SUPERMODEL Elle MacPherson reportedly puts her baby in a lead-lined cot during flights. And she is not the only frequent flyer who worries about the higher levels of cosmic radiation. But the good news, according to the biggest study to date, is that the extra doses of cosmic rays do not increase your chances of dying from cancer.
At the cruising altitude of 10,000 metres, people are exposed to up to 150 times as much cosmic radiation as at sea level, and levels are even higher near the poles. Passengers are exposed for so little time it鈥檚 not considered dangerous. But some studies have suggested that aircrews are twice as likely to get breast cancer, and 15 times as likely to get skin cancer. But these studies only looked at small groups. Now a much larger study of 44,000 airline crew from eight European countries has found that cancer deaths among them are no higher than in the rest of the population (American Journal of Epidemiology, vol 158, p 35).
The team did find a twofold increase in skin cancer deaths in men, but suspect this is due to other factors. 鈥淧ilots go on vacation more often than other people and they get free flights. There鈥檚 anecdotal evidence that they鈥檙e in the sun more often than other people,鈥� says team member Maria Blettner of the University of Bielefeld, Germany. Indeed, a separate study of 28,000 pilots, to be published by the same team in the International Journal of Cancer, found there were one third fewer deaths from cancer in pilots.
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According to conventional models, people who spend 750 hours in the air annually for 30 years should be 10 per cent more likely to get cancer. The study did not reveal any such increase. But most of the crew are still young and may yet develop cancer. 鈥淚t鈥檚 not yet the end of the day,鈥� says Blettner. She says cautionary policies, such as taking pregnant crew off duty, are still reasonable.