US pilots and flight attendants face higher cancer death risk tied to cosmic rays

A new study points to an overlooked occupational danger for pilots and flight attendants who appear to face higher death rates from several cancers associated with radiation exposure.

Here's what to know

The finding came from a review of death-certificate data across hundreds of occupations by researchers at Harvard Medical School and other institutions who suspect the source is cosmic radiation from above the plane, which grows stronger at cruising altitude. Even when measured against nuclear technologists — workers who also spend time around ionizing radiation — airline pilots and flight attendants showed higher death rates from several cancers associated with radiation exposure, according to Gizmodo. 

Among the cancers the researchers examined were lymphoma and breast, thyroid, and prostate cancers. They also checked cancers that are not usually linked to radiation, to see whether the elevated risk seemed specific to radiation-related diseases.

Vishal Patel, a physician and health care policy researcher at Harvard and the study's lead author, said one long-running challenge in this research has been making fair comparisons. "Prior studies have generally been cohort studies assembled one airline, one country, or one cancer site at a time," Patel told Gizmodo.

Because U.S. death certificates began routinely recording a person's usual occupation in 2020, researchers were able to make broader comparisons across lines of work.

More background

At high altitude, there is less atmospheric protection from cosmic rays, which can injure cells and raise the odds of harmful mutations. Gizmodo noted that this helps explain why aircrew members in the United States are already considered to have the highest average exposure to ionizing radiation of any occupation.

For most passengers, occasional flying is not the central concern. The bigger issue is cumulative exposure over many years for workers who spend large stretches of their careers in the air, often while dealing with disrupted sleep schedules that could contribute to the health burden.

The researchers also used ground aircrew members as a comparison group. Those workers share some job conditions with flight crews but do not have the same altitude exposure, which strengthened the argument that time spent at cruising height may be an important factor.

What's being done?

The authors say the findings argue for stronger on-the-job protections for pilots and flight attendants, with safety standards focused on the radiation exposure these workers experience.

Patel noted that the Federal Aviation Administration has formally recognized that aircrew are occupationally exposed to ionizing radiation but that the U.S. has not mandated dose limits or any monitoring of these employees — regulations that the European Union has had in place for years for its aircrews, including schedule adjustments during pregnancy.

The next steps will likely depend on how regulators and employers respond, and on whether future studies confirm the same patterns in larger datasets.

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