Occupational risk factors for lung cancer in the French electricity and gas industry: a case-control survey nested in a cohort of active employees.

The main aim of this study was the analysis of occupational lung cancer risk factors in the French national electricity and gas company (Electricité de France-Gaz de France (EDF-GDF)). A case-control survey nested in a cohort of male employees was undertaken. The study population consisted of all male staff who were active at EDF-GDF between January 1, 1978, and December 31, 1989. During this period, 310 cases of lung cancer were identified in the cancer register set up by the medical department of the company. For each case, four age-matched controls who were free of cancer at the time of occurrence of the case's lung cancer were randomly selected. Occupational exposures to 21 chemical agents were assessed for each subject using a job exposure matrix. The associations between lung cancer and the different agents were estimated using conditional logistic regression analysis. After adjustment for various occupational confounding factors, the analysis showed increased lung cancer risks linked to exposure to crystalline silica (highest exposure class: odds ratio = 2.27; 95% confidence interval: 1.10, 4.68) and creosotes (highest exposure level: odds ratio = 2.14; 95% confidence interval: 1.06, 4.31), with significant dose-response relationships for both exposures.