Occupational exposure to organic solvents and the risk of developing testicular germ cell tumors (TESTIS study): Effect of combined exposure assessment on risk estimation.

OBJECTIVES: Etiological factors of testicular germ cell tumors (TGCT) remain largely unknown, but a causal role of occupational exposures to solvents has been suggested. Previous studies analyzing these exposures reported discordant results, potentially related to exposure assessment methods. The aim of this study was to investigate the role of occupational exposure to solvents on the risk of developing TGCT among young men. METHODS: This study examined occupational exposures to solvents and TGCT risk based on the lifetime work histories of 454 cases and 670 controls, aged 18-45 years, of the French national TESTIS case-control study. Solvent exposure was estimated using: (i) exposure assignment by job-exposure matrix (JEM) and (ii) JEM combined with self-reported exposure data from specific questionnaires (SQ) and expert assessment (EA). Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression models. RESULTS: Both approaches (JEM and JEM+SQ+EA) showed a consistent association between TGCT and trichloroethylene exposure (exposed versus not exposed; JEM=OR 1.80 [95% confidence interval (CI) 1.12-2.90] and JEM+SQ+EA= OR 2.59 (95% CI 1.42-4.72). Both approaches also observed positive associations with ketone esters and fuels & petroleum-based solvents. CONCLUSION: The results suggest that some organic solvents might be involved in the pathogenesis of TGCT among occupationally exposed men. The combined use of JEM+SQ+EA seemed to limit misclassification by considering individual exposure variability and is, therefore, an appealing approach to assess occupational exposures in epidemiological studies.

Parental occupations at birth and risk of adult testicular germ cell tumors in offspring: a French nationwide case-control study.

Background: Testicular germ cell tumors (TGCT) are the most frequent cancer in young men in developed countries. Parental occupational exposures during early-life periods are suspected to increase TGCT risk. The objective was to estimate the association between parental occupations at birth and adult TGCT. Methods: A case-control study was conducted, including 454 TGCT cases aged 18-45 from 20 French university hospitals, matched to 670 controls based on region and year of birth. Data collected from participants included parental jobs at birth coded according to the International Standard Classification of Occupation-1968 and the French nomenclature of activities-1999. Odds ratios (OR) for TGCT and 95% confidence intervals (CI) were estimated using conditional logistic regression, adjusting for TGCT risk factors. Results: Paternal jobs at birth as service workers (OR = 1.98, CI 1.18-3.30), protective service workers (OR = 2.40, CI 1.20-4.81), transport equipment operators (OR = 1.96, CI 1.14-3.37), specialized farmers (OR = 2.66, CI 1.03-6.90), and maternal jobs as secondary education teachers (OR = 2.27, CI 1.09-4.76) or in secondary education (OR = 2.35, CI 1.13-4.88) were significantly associated with adult TGCT. The risk of seminoma was increased for the above-mentioned paternal jobs and that of non-seminomas for public administration and defence; compulsory social security (OR = 1.99, CI 1.09-3.65); general, economic, and social administration (OR = 3.21, CI 1.23-8.39) for fathers; and secondary education teacher (OR = 4.67, CI 1.87-11.67) and secondary education (OR = 3.50, CI 1.36-9.01) for mothers. Conclusion: Some paternal jobs, such as service workers, transport equipment operators, or specialized farmers, and maternal jobs in secondary education seem to be associated with an increased risk of TGCT with specific features depending on the histological type. These data allow hypotheses to be put forward for further studies as to the involvement of occupational exposures in the risk of developing TGCT, such as exposure to pesticides, solvents, or heavy metals.

Urinary biomarkers of exposure to glycol ethers and chlorinated solvents during pregnancy: determinants of exposure and comparison with indirect methods of exposure assessment.

OBJECTIVES: To describe urine levels of metabolites of glycol ethers and chlorinated solvents in a sample of pregnant women from the general population, to study their occupational and non-occupational determinants and to compare them with the results of indirect assessment methods of solvent exposure. METHODS: A sample of 451 pregnant women was randomly selected from a general population cohort. At inclusion, the women in this sample completed a self-administered questionnaire about their social and medical characteristics, occupation and exposure to different products at work and in non-occupational activities. Occupational exposure to solvents was assessed from the woman's self-report and from a job-exposure matrix. Eight alkoxycarboxylic acids and trichloroacetic acid and trichloroethanol were measured with chromatography in urine samples collected at inclusion. Associations between metabolite levels and job titles, exposure to products used at work, and solvent exposure were studied. RESULTS: The different glycol ether metabolites were detected in 5.3%-96.4% of the urine samples, trichloroacetic acid in 6.4% and trichloroethanol in 5.5%. Nurses had butoxyacetic acid and phenoxyacetic acid in their urine most often, whereas methoxyethoxyacetic acid was the most frequent among nursing aides. Among cleaners, ethoxyacetic acid and ethoxyethoxyacetic acid were the most frequent. The occupation of hairdresser was associated with urinary excretion of ethoxyacetic acid, ethoxyethoxyacetic acid, butoxyacetic acid and phenoxyacetic acid. Among the women classified as exposed to solvents, the agents identified most often were ethoxyacetic acid, ethoxy-ethoxyacetic acid, butoxyacetic acid, phenoxyacetic acid, trichloroacetic acid and trichloroethanol. Ethoxyethoxyacetic acid was the only metabolite associated with non-occupational exposure. CONCLUSIONS: Metabolites of glycol ethers and chlorinated solvents were present at low levels in the urine of pregnant women. Most metabolites were associated with occupational exposure.