Study Links Cosmic Radiation to Higher Cancer Death Risk in Flight Crews
Flight attendants and pilots are at the highest risk of dying from radiation-related cancers, according to a new study published in JAMA Internal Medicine. The findings indicate that these aviation professionals face greater risks than even those who work directly with radioactive materials.
Cosmic radiation originates from space, and while only a small amount reaches Earth's surface, exposure is significantly higher at the altitudes where commercial flights operate. Previous research had offered limited evidence from small studies suggesting a link between frequent flying and increased cancer death rates, but the new study provides a more comprehensive look.
Comprehensive Analysis of Death Records
The study, released Monday, analyzed national data from more than 12 million death certificates that included occupational information. Researchers focused on cancers known to be associated with radiation exposure, including leukemia, lymphoma, multiple myeloma, and cancers of the skin, breast, thyroid, prostate, and central nervous system.
Among more than 500 occupations studied, flight attendants had the highest percentage of deaths from radiation-related cancers, with pilots ranking second. For both occupations, the odds of dying from each type of radiation-related cancer were unusually high. Importantly, neither group showed elevated death rates from cancers not linked to radiation exposure.
This pattern, according to Catherine Olsen and Ken Karipidis, Australian radiation experts who wrote an accompanying commentary, "supports the hypothesis that occupational radiation exposure, rather than lifestyle or socioeconomic factors, underlies the observed excess." They noted that the study "brings important new evidence to bear on this question."
Quantifying the Risk
The researchers found that flight attendants had about 50% higher odds of dying from a radiation-related cancer compared to the general working population, while pilots had about 36% higher odds. In absolute terms, 6.9% of flight attendant deaths were attributed to these cancers—roughly 1 in 14—with pilots at 6.7% and the general working population at 5%.
Dr. Vishal Patel, the study's first author from Harvard Medical School, acknowledged limitations, including unknown individual exposure levels and possible occupational misclassification on some death certificates. The authors also could not account for disruption of the body's internal clock due to jet lag, crossing time zones, and irregular schedules, which may contribute to cancer risk.
Calls for Action and Monitoring
The study has prompted calls for greater attention to the risks faced by aviation crews. Dr. Patel emphasized the need for measurement, stating in an email, "You can't manage an exposure you've decided not to measure." The Federal Aviation Administration has acknowledged that aircrews are exposed to ionizing radiation but has not set federal dose limits or required monitoring.
Sara Nelson, president of the Association of Flight Attendants-CWA, which represents 55,000 flight attendants, said the report reinforces that radiation exposure needs to be taken seriously. "The risk is known, but crew are not educated or informed. And, no one is taking responsibility," she said.
The commentary writers suggest that annual skin examinations may be warranted for all people working on high-altitude flights, and women in those jobs may want to consider mammograms earlier or more frequently. They also advise doctors caring for pilots and flight attendants to maintain a "heightened index of suspicion" for cancer when evaluating these patients.
While the study's findings are significant, the absolute risk remains relatively low, with around 1 in 14 flight attendant deaths and 1 in 15 pilot deaths linked to radiation-related cancers. The research adds to the growing body of evidence that occupational cosmic radiation exposure poses a real health concern for those who spend significant time in the air.