The job that increases cancer risk? New study warns those who work in the air

Pilots and flight attendants may be at an increased risk of mortality from certain types of cancer associated with radiation exposure, according to a new study by researchers from Harvard University.

The researchers examined nearly 13 million death certificates in the United States from the years 2020–2024 and compared more than 500 professions. Among the records examined were about 14,000 pilots and about 7,000 flight attendants. According to the findings, flight crew members exhibited the highest rates of mortality from cancer types defined in the study as radiation-related.

The possible reason is far above the ground. At the altitude where passenger planes fly, crew members are exposed to ionizing cosmic radiation, which originates, among other things, from space and the sun. As altitude increases, the protection provided by the atmosphere decreases and radiation exposure increases.

"When you go high into the atmosphere, you are exposed to ionizing radiation from the sun. It is called cosmic radiation," explained Dr. Anupam Jena, one of the study's authors.

The study examined mortality from several types of cancer linked to radiation exposure, including breast cancer, leukemia, lymphoma, multiple myeloma, thyroid cancer, prostate cancer, central nervous system tumors, and melanoma. Lung cancer was not included in this group to minimize the possibility that smoking would affect the results.

According to the findings, pilots and flight attendants were found to have statistically significantly higher mortality rates from breast cancer, prostate cancer, central nervous system tumors, and melanoma. Among pilots, a higher rate of mortality from leukemia was also found.

In total, 6.9% of deaths among flight attendants and 6.7% of deaths among pilots were linked to the cancer types examined as radiation-related — higher rates than those found in all other professions tested. In contrast, for cancer types not linked to radiation, no similar gaps were found compared to workers in other professions.

The researchers explain that exposure may accumulate over a career. Flight crew members are exposed to a significantly larger amount of cosmic radiation each year compared to average passengers, even those who fly several times a year. "You can think of it as a cumulative risk," explains Jena. "The longer you are exposed to cosmic radiation, the greater the risk you are exposed to."

The findings also raise the question of whether there is a place for earlier or more frequent screening tests among pilots and flight attendants. According to Jena, it may be appropriate to consider closer monitoring of these workers, noting that approaches should differ between the United States and other countries. "You just need to make sure that people who work in aviation professions are getting screened regularly," he says. "And it may be that these screenings should start at a younger age than the rest of the population."

However, the researchers emphasize that the study does not prove that cosmic radiation directly caused the increase in cancer mortality. This is an observational study, so it is possible to point to a link between the profession and mortality rates, but not to establish a causal link.

In addition, the researchers did not have data on the degree of individual radiation exposure for each pilot or flight attendant, so they could not check whether workers who flew more hours or for more career years were also those who suffered from a higher risk. Other factors related to lifestyle or working conditions may also influence the results.

For regular passengers, even those who fly frequently for work or vacation, the researchers emphasize that the findings should not cause similar concern. According to Jena, very few passengers accumulate a number of flight hours that approaches that of pilots and flight attendants. "It's really a consideration that concerns people who spend their lives in the air," he said.