Pilots and flight attendants in the U.S. face the highest risk of radiation related cancer deaths among more than 500 occupations examined in a new Harvard study, according to study author Anupam B. Jena, M.D., Ph.D.

The research suggests that people who fly for a living could face a higher risk of certain cancers. However, the observational findings show an association and cannot establish that exposure to cosmic radiation caused the elevated cancer mortality.

“As you get high up in the atmosphere, you're exposed to ionizing radiation from the sun. It's called cosmic radiation,” Jena told Fox News Digital.

Researchers based their findings on an analysis of data from the National Vital Statistics System. The data included nearly 13 million U.S. death certificates from 2020 through 2024, including records for 14,000 pilots and 7,000 flight attendants.

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The team examined mortality involving radiation related cancers across all occupations. Those cancers included breast cancer, multiple myeloma, leukemia except chronic lymphocytic leukemia, lymphoma, central nervous system cancers, thyroid cancer, prostate cancer, melanoma and non melanoma skin cancers.

Lung cancer was not included in the analysis because researchers wanted to prevent any smoking related risk from confounding the results. The focus therefore remained on the cancers identified by the researchers as related to radiation.

Pilots and flight attendants had statistically significantly higher mortality rates linked to breast cancer, central nervous system cancers, prostate cancer and melanoma. Pilots were also more likely to die from leukemia, according to the findings.

Among all deaths of flight attendants, 6.9% were linked to radiation related cancers. The corresponding figure among pilots was 6.7%, and both rates were higher than those recorded for any other occupations in the analysis.

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At the same time, mortality rates for cancers not related to radiation were comparable with those in other occupations. Jena said that distinction suggests the results were not simply reflecting a higher likelihood of developing cancer overall.

“It's not just lifestyle factors or factors about these individuals that are making them more likely to develop cancer at large,” Jena said.

The study was published Aug. 17 in JAMA Internal Medicine. Jena emphasized that its findings apply to pilots and flight attendants as occupational groups rather than determining the risk faced by any particular worker.

“The risk increase is meaningful enough for the group,” he said. “Our study doesn't speak to the individual pilot or flight attendant, but more so to the two groups as a whole.”

Airline workers receive about 3 to 6 millisieverts of cosmic radiation each year, according to the Centers for Disease Control and Prevention. Someone taking 10 round trip flights across the country receives about 0.4 millisieverts.

That comparison means airline workers may receive roughly eight to 15 times the annual cosmic radiation exposure of someone taking 10 round trips across the country. Jena said the potential risk is thought to accumulate as exposure continues.

“It is thought that this would be a cumulative risk, so the more time that you're exposed to that cosmic radiation, the greater the increase in risk that you might experience,” he said.

The findings could raise questions about whether pilots and flight attendants in the U.S. should receive additional cancer screenings or begin screenings earlier. Jena noted that screening approaches differ between the U.S. and other countries.

“I think the level of screening may need to be higher,” Jena said. He also said regular screening and the possibility of beginning it earlier in life are considerations for these workers.

For people who fly frequently for business or pleasure, Jena said the findings should be less concerning. Very few passengers accumulate an amount of flight time comparable to that of pilots and flight attendants.

“This is really sort of a consideration for people who spend their life in the air,” he said.

The study also had important limitations. Researchers lacked data about the radiation exposure of individual workers, so they could not determine whether workers with greater exposure experienced greater risks.

Because the research was observational, it could identify only an association between the occupations and elevated cancer mortality. Other occupational or lifestyle factors could also potentially have contributed to the findings.