Aircrew are exposed to elevated levels of cosmic radiation while flying at high altitudes. A recent study from the Harvard T.H. Chan School of Public Health in the United States found that the prevalence of certain cancers in flight attendants was higher than the general population.
While the radiation doses to aircrew are below the national dose limits for occupationally exposed workers, this recent study found a higher prevalence of breast cancer, melanoma and non-melanoma skin cancer compared with the general population. Researchers gathered data on cancer prevalence in 5366 flight attendants and 2729 members of the general public, matched by similar socio-economic status.
While the study was reported in the media, we found that there are a number of considerations that should be taken into account when looking at these results. The study:
- measured cancer at a certain point in time.
The study looked at a comparison of cancer prevalence in flight attendants when compared with cancer prevalence in the general public. As an indicator of the likelihood of developing cancer as a result of working as a flight attendant, cancer prevalence is limited in that it only measures the occurrence of disease at a certain point of time. Although this can serve as an indication of the disease, the evidence supporting the association is weakened by a limited understanding of how the disease rates changed over time. A better indication of the risk factors would have been achieved by measuring the incidence of cancers examined where cases would have been recorded over time.
- estimated radiation dose.
The study did not measure the exposure of the flight attendants to cosmic radiation, and estimated the doses to flight attendants based on how long each person had been working as a flight attendant.
Possible risk factors
The authors identified a number of known and probable carcinogens that flight attendants would be exposed including: ionising radiation, circadian rhythm disruptions from night shift work, irregular schedules and crossing time zones, and poor cabin air quality such as second hand tobacco smoke from before the implementation of smoking bans. The authors also identified (but did not adjust for) confounders such as recreational ultraviolet radiation exposure, including outdoor activities such as hiking or going to the beach.
The results of the study were consistent with similar studies, but given its limitations further studies with improved methods are required.
What is ARPANSA doing about cosmic radiation exposure to aircrew?
We are involved in a study lead by QIMR Berghofer Medical Research Institute investigating the incidence of melanoma in commercial pilots in Australia. The first results of this study will be announced at the Australasian Society of Aerospace Medicine Conference in August 2018.
In 2017 we also published a Guide for Radiation Protection in Existing Exposure Situations (RPS G-2) which gives guidance to aircrew on exposure to cosmic radiation while flying. The advice is that while the radiation doses to aircrew are expected to be low, we recommended airlines assess the exposure situations of their crew, with additional consideration to be made for pregnant aircrew.
Find out more about exposure to cosmic radiation while flying. Our advice for casual flyers and aircrew is that there is no increase in health risk from exposure to naturally occurring cosmic radiation while flying. While this advice remains current and accurate, we are reviewing this factsheet and will include advice to aircrew about ultraviolet radiation exposure.