Cohort study of occupational cosmic radiation dose and cancer mortality in German aircrew, 1960-2014.
Level 3 - non-randomized controlled study
Retrospective cohort study
PubMed 32075886 · doi:10.1136/oemed-2019-106165
What was done
Standardised mortality ratios (SMRs) and Poisson regression dose-response models were analyzed in a cohort of 26,846 German aircrew personnel followed from 1960 to 2014. Radiation exposure assessments used radiation dose register records and newly estimated retrospective cabin crew doses for 1960–2003 to examine the relationship between cumulative occupational cosmic radiation and cancer mortality.
What was found
The median cumulative effective dose was 34.2 mSv (maximum 116 mSv). SMRs for all-cause mortality, specific cancer groups, and most individual cancers were reduced compared with the general population. Increases were observed for brain cancer in pilots (n=23, SMR 2.01, 95% CI 1.15 to 3.28) and malignant melanoma (n=10, SMR 1.88, 95% CI 0.78 to 3.85). Breast cancer mortality in female cabin crew was comparable to the general population (n=71, SMR 1.06, 95% CI 0.77 to 1.44). No significant dose-response associations were found for any cancer type, though brain cancer relative risks were elevated across all dose categories and an indicative negative trend with increasing dose was observed for large intestine cancer in female cabin crew (n=23).
Why it matters
The findings provide long-term epidemiological evidence that occupational cosmic radiation exposure in aircrew was not associated with dose-dependent increases in cancer mortality over more than five decades of follow-up.
Limits
The abstract notes that cumulative radiation dose is closely correlated with age, complicating the interpretation of dose-response models. The study examined cancer mortality rather than cancer incidence, and non-radiation occupational or lifestyle risk factors were not jointly analyzed.
Cited by
- contradicts Airline pilots have higher rates of cancer, in part due to elevated atmospheric cosmic radiation exposure.