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Biomedical subjects

D Hémon

Publications and source records attributed to D Hémon.

At least 37 records · Page 2Linked to original sources
PubMed1999

GSTM1, smoking and lung cancer: a case-control study.

BACKGROUND: We conducted a case-control study to examine the risk of lung cancer in relation to GSTM1 polymorphism and cigarette smoking (primarily of black tobacco) in a French population. METHODS: The 611 subjects were 301 incident lung cancer cases and 310 hospital controls. We were able to constitute a DNA bank for 547 subjects (89.5%) and gather detailed information on smoking history for all of them. Results presented here concern 247 cases and 254 controls. RESULTS: Taking non- or light smokers as the reference category, we estimated odds ratios (OR) of 4.2 (95% CI: 2.6-6.7) and 5.2 (95% CI: 3.3-8.3) for the medium and heavy smokers respectively. On the other hand we estimated that the crude OR associating GSTM1 with lung cancer was 1.3 (95% CI: 0.9-1.8). Furthermore our data do not depart significantly from a multiplicative model of the combined effects of smoking and GSTM1 deficiency. CONCLUSIONS: We conclude that smoking and the GSTM1 gene are each a risk factor for lung cancer, and that their combined effect does not differ significantly from that of a multiplicative model.

Adult↗
PubMed1998

Occupational exposure to solvents and hairy cell leukaemia.

OBJECTIVES: The role of occupational exposures in hairy cell leukaemia was investigated through a multicentre, hospital based, case-control study. This paper analyses the role of exposure to solvents other than benzene in hairy cell leukaemia. METHODS: The study included 226 male cases and 425 matched controls, exposure to solvents was evaluated by expert case by case review of the detailed data on occupational exposures generated by specific interviews. Also, exposure to solvents was evaluated with an independently constructed job exposure matrix (JEM). RESULTS: No association was found between hairy cell leukaemia and previous employment in a job exposed to solvents (odds ratio (OR) 0.9 95% confidence interval (95% CI) 0.6 to 1.3). ORs for the main occupational tasks exposed to solvents were around 1 and did not increase with the frequency or the duration of the tasks. No specific type of paint or glue was found to be significantly associated with hairy cell leukaemia. No association was found with exposure to solvents, taken as a whole, with either expert assessments or the JEM. No association was found with aromatic, chlorinated, or oxygenated subgroups of solvents. The ORs did not increase with the average intensity of exposure assessed by the experts, with the frequency of use, or with the duration of exposure. Finally, no association was found with non-occupational exposure to solvents. CONCLUSIONS: The study did not show any association between exposure to solvents and hairy cell leukaemia.

Case-Control Studies↗
PubMed1998

Immunologic and renal markers among photogravure printers exposed to toluene.

OBJECTIVES: This study assessed immunologic and early renal effects of chronic toluene exposure. METHODS: In a longitudinal study of 92 printers and 74 referents, 145 subjects had pre- and poststudy samples of blood and urine taken for the following measurements: immunoglobulin E (IgE), antiglomerular basement membrane (anti-GBM) and antilaminin (anti-LAM) antibodies in blood; creatinine and beta2-microglobulin in blood and urine; and microalbumin, N-acetyl-b-D-glucosaminidase (NAG) and alanine-aminopeptidase in urine. Creatinine clearance was calculated according to the Cockroft-Gault formula. Eight-hour personal air samples were collected twice to assess present exposure to toluene. A job-exposure matrix was developed to estimate past cumulative exposure. Information about potential confounders was recorded by questionnaire. Multiple regression analysis was performed to study dose-effect relations adjusted for age and smoking. RESULTS: No subject was positive for anti-GBM antibodies, and only 12 were positive for anti-LAM. No relation was observed between the markers studied and present exposure to toluene except that creatinine clearance was higher among the exposed subjects than among the referents. A dose-response relation was observed between cumulative toluene exposure and both IgE and NAG excretion. No interaction was observed between hypertension and exposure, but the relationship with NAG did not persist when subjects with hypertension were excluded. Past or present exposure did not alter the 2-year trend of any marker studied. CONCLUSIONS: According to the results of this study, toluene at 50 ppm is not related to detectable renal dysfunction. The increased IgE levels associated with present and past exposure require further investigation.

Adult↗
PubMed1997

Accounting for pregnancy dependence in epidemiologic studies of reproductive outcomes.

The aim of this paper is to evaluate the contribution of hierarchical mixed models to the analysis of epidemiologic studies of environmental exposure and reproductive outcomes. We have re-analyzed, with a logistic-normal mixed model, four studies investigating the relation between the frequency of spontaneous abortions and paternal or maternal environmental exposures. The data include multiple pregnancies for some women. The fitted models allow for between-woman variation of the propensity for spontaneous abortion, by including a random intercept in the logistic model to adjust for within-woman correlations on pregnancy outcomes. We have discussed and implemented two estimation methods, maximum likelihood and Bayesian inference. We found similar values in the various epidemiologic studies of the between-woman variance of the intrinsic risk of spontaneous abortion. The size of this variance corresponds to a substantial variability in risk between women. Indeed, the risk of spontaneous abortion calculated for "nonexposed" pregnancies, that is, with mother's age, birth order, tobacco consumption, and maternal environmental exposure equal to the referent class, can vary, according to this model, from 2% to 17%.

Abortion, Spontaneous↗
PubMed1996

Hairy cell leukaemia and occupational exposure to benzene.

OBJECTIVES: The role of occupational exposures in hairy cell leukaemia (HCL) was investigated through a multicentre, hospital based, case-control study. This paper analyses the role of exposure to benzene in HCL. METHODS: A population of 226 male cases of HCL and 425 matched controls were included in the study. Benzene exposure was evaluated by expert review of the detailed data on occupational exposures generated by case-control interviews. RESULTS: No association was found between HCL and employment in a job exposed to benzene (odds ratio (OR) 0.9 (95% confidence interval (95% CI) 0.6-1.3)). The sample included 125 subjects, 34 cases (15%), and 91 controls (21%) who had been exposed to benzene, as individually assessed by the experts, for at least one hour a month during one of their jobs. Benzene exposure was not associated with a risk of HCL (OR 0.8 (0.5-1.2)). No trend towards an increase in OR was detected for increasing exposures, the percentage of work time involving exposure to > 1 ppm, or the duration of exposure. No findings suggested a particular risk period, when the OR associated with the time since first or last exposure, or since the end of exposure, were examined. CONCLUSIONS: In conclusion, with the low exposures prevalent in the sample, the study did not show any association between benzene exposure and HCL.

Benzene↗
PubMed1996

Farming, pesticide use and hairy-cell leukemia.

OBJECTIVES: This paper analyzes the role of farming and pesticide exposures in the occurrence of hairy-cell leukemia (HCL). METHODS: The study included 226 men with HCL and 425 matched hospital referents. Pesticide exposure was assessed by expert review of detailed interview data on occupational histories and agricultural activities and exposures. RESULTS: Altogether, 77 cases and 116 referents had farmed for at least six months, giving an odds ratio (OR) of 1.5 [95% confidence interval (95% CI) 1.0-2.2]. Forage growing was reported by 20.8% of the cases and 11.1% of the referents and was associated with HCL (OR 2.8, 95% CI 1.6-4.9), even among farmers who had never handled pesticides (OR 3.4, 95% CI 1.0-11.0). A significant association was found between HCL and pesticide use, the overall odds ratios for insecticide, fungicide, and herbicide use ranging from 1.5 to 2.4. Organophosphorus insecticides were the only agrochemicals with a positive association with HCL after other pesticide exposures, smoking, and forage growing were accounted for. A clear-cut negative interaction was found between smoking and exposure to organophosphorus insecticides. A multivariate analysis yielded odds ratio estimates of 2.8 (95% CI 1.4-5.6) for exposure to forage and 7.5 (95% CI 0.9-61.5) for nonsmokers exposed to organophosphorus insecticides. CONCLUSIONS: The present study argues for a role of organophosphorus insecticides in HCL among nonsmoking farmers and shows an unexpected association with forage growing. No evidence of an association with phenoxyacetic acids, triazines, or organochlorine insecticides was found.

Adult↗
PubMed1996

[Glomerular nephropathies and exposure to organic solvents--a case-control study].

Several studies have suggested that exposure to organic solvents is associated with glomerular nephropathies (GN), but this relationship remains controversial. A case-control study of 298 biopsy-proven cases and 298 hospital controls, matched for year of birth, sex, origin, and place of residence, was conducted between 1989 and 1991 in five hospitals in the Paris area : 82 cases of membranous glomerulopathy were included ; 100, nephrotic syndrome with either minimal change nephropathy or focal and segmental hyalinosis (MCN/FSH); and 116, IgA nephropathy (IgA N). Subjects were interviewed about their lifelong occupational and non-occupational activities. Type, level, and duration of solvent exposure were assessed blind with respect to case-control status by two industrial hygienists. HLA phenotypes were determined. Among males, a clear association, which was not explained by social class, was observed between chronic renal failure and high exposure to solvents for both MCN/FSH (OR = 7.7, 95% CI 1.4-41.6) and IgA N (OR = 3.5, 95% CI 1.0-11.8). The odds ratios increased with duration of exposure. No relationship was observed between such exposure and GN cases with normal renal function. No evidence was found that the HLA phenotype plays a role in the solvent exposure-disease association. These results support the hypothesis of a causal relationship between high solvent exposure, which concerned 15% of the males in this study, and the development of GN with chronic renal failure.

Adult↗
PubMed1995

CYP2D6 genotype and lung cancer risk according to histologic type and tobacco exposure.

Polymorphism for CYP2D6 was determined genetically as part of a hospital-based case-control study. The cases were males with a histologically confirmed lung cancer diagnosis, < 75 years old, and no previous cancer diagnosis. Male controls were matched for age, hospital and residence area. This study includes 301 cases and 310 controls. A DNA bank was established for 547 patients (89.5%), and genotypes for CYP2D6 were differentiated by the Heim and Meyer method for the DNA samples of 249 cases and 271 controls. Among the cases, the frequencies of homozygous for the wild-type (EM), heterozygous (HEM) and homozygous for the mutant alleles (PM) were 62%, 32% and 7%; among the controls: 57%, 37% and 6%. Using EM as the reference, and adjusting for age, hospital and residence, we estimated the odds ratios for the HEM group and the PM group at 0.8 (95% CI [0.5-1.2]) and 1.1 (95% CI [0.5-2.4]) respectively. The PM frequency among the cases of adenocarcinoma was twice as high as among the controls (OR = 1.8, 95% CI [0.7-4.9]). This result was not observed among squamous and small cell carcinoma (OR = 0.7, 95% CI [0.3-1.8]). Twelve different case-control studies on CYP2D6 and lung cancer have so far been performed; the ORs they estimate range from 0.1 to 2.0, with a median value of approximately 0.6. This result lends some support to the hypothesis that belonging to the PM group is associated with a slight protective effect against lung cancer, but does not take into account the possibility that results may vary according to histologic type. In this context, the suggestion of a positive relationship between CYP2D6 and adenocarcinoma seems to us to merit investigation.

Adult↗
PubMed1995

Organic solvent exposure may increase the risk of glomerular nephropathies with chronic renal failure.

BACKGROUND: Several studies have suggested that exposure to organic solvents is associated with glomerular nephropathies (GN), but this relationship remains controversial. METHODS: A case-control study of 298 biopsy-proven cases and 298 hospital controls, matched for year of birth, sex, origin, and place of residence, was conducted between 1989 and 1991 in five hospitals in the Paris area: 82 cases of membranous glomerulopathy were included; 100, nephrotic syndrome with either minimal change nephropathy or focal and segmental hyalinosis (MCN/FSH); and 116, IgA nephropathy (IgA N). Subjects were interviewed about their lifelong occupational and non-occupational activities. A 'blind' assessment of type, level, and duration of solvent exposure was carried out by two industrial hygienists. Human leucocyte antigen (HLA) phenotypes were determined. RESULTS: Among males, a clear association, which was not explained by social class, was observed between chronic renal failure and high exposure to solvents for both MCN/FSH (OR = 7.7, 95% CI: 1.4-41.6) and IgA N (OR = 3.5, 95% CI: 1.0-11.8). The odds ratios increased with duration of exposure. No relationship was observed between such exposure and GN cases with normal renal function. No evidence was found that the HLA phenotype plays a role in the association between solvent exposure and the disease. CONCLUSIONS: These results support the hypothesis of a causal relationship between high solvent exposure, which concerned 15% of the males in this study, and the development of GN with chronic renal failure.

Adult↗
PubMed1995

Hairy cell leukaemia, occupation, and smoking.

The roles of farm practices, occupational exposures to organic solvents, and ionizing radiation in the risk of hairy cell leukaemia (HCL) were examined in a French hospital-based multicentre case-control study including 291 cases (229 men and 62 women) and 541 controls (425 men and 116 women). No positive association was observed with occupations involving exposure to organic solvents or with self-declared exposures to solvents, but a significant association with self-reported exposure to petrol or diesel was found for men (OR = 1.5 CI95% [1.0-2.1]). No association with ionizing radiation was detected. Agriculture employment gave an odds ratio of 1.7 (CI95% [1.1-2.4]) for men and 2.7 (CI95% [1.1-6.7]) for women. Among men, the association seems to affect farmers rather than agricultural workers. Self-declared exposure to pesticides or bovine cattle breeding was related to HCL risk in both genders. Finally, a significant negative association with smoking was observed in men, with an inverse exposure-risk relationship odds ratios of 0.6, 0.5 and 0.2, respectively, for cumulative consumptions of < 10, 10-23 and > or = 24 pack-years), contrasting with an odds ratios clearly > 1 in women.

Agricultural Workers' Diseases↗
PubMed1995

Performance of odds ratios obtained with a job-exposure matrix and individual exposure assessment with special reference to misclassification errors.

OBJECTIVES: Individual assessment of exposure by experts and the use of a job-exposure matrix are the two main methods of evaluating past occupational exposures in community-based case-referent studies. The objective of this study was to compare the performance of the estimations of the odds ratio in the two methods. This paper focuses on job-exposure matrices whose entries consist of proportions of persons exposed. METHODS: Simulations were used to compare the variances of the estimations of the odds ratios obtained with the two methods and to study the consequences with respect to bias and the precision of the odds ratios estimated for misclassifications of exposure produced by either the experts or the matrix. RESULTS: When there was no misclassification, the results showed that the precision obtained with the job-exposure matrix was about three times less than that achieved by experts in a large range of practical situations. However, when potential errors of exposure assessment were taken into account, the simulations suggested that the test of the hypothesis OR = 1 against the alternative OR not equal to 1 when exposure was assessed with an unbiased job-exposure matrix had a statistical power close to that obtained when exposure was assessed by an expert with high sensibility and specificity. CONCLUSIONS: The evaluation of exposure with an unbiased job-exposure matrix in studies of the association between exposure and disease had a statistical power close to that expected in practice with a good expert in the large range of practical situations which were investigated.

Bias↗
PubMed1995

[Epidemiologic research on the environment and health: some methodologic aspects].

Research in environmental epidemiology deals with physical, chemical and biological agents whose presence--or relative absence--within the different media coming into contract with human beings (air, water, soil, food, etc...) may be harmful to human health. Some "major" environmental risk factors are well known. In a number of situations, however, environment-disease associations are "weak". This does not rule out the possibility that the exposures involved have a significant impact on human health, considering their prevalence which is frequently high. However, this complicates their study owing to the potential importance of biases as well as that of sampling fluctuations. Although increasing study size is of crucial importance, it is not sufficient to establish a clearcut distinction between "weak" associations and "diluted" ones. To improve our knowledge of health risks which are associated with environmental exposures, the basic methodological principles of epidemiological research--to define and adequately measure exposures, health outcomes, confounders and effect modifiers--may be very valuable to approach the study of "weak" associations: 1) identifying and quantifying the presence of the agents of interest in the environment, studying the distribution of environmental exposures among individuals and its determinants, taking into account the whole history of personal exposures and integrating adequately the short term time variability of exposures, giving special attention to the type and intensity of exposures may help in the definition and measurement of exposures; 2) carefully analyzing the interactions which may exist between the physical, chemical and biological agents of interest and the human body may greatly help in the elaboration, measurement and validation of relevant health outcomes (exposures to the target organs, early lesions and health impairments); 3) this same approach may also greatly contribute to the identification of constitutional or acquired individual characteristics which may interact with environmental agents in the development of diseases. While there is no guarantee that such approaches will successfully discriminate between "weak" and "diluted" associations, it is likely that inconclusive epidemiological evidence will be very difficult to avoid if such approaches are neglected by environmental epidemiologists.

Bias↗
PubMed1995

[Early markers of nephrotoxicity: variation factors and reproducibility].

Epidemiological validity of early markers of nephrotoxicity currently used in occupational epidemiology has been poorly investigated. The aim of this study was to identify variation factors of these markers, to quantify their intra- and inter-individual variability and to evaluate the consequences of these results on study size and power. A cross-sectional survey was carried out in 1991 in a rotogravure plant including 168 male subjects (92 exposed to toluene and 76 controls). Blood and urine samples were taken twice: at study onset and one to five months later for 40% of the subjects. Creatinine and beta-2-microglobulin (beta 2M) were measured in both blood and urine; microalbumin (microALB), N-acetyl-beta-D-glucosaminidase (NAG), and alanine-aminopeptidase (AAP), in urine. Sources of physiological variation were reduced by standardization of collection and assay methods. Subjects completed a questionnaire to record information about their personal characteristics, alcohol, tobacco and drug consumption and their health. Statistical analysis of all subjects was adjusted for exposure status. Several factors were significantly related to the markers: age with beta 2M, NAG and AAP; smoking, alcohol drinking, and blood pressure with both microALB and NAG; urinary pH with beta 2M. These factors explained from 13 to 21% of the total variance of these markers. Short-term reproducibility, i.e. the correlation between the two measurements, was high for microALB (r = 0.75), moderate for NAG (r = 0.51), and low for beta 2M (r = 0.33) and AAP (r = 0.17). These results showed that confusion bias in the evaluation of exposure-marker association can be reduced by adjusting for several factors and that accuracy and study power can be improved by repeating measurements, especially for beta 2M and AAP.

Acetylglucosaminidase↗
PubMed1994

Occupational exposure to polycyclic aromatic hydrocarbons and the risk of bladder cancer: a French case-control study.

BACKGROUND: The risk of bladder cancer has been shown to be increased in occupations which are likely to involve exposure to polycyclic aromatic hydrocarbons (PAH), but up to now, most studies have considered this exposure in terms of job title. METHODS: A hospital-based case-control study of 658 male cases of bladder cancer and 658 male controls was carried out in five areas of France from 1984 to 1987. For each subject, occupational exposure to PAH was assessed from questionnaires by an expert according to a semi-quantitative index of exposure. RESULTS: The overall odds ratio for PAH exposure, adjusted for smoking, coffee drinking and occupational exposure to aromatic amines was estimated at 1.3 (95% CI: 1.0-1.7, P < 0.05). A slight but clear dose-response relationship was observed, and the trend remained significant after adjustment for cumulative smoking, with odds ratios of 1.2 (95% CI: 0.9-1.7), 1.4 (95% CI: 0.9-2.2) and 1.8 (95% CI: 0.8-3.9) for low, medium and high average exposures respectively compared to subjects unexposed to PAH (P for trend < 0.05). Moreover, the association between bladder cancer and PAH exposure was also investigated in a category of smokers homogeneous with respect to their tobacco consumption. In this heavy-smoker group, a stronger association with PAH was detected. CONCLUSIONS: These results support the hypothesis of a causal relationship between occupational exposure to PAH and bladder cancer risk.

Adult↗
PubMed1994

Occupational paternal exposure to benzene and risk of spontaneous abortion.

OBJECTIVE: The purpose of this study was to evaluate the risk of spontaneous abortion among the wives of male workers occupationally exposed to benzene. METHODS: The wives of 823 men working in two chemical plants at the time of the study were asked to complete a questionnaire describing their pregnancies. The analysis of the 1739 pregnancies that ended in a spontaneous abortion or a birth is presented. The firms' payroll records provided all workers' employment history, including dates. Benzene exposure, graded at two levels (< 5, > or = 5 ppm), was determined for every job, so that benzene exposure for each worker's entire professional life (at these companies) could be assessed. This information was linked to the dates of the pregnancies reported in the questionnaires to enable the exposure status of each pregnancy to be defined (1270 non-exposed and 274 exposed). The frequency of spontaneous abortion, defined as the number of spontaneous abortions divided by the total of spontaneous abortions and births was evaluated. RESULTS: When adjusted for tobacco consumption, mother's age and pregnancy order, the odds ratio of the association between paternal exposure to approximately 5 ppm of benzene and the risk of spontaneous abortion was close to and statistically not different from unity (OR = 1.1; 95% CI (0.7-1.8). CONCLUSION: In this study paternal exposure to benzene did not increase the risk of spontaneous abortion.

Abortion, Spontaneous↗
PubMed1994

[Job exposure matrices].

During the last years, the use of Job Exposure Matrices (JEMs) for the evaluation of past occupational exposures has grown. This approach is described in this paper. The definition of a JEM is provided. The development process of a JEM is discussed. It includes the choice of the job classification system which influences the degree to which the matrix can be used in other studies, the precise definition of exposures and the choice of entries which should provide more information than the oversimplified exposed/non exposed dichotomy. When comparing JEMs and experts' evaluation of exposure, all aspects of both methods have to be looked at and a balance struck between the advantages and shortcomings of each of them. The problem should not be reduced to a single choice between the precision provided by experts, and the cost savings and standardization offered by JEMs. Statistical analysis with a JEM must be adapted to the job classified information it provided. When an appropriate method is used, the loss of power with a JEM compared to experts' evaluation is rather small or even null. Finally, it is important to avoid a systematic opposition between JEMs and expert assessments, as one positive result of their comparison may be the improvement of both methods of exposure evaluation.

Biometry↗