UNITED STATES, Aug. 19 (Nationwide Times) — A large U.S. study found that flight attendants and pilots had the highest and second-highest shares of radiation-related cancer deaths among 503 occupations. The finding points to a possible workplace concern for aircrew members, but it does not show that flying caused the cancers or that occasional air travel raises a person’s cancer risk.
The study, published Aug. 17, 2026, in JAMA Internal Medicine, analyzed nearly 13 million U.S. death certificates from 2020 through 2024. The records included about 14,000 pilots and 7,000 flight attendants, according to Harvard Medical School, which summarized the research.
Among deaths recorded for flight attendants, 6.9% were linked to cancers included in the study’s radiation-related category. The figure for pilots was 6.7%.
Those figures describe the share of deaths in each occupation, not the chance that an individual worker will develop cancer. The study’s reported results also do not provide absolute cancer mortality rates for aircrew, so they cannot show how large the excess risk was in everyday terms.
Why might aircrew face more exposure?
At commercial flight altitudes, workers are exposed to cosmic radiation, a form of ionizing radiation that comes from space. The study authors wrote that aircrew members receive the largest average annual dose of ionizing radiation of any U.S. occupational group, primarily because of cosmic rays encountered during flights.
The study reports that U.S. airline workers receive about 3 to 6 millisieverts of cosmic radiation each year. A comparison cited in the study’s coverage estimates that 10 round-trip cross-country flights would expose a person to about 0.4 millisieverts. The Centers for Disease Control and Prevention was identified as the source of those exposure figures.
Because pilots and flight attendants can spend many hours in the air over years of employment, their occupational exposure differs from that of passengers who fly occasionally. The study did not examine occasional travelers as a separate group.
Which cancers were linked to the occupations?
The researchers classified several cancers as radiation-related, including breast cancer, leukemia, melanoma, thyroid cancer, prostate cancer, multiple myeloma, lymphoma, central nervous system cancers and non-melanoma skin cancers.
Pilots and flight attendants had statistically higher mortality rates for breast cancer, central nervous system cancers, prostate cancer and melanoma, according to summaries of the study. Pilots also had higher leukemia mortality.
The pattern was not seen across all cancers. For cancers classified as non-radiation-related, the mortality rates for pilots and flight attendants were comparable with those in other occupations and were near the middle of the occupational rankings.
The researchers also reported that ground-based aviation workers did not show the same pattern as aircrew members. That comparison supports the possibility that an exposure associated with flight, such as cosmic radiation, may be relevant, but it does not prove a cause.
What does the study prove?
It does not prove that cosmic radiation caused the higher cancer mortality. The research was observational, meaning it compared patterns in existing records rather than assigning workers to different levels of radiation exposure.
The available summaries do not provide the study’s full statistical methods, confidence intervals, adjusted mortality ratios or details about how factors such as smoking, age, sex, years on the job and individual flight hours were handled. The records also may not show a worker’s full employment history. Those limits make it difficult to determine how much of the difference was related to radiation rather than other characteristics of the workers or their jobs.
Harvard senior author Anupam Jena said the findings support considering “occupational radiation protections for U.S. aircrew members commensurate with their level of exposure.” That is a workplace-policy issue, not a recommendation in the study for the general public to avoid flying.
How does this fit into wider research?
The aircrew study is part of a broader effort to examine how work may affect cancer mortality. A separate study published in January 2026 in The Lancet Oncology examined nearly 500,000 cancer deaths among working-age U.S. adults from 2020 through 2023 and calculated age-adjusted mortality rates by sex for more than 400 occupations. Researchers from Ohio State University and the University of Washington were among the study team.
That research found that cancer mortality patterns differed by occupation and sex, according to a University of Washington summary. Co-author Marissa Baker said the findings were evidence that some jobs may increase cancer risk, while noting that occupations are not all alike in their exposures and conditions.
Together, the studies show why occupation can be useful when researchers investigate cancer patterns. They do not mean that every worker in a particular job will develop cancer, nor do they establish that one workplace exposure is responsible for every difference.
For aircrew members, the new findings raise questions about monitoring and occupational protections. For people who do not work in aviation, the study’s results do not by themselves establish a reason to change routine travel or other daily decisions. The researchers’ main conclusion concerns a possible workplace risk that needs further study, not an immediate public health alarm.
