Cancer mortality risk among biology research workers in France: first results of two retrospective cohorts studies.

Objective: To investigate all-cause and cancer mortality of biological research laboratories workers of the French Atomic Energy Commission (CEA) and the National Institute of Health and Medical Research (INSERM).

Methods: Two cohorts, bioCEA (N = 3,509) and bioINSERM (N = 4,966) were followed from 1968 to 1994 and 1980 to 1993, respectively. The mortality of each cohort was compared with that of the French population by computation of the standardized mortality ratio (SMR) with their 90% confidence interval (90% CI). Trend and heterogeneity tests were computed in order to study SMRs variation by job characteristics. In the bioCEA cohort individual dosimetry data being available, a trend test was also computed according to ionizing radiation cumulative dose.

Results: The SMRs were significantly below one in both cohorts for all-cause mortality (bioCEA: SMR = 0.52 [0.46-0.59], bioINSERM: SMR = 0.56 [0.46-0.67]) and for all-cancer mortality (bioCEA: SMR = 0.66 [0.54-0.80], bioINSERM: SMR = 0.55 [0.39-0.75]). There were some specific cancer sites for which the SMR was higher than 1, but not significantly. In the bioCEA cohort a positive trend was observed between ionizing radiation cumulative doses and all-cause as well as all-cancer SMRs.

Conclusion: This study on two French cohorts of biological research workers found a favorable mortality pattern. These findings are consistent with recent publications. The positive trend of cancer mortality according to ionizing radiation exposure among bioCEA cohort needs to be confirmed with more precise assessment of exposures and information on individual risk factors.