Flight attendants may have a higher risk of developing several types of cancer — including breast and skin — than the general public, according to a new study.
The study, published Tuesday in Environmental Health, showed that women and men on U.S. cabin crews have higher rates of cancer, and exposure to potential carcinogens, shift work and time-zone changes that disrupt sleep cycles, could be contributing factors.
Between 2007-2015, researchers asked 5,366 flight attendants and 2,729 other adults with similar socioeconomic backgrounds whether they had ever been diagnosed with cancer.
Compared to the other adults, flight attendants were 51 per cent more likely to develop breast cancer. They also had more than double the risk of melanoma and more than quadruple the odds of being diagnosed with other forms of skin cancer.
“This study is the first to show higher prevalences of all cancers studied, and significantly higher prevalences of non-melanoma skin cancer compared to a similarly matched U.S. sample population,” said lead study author Eileen McNeely of the Harvard T.H. Chan School of Public Health in Boston.
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The authors called the differences “striking,” given the low rates of obesity and smoking among flight attendants in the study.
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The researchers also found an association between each five-year increase in time spent working as a flight attendant and non-melanoma skin cancer among women. There was no link identified between job tenure and thyroid cancer or melanoma — the deadliest skin cancer — in women.
Male flight attendants were found to have higher rates of melanoma and non-melanoma skin cancers.
What’s causing the higher rates of cancer?
The research does not answer why flight attendants report higher cancer numbers, but the authors have some theories.
Flight attendants are exposed to several carcinogens in the cabin environment, including cosmic ionizing radiation at flight altitude. Cosmic radiation originates in outer space, but small amounts still reach the earth. The greater chance of exposure comes at higher altitudes.
The study said the exposure may not be harmful to people taking individual flights, but for those whose jobs involve flying, it may have a negative impact on their health.
Other chemical contaminants found in the cabin may include engine leakages, pesticides and flame retardants, which contain compounds that could increase the risk of some cancers, the studies’ authors said.
Exposure to second-hand smoke may also be a cause, the study suggested.
“Many flight attendants working today were also exposed to high levels of second-hand tobacco smoke before in-flight smoking bans were implemented,” the authors said. “The long-term health effects of this mix of occupational exposures, including with regard to cancers which develop over the course of many years, have not been well characterized.”
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Flight attendants also have disrupted sleep schedules as they frequently cross time zones, which disturbs their regular circadian wake-sleep cycle.
Previous studies have linked disrupted sleep cycles to a higher risk of breast and prostate cancer, it can affect genes responsible for repairing DNA, which could lead to more abnormally growing cells that become cancerous.
Limitations to study
The authors noted there were limitations to the study, as researchers were not able to take into consideration individual UV exposures, such as sunbathing habits, which could influence skin-cancer risk.
Cancer rates were also self-reported by study participants, and the diagnosis was not confirmed by a check of medical records.
The authors said the findings show that additional efforts are needed to minimize the risk of cancer among flight attendants, such as monitoring radiation doses (in Europe, flight attendants’ exposure to cosmic ionizing radiation is monitored and limited by law) and protecting against known carcinogens.
— With files from Reuters
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