) and men (OR = 3.72 for ten years or more of employment as an orchard worker), and adenocarcinomas among men (OR = 2.98 for ten years or more of employment). Associations with textile occupations were observed for adenocarcinoma among women (OR = 2.60) and squamous cell carcinoma among men (OR = 5.09 for fiber preparers, 3.01 for bleachers). Elevated risks for both histologic types were observed among men employed in food manufacturing (OR = 3.25, adenocarcinoma), or as food preservers (OR = 13.9, squamous cell carcinoma), and among men employed as cooks (OR = 1.99, squamous cell carcinoma). A positive association with squamous cell carcinoma was observed for male transport equipment operators (OR = 1.21), and also with adenocarcinoma for male motor-vehicle drivers (OR = 2.50). A number of other associations were observed in the systematic analysis.

Adenocarcinoma↗

PubMed1997

Reliability of an expert rating procedure for retrospective assessment of occupational exposures in community-based case-control studies.

The most daunting problem in community-based studies of occupational cancer is retrospective exposure assessment. To avoid the error involved in using job title as the exposure variable or self-report of exposure, our team developed an approach based on expert judgment applied to job descriptions obtained by interviewers. A population-based case-control study of cancer and occupation was carried out in Montreal between 1979 and 1986, and over 4,000 job histories were assessed by our team of experts. The job histories of these subjects were evaluated, by consensus, by a team of chemist/hygienists for evidence of exposure to a list of 294 workplace chemicals. In order to evaluate the reliability of this exposure assessment procedure, four years after the rating was completed, we selected 50 job histories at random and had two members of the expert team carry out the same type of coding, blind to the original ratings for these jobs. For 25 job histories, comprising 94 distinct jobs, the pair worked as a consensus panel; for the other 25, comprising 92 distinct jobs, they worked independently. Statistical comparisons were made between the new ratings and the old. Among those rated by consensus, the marginal distribution of exposure prevalence was almost identical between old and new. The weighted kappa for agreement was 0.80. Among items for which both ratings agreed that there had been exposure, there was good agreement on the frequency, concentration, and route of contact. When the two raters worked independently, the levels of agreement between them and between each of them and the original rating was good (kappas around 0.70), though not as high as when they worked together. It is concluded that high levels of reliability are attainable for retrospective exposure assessment by experts.

Adult↗

PubMed1997

Sinonasal cancer and occupational exposure to textile dust.

Data from a case-control study conducted at 27 hospitals in France in 1986-88 were analyzed to examine the association between exposure to textile dust and sinonasal cancer. The study included 207 cases and 409 controls. Detailed information on occupational history and other potential risk factors for sinonasal cancer was collected. Exposure to textile dust (probability and level of exposure, type of textile fiber) was assessed by an expert in industrial hygiene. Among women, exposure to textile dust was associated with an elevated risk of squamous cell carcinoma (odds ratio (OR) = 2.45, 95% confidence interval (CI) = 0.85-7.06, nine exposed cases) and adenocarcinoma (OR = 3.70, 95% CI = 0.56-24.4, three exposed cases). For squamous cell carcinomas, the risk increased with the duration and the level of exposure (P < 0.05): the ORs for the low, medium, and high level of cumulative exposure were 1.00 (95% CI = 0.10-9.43), 2.43 (95% CI = 0.54-11.1), and 3.57 (95% CI = 0.92-13.8), respectively. There was also a limited evidence of an excess risk of squamous cell carcinomas among men exposed to high levels of textile dust (OR = 2.18, 95% CI = 0.65-7.30, four exposed cases). Because of the strong association between wood-dust exposure and adenocarcinoma, an independent effect of textile dust on this type of cancer could not be studied among men. The risks associated with the different types of textile fibers (cotton, wool, and synthetic fibers) were similar and the results did not permit to incriminate a particular type of textile.

Adenocarcinoma↗

PubMed1997

A study of ethylene glycol exposure and kidney function of aircraft de-icing workers.

Ethylene glycol levels were measured in 154 breathing zone air samples and in 117 urine samples of 33 aviation workers exposed to de-icing fluid (basket operators, de-icing truck drivers, leads and coordinators) studied during 42 worker-days over a winter period of 2 months at a Montreal airport. Ethylene glycol as vapour did not exceed 22 mg/m3 (mean duration of samples 50 min). Mist was quantified at higher levels in 3 samples concerning 1 coordinator and 2 basket operators (76-190 mg/m3, 45-118 min). In 16 cases workers' post-shift or next-morning urine contained quantities of ethylene glycol exceeding 5 mmol/mol creatinine (up to 129 mmol/mol creatinine), with most of these instances occurring in basket operators and coordinators, some of whom did not wear paper masks and/or were accidentally sprayed with de-icing fluid. Diethylene glycol was also found in a few air and urinary samples at levels around one tenth those of ethylene glycol. Urinary concentrations of albumin, beta-N-acetyl-glucosaminidase, beta-2-microglobulin and retinol-binding protein were measured and compared over various periods, according to subgroups based on exposure level and according to the frequency of extreme values. These analyses did not demonstrate acute or chronic kidney damage that could be attributed to working in the presence of ethylene glycol. In conclusion, this study does not suggest important health effects of exposure to de-icing fluid in this group of workers. Potential for overexposure exists, however, in certain work situations, and recommendations on preventive measures are given. In addition, these results suggest that other routes of absorption than inhalation, such as the percutaneous route, may be important and that urinary ethylene glycol may be a useful indicator of exposure to ethylene glycol.

Acetylglucosaminidase↗

PubMed1996

Occupational risk factors for prostate cancer: results from a case-control study in Montréal, Québec, Canada.

A population-based case-control study of cancer and occupation was carried out in Montréal, Canada. Between 1979 and 1986, 449 pathologically confirmed cases of prostate cancer were interviewed, as well as 1,550 cancer controls and 533 population controls. Job histories were evaluated by a team of chemist/hygienists using a checklist of 294 workplace chemicals. After preliminary evaluation, 17 occupations, 11 industries, and 27 substances were selected for multivariate logistic regression analyses to estimate the odds ratio between each occupational circumstance and prostate cancer with control for potential confounders. There was moderate support for risk due to the following occupations: electrical power workers, water transport workers, aircraft fabricators, metal product fabricators, structural metal erectors, and railway transport workers. The following substances exhibited moderately strong associations: metallic dust, liquid fuel combustion products, lubricating oils and greases, and polyaromatic hydrocarbons from coal. While the population attributable risk, estimated at between 12% and 21% for these occupational exposures, may be an overestimate due to our method of analysis, even if the true attributable fraction were in the range of 5-10%, this represents an important public health issue.

Adult↗

PubMed1995

Wood dust and sino-nasal cancer: pooled reanalysis of twelve case-control studies.

In order to examine the relationship between wood dust and sino-nasal cancer, data from 12 case-control studies conducted in seven countries were pooled and reanalyzed. The relative risks associated with wood-related jobs and with exposure to wood dust, measured using a job exposure matrix based on occupation and industry titles, were examined using logistic regression. The combined data set consisted of 680 male cases, 2,349 male controls, 250 female cases, and 787 female controls. A high risk of adenocarcinoma among men was associated with employment in wood-related occupations (odds ratio [OR] = 13.5, 95% confidence interval [CI] = 9.0-20.0) and the risk was greatest among men who had been employed in jobs with the highest wood dust exposure (OR = 45.5, 95% CI = 28.3-72.9) and increased with duration of exposure. The risk of adenocarcinoma also appeared elevated among women employed in wood-related jobs (OR = 2.5, 95% CI = 0.5-12.3), but the small number of exposed cases precluded detailed analysis. Women in wood dust-exposed jobs appeared to have an excess of squamous cell carcinoma (OR = 2.1, 95% CI = 0.8-5.5) which increased with duration of exposure. An increased risk of squamous cell carcinoma in men was seen only among those employed for 30 or more years in jobs with exposure to fresh wood (OR = 2.4, 95% CI = 1.1-5.0). The results of this analysis provide strong support to the association between exposure to wood dust in a variety of occupations and the risk of sino-nasal adenocarcinoma and are consistent with the results of individual participating studies, although the magnitude of the excess risk varied. The evidence in regard to squamous cell carcinomas was ambiguous and there was a great deal of heterogeneity observed in individual study results. This may be due to differences in risk associated with exposure to hardwoods and softwoods or with other, as yet to be identified, aspects of exposure.

Adenocarcinoma↗

PubMed1995

Cancer risk due to occupational exposure to polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) demonstrate carcinogenic activity in animal models. Although some epidemiologic studies have implicated PAHs as risk factors for human cancer, the evidence reported to date has not been consistent. The purpose of this report is to describe the associations between occupational exposure to PAHs in the workplace and each of 14 types of cancer. A population-based, case-control study was carried out in Montreal to investigate associations between a large variety of environmental and occupational exposures on the one hand, and several types of cancer on the other. A detailed job history was obtained from each subject along with information on a number of potential confounders. Each job history was reviewed by a team of experts, who used this information to construct a corresponding history of occupational exposures. Among the PAH exposures considered were benzo(a)pyrene (B(a)P) and five categories of PAHs defined on the basis of the source material, namely, wood, petroleum, coal, other sources, and any source. Altogether, 3,730 cancer patients and 533 population controls were interviewed and their job exposure histories coded. For each of 14 types of cancer analyzed, three control groups were available: other cancer patients, population controls, and the pooled set of cancer and population controls. The associations between 14 cancer types and 6 PAH exposures were analyzed using logistic regression methods. For most types of cancer evaluated, there was no evidence of excess risk due to PAHs at the levels encountered in the occupations in which PAH exposure has been prevalent in the Montreal area. For a few cancer sites--the esophagus, the pancreas, and the prostate gland--there were suggestions of excess risk; these observations are noteworthy hypotheses for further investigation. For lung cancer, there appeared to be an increased risk due to PAHs among nonsmokers and light smokers, but not among heavy smokers.

Adult↗

PubMed1994

Occupational risk factors for bladder cancer: results from a case-control study in Montreal, Quebec, Canada.

A population-based case-control study of the associations between various cancers and occupational exposures was carried out in Montreal, Quebec, Canada. Between 1979 and 1986, 484 persons with pathologically confirmed cases of bladder cancer and 1,879 controls with cancers at other sites were interviewed, as was a series of 533 population controls. The job histories of these subjects were evaluated by a team of chemist/hygienists for evidence of exposure to a list of 294 workplace chemicals, and information on relevant non-occupational confounders was obtained. On the basis of results of preliminary analyses and literature review, 19 occupations, 11 industries, and 23 substances were selected for in-depth multivariate analysis. Logistic regression analyses were carried out to estimate the odds ratio between each of these occupational circumstances and bladder cancer. There was weak evidence that the following substances may be risk factors for bladder cancer: natural gas combustion products, aromatic amines, cadmium compounds, photographic products, acrylic fibers, polyethylene, titanium dioxide, and chlorine. Among the substances evaluated which showed no evidence of an association were benzo(a)pyrene, leather dust, and formaldehyde. Several occupations and industries were associated with bladder cancer, including motor vehicle drivers and textile dyers.

Adult↗

PubMed1994

Sinonasal cancer and wood dust exposure: results from a case-control study.

A case-control study of occupational risk factors for sinonasal cancer was conducted in France in 1986-1988. The study included 207 histologically confirmed cases and 409 controls. Among the male cases were 59 men with squamous cell carcinoma and 82 with adenocarcinoma. The risk of sinonasal cancer in relation to wood dust exposure was studied in these two groups. The analysis was based on a case-by-case assessment of exposure by an industrial hygienist. Hardwood and softwood were distinguished. An approximate twofold increase in risk for squamous cell carcinomas was observed for cases whose first exposure to either hardwood or softwood occurred before 1945; however, the two types of exposure were highly correlated. An exposure to wood dust--from either hardwood alone or hardwood and other kinds of wood--was found for all but two of the 82 male cases with adenocarcinoma. The effects of different elements of exposure to hardwood (duration, level, period) were studied in detail with a logistic model. Two components of exposure--duration and average level--contributed independently to the overall very elevated risk. Additional exposure to wood other than hardwood did not increase the risk.

Adenocarcinoma↗

PubMed1994

Occupational and environmental exposure of garage workers and taxi drivers to airborne manganese arising from the use of methylcyclopentadienyl manganese tricarbonyl in unleaded gasoline.

Occupational and environmental exposure to airborne manganese has been measured for two groups of workers in Montreal, taxi drivers and garage mechanics. In Canada methylcyclopentadienyl manganese tricarbonyl (MMT) has replaced lead as an anti-knock agent in gasoline and represents a potentially important source of manganese contamination for the population in general and for the two chosen groups of workers in particular. Twenty workers (10 taxi drivers and 10 garage mechanics) wore a personal air sampler for five consecutive working days and two off-work periods. The amount of total Mn on each filter was determined by neutron activation analysis and then converted to atmospheric Mn concentrations. The values obtained varied from 0.004 microgram m-3 to 2.067 micrograms m-3. At work the garage mechanics were exposed to an average of 0.250 microgram m-3 and the taxi drivers to 0.024 microgram m-3. Off-work, the two groups were exposed respectively to an average of 0.007 microgram m-3 and 0.011 microgram m-3. In the garages there was twice as much Mn in the air on days when the doors were closed compared to days when they were left opened (0.314 micrograms m-3/0.152 microgram m-3). The levels found in this study remain well below the established limits for occupational and environmental airborne exposure. These results will lead to further studies to positively identify the source of Mn as MMT and to explore other pathways leading to the contamination of the general population.

Air Pollutants↗

PubMed1993

Sinonasal cancer and occupational exposure to formaldehyde and other substances.

A case-control study of cancer of the nose and paranasal sinuses was conducted in France to determine whether occupational exposure to formaldehyde was associated with an increased risk of sinonasal cancer. Exposures to 14 other substances or groups of substances were also studied (wood dust, leather dust, textile dust, flour dust, sugar dust, coal/coke dust, nickel compounds, chromium compounds, chromium VI, welding fumes, soldering fumes, cutting oils, paints and lacquers, glues and adhesives). Cases (n = 207) and controls (n = 409) were interviewed to obtain detailed information on job history and other potential risk factors for sinonasal cancer. In addition, a questionnaire specially designed for this study was used to help assess exposures to formaldehyde and other substances of interest. The questionnaires were translated into history of occupational exposure by an expert in industrial hygiene, without knowledge of case-control status. Several exposure variables (lifetime average level, duration, cumulative level) were used to describe the risk related to exposure to formaldehyde. Potential confounding factors (occupational and non-occupational) were examined and adjusted for when necessary. No significant association was found between exposure to formaldehyde and squamous-cell carcinomas of the sinonasal cavities. Because of the strong association between exposure to wood dust and nasal adenocarcinoma, it was not possible to assess an independent effect of formaldehyde on this type of cancer. However, among males exposed to medium or high levels of wood dust, the risk of adenocarcinoma associated with formaldehyde was significantly elevated for the highest exposure categories for average level (OR = 5.3, 95% confidence interval = 1.3-22.2), cumulative level (OR = 6.9, 95% CI = 1.7-28.2) and duration of exposure (OR = 6.9, 95% CI = 1.7-27.8). Although a residual confounding effect of wood dust could not be excluded, this study suggests that exposure to both formaldehyde and wood dust may increase the risk of nasal adenocarcinoma, by comparison with the risk due to wood dust alone. This study also indicated an increased risk among males who had been exposed to glues and adhesives, for all histologic types, which was not explained by a confounding effect of paints and lacquers, wood dust or formaldehyde. No other significant association was observed.

Adenocarcinoma↗

PubMed1993

Job exposure matrices in industry.

Job exposure matrices (JEM) are designed to link information on occupation with information on exposure to specific workplace hazards. In spite of some limitations, JEM are particularly useful in large retrospective epidemiological studies. The development of JEM designed for a company or an industrial sector have a more specific field of application than JEM used in population-based studies, and can therefore be based on a more detailed classification of occupations and better exposure information. This article reviews on-going research related to the design of JEM in support of industry-based studies. The review covers design aspects related to the structure of JEM, and specially the four main axes that may produce differences on exposure characteristics: agent (exposure), job, time and place. Attention has also been given to the different sources of information on exposure, the characteristics of the exposure and the validation of exposure estimates.

Data Collection↗