UNITED STATES, Aug. 19 (Nationwide Times) — For most airline passengers, the findings do not establish a new personal cancer danger from occasional flying. The study focused on people who worked for years as pilots or flight attendants, and it found an association—not proof that flying-related radiation caused their deaths.
The research, published Aug. 17, 2026, in JAMA Internal Medicine, analyzed nearly 13 million U.S. death certificates covering 503 occupations from 2020 through 2024, according to Harvard Medical School. About 14,000 pilots and 7,000 flight attendants were included.
Among the occupations studied, flight attendants had the highest share of deaths linked to cancers classified as radiation-related. Pilots had the second-highest share. The share was 6.9% for flight attendants and 6.7% for pilots, based on the study’s analysis of National Vital Statistics System records.
Those figures are proportions of deaths in the occupational groups, not the chance that an individual worker will develop cancer. The study’s reports did not provide the absolute cancer mortality rates or the number of deaths from each cancer among pilots and flight attendants. That makes it difficult to translate the percentages into a personal risk estimate.
Why might aircrew face more radiation exposure?
At commercial flight altitudes, workers are exposed to cosmic radiation, a form of ionizing radiation that comes from space. The Centers for Disease Control and Prevention estimates cited in coverage of the study put annual exposure for U.S. airline workers at about 3 to 6 millisieverts. By comparison, 10 round-trip cross-country flights would involve about 0.4 millisieverts, according to the same CDC comparison.
The difference is mainly the length and frequency of exposure. A passenger may fly occasionally, while aircrew members can spend many hours in the air over years of work. 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 at commercial flight altitudes.
Harvard senior author Anupam Jena said the findings support considering occupational radiation protections for U.S. aircrew members that match their level of exposure.
Which cancers were linked to the occupations?
The study grouped breast cancer, melanoma and non-melanoma skin cancers, leukemia excluding chronic lymphocytic leukemia, lymphoma, multiple myeloma, thyroid cancer, prostate cancer and cancers of the central nervous system as radiation-related.
Pilots and flight attendants had significantly higher mortality rates for breast cancer, central nervous system cancers, prostate cancer and melanoma, according to reports on the study. Pilots also had higher leukemia mortality.
The pattern was not seen across all cancers. For cancers classified as non-radiation-related, mortality among pilots and flight attendants was comparable with that of other occupations. Ground-based aviation workers also did not show the same pattern described for aircrew.
What the study cannot show
The research was observational. That means it compared patterns in existing records; it did not assign people to jobs or measure their exposure over time. The design can identify an association, but it cannot establish that cosmic radiation caused the higher cancer mortality.
The available study summaries do not show whether occupation referred to a person’s current or lifetime job, how factors such as smoking were handled, or whether researchers had records of individual flight hours and radiation doses. Those details matter because cancer has many possible causes, and workers in one occupation may differ from workers in another in ways unrelated to radiation.
The study also examined deaths, not all cancer diagnoses. A death-certificate analysis can show which cancers were recorded among people who died, but it does not by itself measure the total number of workers who developed cancer and survived.
How this fits with other occupation research
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. Researchers from Ohio State University, the University of Washington and other institutions calculated age-adjusted cancer mortality rates by sex for more than 400 occupations.
That research, summarized by the University of Washington School of Public Health, also found that cancer mortality differs among occupations. But the two studies answer different questions: the aircrew study focused on the proportion of deaths classified as radiation-related, while the Lancet Oncology study examined broader cancer mortality patterns.
Taken together, the findings point to occupational exposures as an area for further study and possible workplace protections. They do not show that every pilot or flight attendant will develop cancer, nor do they establish that occasional air travel creates the same exposure pattern as working in aviation. For individual medical decisions, the studies do not replace advice from a qualified clinician.
