Cohort study of occupational cosmic radiation dose and cancer mortality in German aircrew, 1960–2014
Steffen Dreger, Daniel Wollschläger, Thomas Schafft, Gaël P. Hammer, Maria Blettner, Hajo Zeeb
Abstract
OBJECTIVES: To determine cancer mortality compared with the general population and to examine dose-response relationships between cumulative occupational radiation dose and specific cancer outcomes in the German aircrew cohort. METHODS: For a cohort of 26 846 aircrew personnel, standardised mortality ratios (SMR) were calculated. Dose-response analyses were carried out using Poisson regression to assess dose-related cancer risks for the period 1960-2014. Exposure assessment comprises recently available dose register data for all cohort members and newly estimated retrospective cabin crew doses for 1960-2003. RESULTS: SMR for all-cause, specific cancer groups and most individual cancers were reduced in all aircrew groups. The only increases were seen for brain cancer in pilots (n=23, SMR 2.01, 95% CI 1.15 to 3.28) and for malignant melanoma (n=10, SMR 1.88, 95% CI 0.78 to 3.85). Breast cancer mortality among female cabin crew was similar to the general population (n=71, SMR 1.06, 95% CI 0.77 to 1.44). Overall median cumulative effective dose was 34.2 mSv (max: 116 mSv) for 1960-2014. No dose-response associations were seen in any of the models. For brain cancer, relative risks were elevated across dose categories. An indicative negative trend with increasing dose category was seen for large intestine cancer in female cabin crew (n=23). CONCLUSIONS: There was no evidence for significant dose-response patterns for the considered cancer types. Interpretation of results remains difficult as cumulative dose is closely related to age. Future work should focus on investigating radiation jointly with other risk factors that may contribute to risks for specific cancers among aircrew.