Attention pilots and flight attendants: For your safety, please fasten your seat belts, note the location of the aircraft’s emergency exits -- and be sure to apply plenty of sunscreen to reduce your risk of melanoma.
When it comes to the risks of flying, skin cancer may not be the first health hazard that comes to mind. But a new study in JAMA Dermatology says that pilots are 2.22 times more likely than folks in the general population at large to be diagnosed with melanoma. For members of the cabin crew, the risk was 2.09 times greater.
Melanoma is the sixth most common cancer in the United States, according to the National Cancer Institute. Although other types of skin cancer are diagnosed more frequently, melanoma is more likely to be fatal, the American Cancer Society says. An estimated 76,100 Americans will be diagnosed with melanoma this year, and about 9,710 will die from it.
Dozens of studies have examined melanoma risk in flight crews, since working at 40,000 feet means greater exposure to cosmic rays and ultraviolet radiation. For the new study, researchers from UC San Francisco combed through data on 266,431 participants in 19 published studies to see whether the danger was real -- and if so, how big it was.
They found that for both pilots and flight attendants, the risk of developing melanoma was more than double the risk seen in people who worked on the ground. However, only pilots faced an increased risk of death from the cancer -- their mortality risk was 83% greater than for those in the general population. (For those who worked in the main cabin, the risk of dying from melanoma was actually 10% lower.)
The study authors noted that exposure to cosmic radiation is not likely to be a factor for melanoma. Many studies have measured the cosmic radiation that finds its way into a plane, and the amount is “consistently below the allowed dose limit of 20 mSv/y,” or 20 millisieverts per year. (A typical American is exposed to about 3.6 mSv per year, according to this report from the Environmental Protection Agency.)
UVB radiation probably isn’t the culprit either, since fewer than 1% of this radiation can penetrate aircraft windshields, the researchers wrote.
UVA, on the other hand, can penetrate glass, and the higher a plane flies, the more intense UVA radiation becomes. When planes fly above clouds or snow-covered mountains, they are exposed to even more UVA reflected from below, the researchers wrote. Studies of cells in lab dishes and in animals show that UVA damages DNA, causing the mutations that can lead to cancer.
It’s possible that when they are on the ground, pilots and flight attendants are bigger fans of activities that would increase their risk of melanoma, such as frequenting tanning salons. So far, there’s no hard data suggesting that this is the case, the UC San Francisco researchers wrote.
Instead, they noted that multiple studies have found that the more hours a member of the flight crew spends in the air, the more likely he or she is to be diagnosed with melanoma.