Cosmic radiation and lifestyle factors, such as more frequent sunbathing, could also be involved, but scientists at the University of Reykjavik said pilots who flew over five or more time zones had 25 times as many cases of malignant melanoma as the general population.
Malignant melanoma is the most serious form of skin cancer.
Dr Vilhjalmur Rafnsson told Reuters. Circadian rhythms regulate sleep patterns and the hormone melatonin, a chemical naturally released by the brain to induce sleep. It has recently been tried in the treatment of malignant melanoma,'' Rafnsson said in a telephone interview. He stressed that the role of melatonin in the high incidence of the disease among the long-haul pilots was just speculation and more research still needs to be done. The next thing to do is to study larger groups of pilots and whether they are sunbathing all the time,'' he said.