Why Do Airline Pilots and Flight Crews Have an Increased Incidence of Melanoma?

Because of the unique occupational risk factors of commercial pilots, cabin crew, and flight attendants, numerous studies have investigated their risks for variousdiseases. Ingeneral,mortality from cancer, as well as cardiovascular, respiratory, and cerebrovascular diseases, is significantly lower inpilotsandcabincrewcomparedwith the general population.1 However, despite their overall improved healthoutcomes, pilots and flight crewhavebeen reported tohave an increased incidence and/or mortality frommelanoma.2,3 The report published in JAMADermatology in January by Sanlorenzoetal3 assessed the riskofmelanomaamongairlinepilotsand cabin crew in ameta-analysis that included 19previously published studies.Thestudies reflectdata from1943to2008and includemore than 266 000 pilots and cabin crew. These 19 studies were selected because they reported a standardized incidence ratio (SIR) or a standardized mortality ratio (SMR) or had relevant data to allow for calculation of these established measures of disease incidenceanddeath.Pilots andcabin crewwere found tohaveapproximately twice the incidence ofmelanomawhen comparedwith the generalpopulation (SIR,2.21 [95%CI, 1.76-2.77]), andmortality from melanomaamongpilotswassignificantly increased(SMR, 1.83 [95% CI, 1.27-2.63]). Because of the observational and retrospective nature of the 19 studies, it was not possible to control for certain potentially confounding factors suchas aggregate flight time, Fitzpatrick skin type, and lifestyle.3 Pilots and cabin crew are regularly exposed to higher levels of cosmic radiation during flight,4,5 and it is important to consider whether this additional radiation exposure is associated with their increased risk of melanoma. Cosmic (ionizing) radiation is composedof high-energyparticles (neutrons andgamma rays) that are capable of penetrating theplane’s exterior.4 Lower levels of cosmic radiation reach the earth’s surface and lead to annual background radiation exposure of approximately 2mSv per person (to convert JAMADERMATOLOGY