title: Case-control study of male germ cell tumors nested in a cohort of car-manufacturing workers: Findings from the occupational history.
abstract: 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.
authors.affiliation: Bremen Institute for Prevention Research and Social Medicine, Bremen University, Germany. ingo.langner@bips.uni-bremen.de
authors.forename: Ingo
authors.initials: I
authors.lastname: Langner
authors.forename: Nils
authors.initials: N
authors.lastname: Schmeisser
authors.forename: Birte
authors.initials: B
authors.lastname: Mester
authors.forename: Thomas
authors.initials: T
authors.lastname: Behrens
authors.forename: Andrea
authors.initials: A
authors.lastname: Gottlieb
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Ahrens
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001336:Automobiles; D016022:Case-Control Studies; D002648:Child; D016001:Confidence Intervals; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007221:Industry / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009373:Neoplasms, Germ Cell and Embryonal / Q000453:epidemiology* / Q000209:etiology*; D016273:Occupational Exposure / Q000706:statistics & numerical data*; D009790:Occupations / Q000706:statistics & numerical data*; D016017:Odds Ratio; D012306:Risk; D055815:Young Adult