A population-based case-control study on social factors and risk of testicular germ cell tumours.

OBJECTIVES: Incidence rates for testicular cancer have risen over the last few decades. Findings of an association between the risk of testicular cancer and social factors are controversial. The association of testicular cancer and different indicators of social factors were examined in this study. DESIGN: Case-control study. SETTING: Population-based multicentre study in four German regions (city states Bremen and Hamburg, the Saarland region and the city of Essen). PARTICIPANTS: The study included 797 control participants and 266 participants newly diagnosed with testicular cancer of which 167 cases were classified as seminoma and 99 as non-seminoma. The age of study participants ranged from 15 to 69 years. METHODS: Social position was classified by educational attainment level, posteducational training, occupational sectors according to Erikson-Goldthorpe-Portocarrero (EGP) and the socioeconomic status (SES) on the basis of the International SocioEconomic Index of occupational status (ISEI). ORs and corresponding 95% CIs (95% CIs) were calculated for the whole study sample and for seminoma and non-seminoma separately. RESULTS: Testicular cancer risk was modestly increased among participants with an apprenticeship (OR=1.7 (95% CI 1.0 to 2.8)) or a university degree (OR=1.6 (95% CI 0.9 to 2.8)) relative to those whose education was limited to school. Analysis of occupational sectors revealed an excess risk for farmers and farm-related occupations. No clear trend was observed for the analyses according to the ISEI-scale. CONCLUSIONS: Social factors based on occupational measures were not a risk factor for testicular cancer in this study. The elevated risk in farmers and farm-related occupations warrants further research including analysis of occupational exposures.

Exposure to metal-working fluids in the automobile industry and the risk of male germ cell tumours.

INTRODUCTION: In a previous analysis of a case-control study of testicular cancer nested in a cohort of automobile workers, we observed an increased risk for testicular cancer among workers who had ever been involved in occupational metal-cutting tasks. We investigated whether this risk increase was due to exposure to metal-working fluids (MWF). METHODS: Occupational exposure to MWF was assessed in detail using a job-specific questionnaire for metal-cutting work. We calculated ORs and associated 95% CIs individually matched for age (±2 years) and adjusted for a history of cryptorchidism by conditional logistic regression. RESULTS: The prevalence of exposure to MWF was 39.8% among cases and 40.1% among controls. For total germ cell tumours and seminomas we did not observe risk increases for metal-cutting tasks or occupational exposure to MWF (OR 0.95; 95% CI 0.69 to 1.32 and OR 0.88; 95% CI 0.58 to 1.35, respectively). However, dermal exposure to oil-based MWF was associated with an increased risk for non-seminomatous testicular cancer. Dermal exposure to oil-based MWF for more than 5000 h showed particularly high risk estimates (OR 4.72; 95% CI 1.48 to 15.09). DISCUSSION: Long-term dermal exposure to oil-based MWF was a risk factor for the development of non-seminomatous testicular germ cell cancer. Possible measures to reduce exposure include the introduction of engineering control measures such as venting or enclosing of machines, and enforcing the use of personal protective equipment during metal cutting.

Development and evaluation of a tool for retrospective exposure assessment of selected endocrine disrupting chemicals and EMF in the car manufacturing industry.

OBJECTIVES: A system for retrospective occupational exposure assessment combining the efficiency of a job exposure matrix (JEM) and the precision of a subsequent individual expert exposure assessment (IEEA) was developed. All steps of the exposure assessment were performed by an interdisciplinary expert panel in the context of a case-control study on male germ cell cancer nested in the car manufacturing industries. METHODS: An industry-specific JEM was developed and automatic exposure estimation was performed based on this JEM. A subsample of exposure ratings was done by IEEA to identify determinants of disagreement between the JEM and the individual review. Possible determinants were analyzed by calculating odds ratios (ORs) of disagreement between ratings with regard to different dimensions (e.g. high versus low intensity of exposure). Disagreement in ≥20% of the sampled exposure ratings with a statistically significant OR was chosen as a threshold for inclusion of the exposure ratings into a final IEEA. RESULTS: The most important determinants of disagreement between JEM and individual review were working outside of the production line (disagreement 80%), low probability of exposure (disagreement 25%), and exposure depending on specific activities like usage of specific lacquers (disagreement 32%) for jobs within the production line. These determinants were the selection criteria of exposure ratings for the subsequent final IEEA. CONCLUSIONS: Combining a JEM and a subsequent final IEEA for a selected subset of exposure ratings is a feasible and labor-saving approach for exposure assessment in large occupational epidemiological studies.

Case-control study of male germ cell tumors nested in a cohort of car-manufacturing workers: Findings from the occupational history.

BACKGROUND: To examine whether the previously observed excess risk of male germ cell cancer in a cohort of car-manufacturing workers can be attributed to occupational activities inside and/or outside the car industry. METHODS: A nested case-control study among workers in six plants included 205 cases of germ cell cancer and 1,105 controls, individually matched by year of birth (±2 years). Job periods of the individual occupational histories were coded based on the International Standard Classification of Occupations (ISCO) and the industrial classification of economic activities (NACE). Odds ratios (ORs) and corresponding 95%-confidence intervals (CI) for ever-never and cumulative employment were calculated by conditional multivariate logistic regression adjusted for cryptorchidism. RESULTS: Significantly increased risks were observed for machinery fitters and assemblers (A) (OR = 1.8, 95% CI 1.25-2.53) and "workers not elsewhere classified" (OR = 2.10, 95% CI 1.27-3.54), but no trend was observed for employment duration in either occupational group. Stratification of job group A by metal-cutting and non-cutting jobs yielded ORs of 1.87 (95% CI 1.31-2.67) and of 1.24 (95% CI 0.68-2.28), respectively. Among "plumbers, welders, sheet & structural metal workers" (adjusted OR 1.4, 95% CI 0.99-1.95) only "structural metal preparers and erectors" showed a substantially increased risk (OR = 2.30; 95% CI 1.27-4.27). CONCLUSIONS: Our results do not fully explain the increased incidence of germ cell cancer in the cohort, but support previous findings showing increased risks among metal workers. These risks were most strongly pronounced in metal-cutting activities.