Papers

Incidence of cancer among Nordic airline pilots over five decades: occupational cohort study

Eero Pukkala, epidemiologist, ^a Rafael Aspholm, airline pilot, ^b Anssi Auvinen, professor, ^c Harald Eliasch, medical consultant, ^d Maryanne Gundestrup, senior registrar, ^e Tor Haldorsen, epidemiologist, ^f Niklas Hammar, epidemiologist, ^g Jón Hrafnkelsson, medical doctor, ⁱ Pentti Kyyrönen, statistician, ^a Anette Linnersjö, statistician, ^h Vilhjálmur Rafnsson, professor, ^j Hans Storm, medical doctor, ^k Ulf Tveten, senior scientist. ^l

^a Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Liisankatu 21 B, FIN-00170 Helsinki, Finland, ^b Finnish Airline Pilots' Association, FIN-01530 Vantaa, Finland, ^c STUK, Radiation and Nuclear Safety Authority, FIN-00881 Helsinki, Finland, ^d Swedish SAS, S-19587 Stockholm, Sweden, ^e National Clinic of Aviation Medicine, Heart Centre, University Hospital, DK-2220 Copenhagen N, Denmark, ^f Kreftregisteret, Institute of Population-based Cancer Research, N-0310 Oslo, Norway, ^g Institute of Environmental Medicine, Karolinska Institute, S-17177 Stockholm, Sweden, ^h Department of Epidemiology, Stockholm Centre of Public Health, S-17176 Stockholm, Sweden, ⁱ Department of Oncology, Landspitalinn, ICE-105 Reykjavik, Iceland, ^j Department of Preventive Medicine, University of Iceland, ICE-105 Reykjavik, Iceland, ^k Cancer Prevention and Documentation, Danish Cancer Society, DK-2100 Copenhagen Ø, Denmark, ^l Institute for Energy Technology, N-2007 Kjeller, Norway

Correspondence to: E Pukkala eero.pukkala{at}cancer.fi

Objective: To assess the incidence of cancer among male airline pilots in the Nordic countries, with special reference to risk related to cosmic radiation.
Design: Retrospective cohort study, with follow up of cancer incidence through the national cancer registries.
Setting: Denmark, Finland, Iceland, Norway, and Sweden.
Participants: 10 032 male airline pilots, with an average follow up of 17 years.
Main outcome measures: Standardised incidence ratios, with expected numbers based on national cancer incidence rates; dose-response analysis using Poisson regression.
Results: 466 cases of cancer were diagnosed compared with 456 expected. The only significantly increased standardised incidence ratios were for skin cancer: melanoma 2.3 (95% confidence interval 1.7 to 3.0), non-melanoma 2.1 (1.7 to 2.8), basal cell carcinoma 2.5 (1.9 to 3.2). The relative risk of skin cancers increased with the estimated radiation dose. The relative risk of prostate cancer increased with increasing number of flight hours in long distance aircraft.
Conclusions: This study does not indicate a marked increase in cancer risk attributable to cosmic radiation, although some influence of cosmic radiation on skin cancer cannot be entirely excluded. The suggestion of an association between number of long distance flights (possibly related to circadian hormonal disturbances) and prostate cancer needs to be confirmed.

What is already known on this topic Airline pilots are occupationally exposed to cosmic radiation and other potentially carcinogenic elements In the studies published so far, dose-response patterns have not been characterised What this study adds No marked risk of cancer attributable to cosmic radiation is observed in airline pilots A threefold excess of skin cancers is seen among pilots with longer careers, but the influence of recreational exposure to ultraviolet light cannot be quantified A slight increase in risk of prostate cancer with increasing number of long haul flights suggests a need for more studies on the effects of circadian hormonal disturbances