Do Airline Pilots and Cabin Crew Have Raised Risks of Melanoma and Other Skin Cancers?

Systematic Review and Meta-analysis

K. Miura; C.M. Olsen; S. Rea; J. Marsden; A.C. Green

Disclosures

The British Journal of Dermatology. 2019;181(1):55-64. 

In This Article

Abstract and Introduction

Abstract

Background: Airline pilots and cabin crew are potentially exposed to hazardous ultraviolet and cosmic radiation, which may increase their risk of melanoma and other skin cancers.

Objectives: To establish precise risks of melanoma and keratinocyte cancer (KC) for airline pilots and for cabin crew based on all studies published to date.

Methods: We searched MEDLINE, ISI Science Citation Index, Embase, SCOPUS and CINAHL to June 2018. All studies of melanoma and KC risk and mortality in airline pilots and cabin crew compared with the general population were eligible. Standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) were pooled using random effects models.

Results: From 5866 papers retrieved, we reviewed 44 full-text articles, of which 12 studies with data collected mostly between the 1970s and 1990s were eligible for inclusion. The pooled SIR (pSIR) for melanoma in pilots was 2.03 [95% confidence interval (CI) 1.71–2.40] and in cabin crew it was 2.12 (95% CI 1.71–2.62). For pilots, the pooled SMR for melanoma was 1.99 (95% CI 1.17–3.40) and for cabin crew it was 1.18 (95% CI 0.73–1.89). For KC, the pSIR was 1.86 (95% CI 1.54–2.25) in pilots and 1.97 (95% CI 1.25–2.96) in cabin crew. There was no evidence of study heterogeneity.

Conclusions: The available evidence shows that airline pilots and cabin crew have about twice the risk of melanoma and other skin cancers than the general population, with pilots more likely to die from melanoma. However, most of the evidence was collected several decades ago and their relevance to contemporary levels of risk is uncertain.

Introduction

Airline pilots enjoy substantially better health than the general population: they undergo regular medical examinations and have higher than average socioeconomic status.[1] Despite a lower risk of some cancers,[2,3] airline pilots appear to be at significantly increased risk of developing and dying from melanoma.[4–7] A recent survey reported that melanoma rates among airline pilots were about 50 times higher than those of the general adult population (19 vs. 0.4 per 1000).[6] Specific occupational causes such as increased exposure to cosmic ionizing radiation[8] and ultraviolet (UV) radiation[9] and circadian rhythm disruption[10] are plausible explanations.

Cabin crew are exposed to the same levels of cosmic radiation as pilots and experience the same disruption of circadian rhythm, but they are not likely to be occupationally exposed to UV radiation. A recent meta-analysis of published studies of airline pilots and/or cabin crew reported double the incidence of melanoma in both pilots and cabin crew compared with the general population, with standardized incidence ratios (SIRs) of 2.22, 95% confidence interval (CI) 1.67–2.93 and 2.09, 95% CI 1.67–2.62, respectively.[5] In addition, the standardized mortality ratio (SMR) for melanoma was significantly raised among pilots (SMR 1.83, 95% CI 1.27–2.63) but not among cabin crew (SMR 0.90).[5] However, this analysis included studies of aviation warfare system operators and military pilots as well as nonairline commercial pilots flying short sectors at lower altitudes. Melanoma was not histologically confirmed in all included studies. Data about risk of keratinocyte cancers (KCs) in airline pilots show conflicting results.[2,11,12]

Because of uncertainty about melanoma and KC risk in airline pilots, we undertook a systematic review and meta-analysis of all relevant studies published to date. We also systematically reviewed all published studies and pooled the risk estimates of melanoma in cabin crew as a comparison group. Finally, to supplement these data, we reviewed the published evidence on KC risk in both airline pilots and cabin crew compared with the general population. All studies included were of histologically confirmed melanoma and KCs. As hazardous occupational UV exposure would be restricted to the flight deck and therefore would affect only pilots, we hypothesized that their risk of melanoma and KC compared with the general population would be increased more than the corresponding risk of melanoma and KC seen in cabin crews.

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