Pilots Have 25 Times
Higher Rate Of Skin Cancer
By Patricia Reaney
LONDON (Reuters) - Airline pilots have up to 25 times the normal rate of skin cancer and it could be due partly to disturbed sleep patterns, scientists in Iceland said in a report published Wednesday.
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.
``The excess of malignant melanoma among those flying over five time zones suggests that the importance of disturbance of the circadian rhythm should be taken into consideration in future studies,'' Dr Vilhjalmur Rafnsson told Reuters.
Circadian rhythms regulate sleep patterns and the hormone melatonin, a chemical naturally released by the brain to induce sleep.
``Melatonin is something that inhibits the growth of cancer cells in experimental models. 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.
``It could be a combination of bad habits (such as sunbathing) and melatonin. The next thing to do is to study larger groups of pilots and whether they are sunbathing all the time,'' he said.
Rafnsson and his colleagues looked at the skin cancer rates of 265 pilots who worked for Icelandic airlines and compared them with rates expected to develop in the general population based on data from the national cancer registry of people of the same age.
Their research is published in the journal Occupational and Environmental Medicine.
The pilots had higher rates of malignant melanoma than any other cancer. Rates for pilots flying international routes were 15 times higher than expected and 25 times higher for pilots flying routinely from Iceland to the United States.
The pilots' estimated dose of annual radiation was well within accepted levels for occupational exposure.
Melanoma accounts for about 10 percent of all skin cancers but causes 75-85 percent of skin cancer deaths. Excessive exposure to harmful sun rays can increase the risk of the disease.
Previous research by Danish scientists showed that long-serving pilots and cabin crew also had a higher risk of leukemia, which scientists believe could be due to increased exposure to cosmic radiation.
Beta Carotene Does Not Protect Against Skin Cancer
NEW YORK (Reuters Health) -- Beta carotene does not protect humans from developing nonmelanoma skin cancer, report US researchers.
Previous study findings suggested that beta carotene supplements did protect against basal cell and squamous cell skin carcinomas in mice. But a report in the February issue of the Archives of Dermatology shows that men who took beta carotene supplements for 12 years had the same risk of such skin cancers as men who did not take the supplements.
Researchers led by Dr. Uta M. Frieling of Harvard Medical School in Boston, Massachusetts, evaluated the effect of taking beta carotene every other day on the development of nonmelanoma skin cancer among more than 22,000 male physicians, taking part in the Physicians' Health Study, which began in 1982 and ended in 1995.
The men were randomly assigned to take either 50 milligrams of beta carotene or (an inactive) placebo every other day, and to take either 325 milligrams of aspirin or placebo on alternate days.
A total of 3,607 of these men developed nonmelanoma skin cancer, 1,786 in the beta carotene group and 1,821 in the placebo group. Taking the antioxidant supplement did not make any difference in the risk of these skin cancers, nor did it cause any harmful side effects. The authors also report that smoking status did not affect the development of these skin cancers.
Frieling and colleagues offer several explanations for why beta carotene did not protect participants in their study from skin cancer. They note, for example, that some studies have found that the supplement gives more protection to those who have lower blood levels of it to start with. The current study did not look at baseline levels of beta carotene, so they can't test this hypothesis.
The researchers conclude that people should not count on nutritional supplements to protect them against cancers caused by exposure to the sun. Instead, they need to reduce their risk by limiting their exposure.
In an accompanying editorial, Dr. John A. Baron of the Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, notes that although animal studies and epidemiological surveys suggested that beta carotene offers protection against skin cancer, clinical trials have failed to show any effect.
``Results from randomized trials of beta carotene for cancer prevention should raise troubling issues for scientists who wish to base health recommendations on epidemiological or laboratory data,'' Baron concludes. He states that animal studies can help us understand disease processes, but the relevance of these studies to the prevention of human cancer ``remains doubtful.'' Instead, recommendations for humans must come from carefully structured clinical trials. SOURCE: Archives of Dermatology 2000;136:179-184, 245-246.
From Dallas <
Hello Jeff Rense,
I wrote to you recently in praise of you and your website and I see that you're still maintaining the high quality of articles and guests.
I just wanted to throw in my two cents about the article from Iceland about pilots and skin cancer. I am a private pilot and have been an Airline Mechanic (Eastern Air Lines & Pan American) for 12 years. What the scientists always forget about Airline flight (33,000 ft.) is that it takes you above the heavier lower atmosphere that general aviation (5,000 ft.) and corporate aviation (22,000 ft.) usually fly through. The little acknowledged studies point to high energy cosmic and gamma radiation penetrating the fuselage. Also soft x-rays and high energy ultraviolet B.
As a mechanic I know what's behind the plastic liners inside the plane and there is nothing but fiberglass in aluminum blankets to keep the heat in. The Iceland study about pilots having 25 times more skin cancer because they cross many time zones really means that the pilots are in the air for a longer period of time! It is not from sleep disorder. The government would have us not smoke in planes for people's health but a pregnant woman on a long distance flight may harm the baby more from radiation,just by being there, then any amount of smoke from passengers.
As you well know, there are a lot of things that the government is aware of. It just doesn't tell us.
Chris Dadalias
Athens, Greece


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