Authored By:McNeely et al
This was a retrospective cross-sectional study that investigated the prevalence of specific cancers within flight attendants in the U.S. compared to the general population. Data on cancer prevalence was gathered by surveys returned from 5366 flight attendants and 2729 controls matched by similar socioeconomic status. The study reported a higher prevalence in flight attendants compared to the general population for breast cancer (risk estimate 1.51 with a 95% confidence interval (CI) of 1.02-2.24), melanoma (2.27, 95% CI 1.27-4.06) and non-melanoma cancer (4.09, 95% CI 2.70-6.20). There were no statistically significant associations with the other cancers examined (uterine, cervical, gastrointestinal and thyroid). The authors concluded that there was a higher prevalence of specific cancers within the flight attendant occupation than the general population.
Published In:Environmental Health, June 2018
Commentary by ARPANSA:
Although the authors reported an elevated risk of some cancers in the flight attendant cohort, these associations were based on prevalence of the disease compared to the general population. Prevalence of disease is limited in that it measures the occurrence of a disease at a point in time. Although this can serve as an indicator of the disease, the evidence supporting the associations 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 the cancers examined where cases would have been recorded over the time period.
The study relied on tenure in the occupation as a surrogate for exposure. 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.
Overall, the results of the study were consistent with similar studies but given it’s limitations further studies with improved methods are required. In Australia, ARPANSA is involved in a study lead by QIMR Berhofer Medical Research Institute, investigating the incidence of melanoma in commercial pilots in Australia. The first results from this research are expected later in 2018.