Table 3.

Risk of lung cancer among males associated with occupational exposure to crystalline silica

Study IStudy IIPooled study
Cases versus population controlsCases versus other cancer controlsCa/CoOR0*OR1 (95% CI)Ca/CoOR0*OR1 (95% CI)
Ca/CoOR0*OR1 (95% CI)Ca/CoOR0*OR1 (95% CI)
Unexposed623/42211623/1,05511560/721111,183/1,56511
Any level of exposure234/1111.431.28 (0.93-1.75)234/2941.331.24 (0.99-1.56)178/1781.301.28 (0.95–1.74)412/4001.371.31 (1.08-1.59)
Non-substantial exposure152/821.261.11 (0.78-1.59)152/2121.201.12 (0.86-1.45)139/1401.281.23 (0.88-1.70)291/3021.281.20 (0.97-1.49)
Substantial exposure82/291.921.77 (1.05-2.98)82/821.671.56 (1.09-2.25)39/381.351.53 (0.88-2.67)121/981.641.67 (1.21-2.31)

Abbreviation: Ca/Co, cases/controls.

  • *OR0 is adjusted only for age and, in the pooled study, for initial source study.

  • OR1 is adjusted for several covariates determined a priori, including age; ethnicity; proxy respondent; education level; natural logarithm of median postal code region income; cigarette ever smoking; natural logarithm of cigarette-years; years since quitting smoking; occupational exposure to respirable asbestos, benzo(a)pyrene, chromium VI, and diesel emissions; and, for pooled study, original study (i.e., study I or II). Other covariates such as occupational exposure to respirable arsenic, nickel, and polyaromatic hydrocarbons were examined but not retained because they did not contribute meaningfully to the model.