UNITED STATES, Aug. 19 (Nationwide Times) — For most people who fly, the findings do not mean that an occasional flight creates a major cancer threat. The study instead points to a possible occupational concern for people who spend years working at high altitudes, where exposure to cosmic radiation is greater than on the ground.
A study published in JAMA Internal Medicine examined nearly 13 million U.S. death certificates from 2020 through 2024. It compared cancer mortality across 503 occupations, including about 14,000 pilots and 7,000 flight attendants.
Among the occupations studied, flight attendants had the highest share of deaths linked to the study’s radiation-related cancer categories. Pilots had the second-highest share. Radiation-related cancers made up 6.9% of deaths among flight attendants and 6.7% of deaths among pilots, according to the study’s analysis of National Vital Statistics System records.
Those percentages describe the share of deaths in each occupation, not the chance that an individual worker will develop cancer. The study did not provide the absolute cancer risk for an individual pilot or flight attendant.
Why aircrew members may have more exposure
Cosmic radiation is high-energy radiation from space. The atmosphere shields people from much of it, but that protection is thinner at commercial flight altitudes. The study authors wrote that aircrew members receive the highest average annual dose of ionizing radiation of any U.S. occupational group, largely because of cosmic rays encountered during flights.
The Centers for Disease Control and Prevention has estimated that U.S. airline workers receive about 3 to 6 millisieverts of cosmic radiation each year, according to figures cited in coverage of the study. For comparison, someone taking 10 round-trip cross-country flights would receive about 0.4 millisieverts, according to the same comparison.
The amount of exposure can vary with factors such as time spent in the air, flight routes and altitude. The available study summary did not provide individual workers’ flight hours or radiation doses.
Which cancers were linked to aircrew jobs?
The study grouped several cancers as radiation-related. The categories included breast cancer, melanoma, leukemia excluding chronic lymphocytic leukemia, lymphoma, multiple myeloma, thyroid cancer, prostate cancer, central nervous system cancers and non-melanoma skin cancers.
Pilots and flight attendants had significantly higher mortality rates for breast cancer, central nervous system cancers, prostate cancer and melanoma, according to the study. Pilots also had higher leukemia mortality.
The pattern was different for cancers classified as non-radiation-related. Mortality rates for pilots and flight attendants were comparable with those in other occupations, and the aircrew results were near the middle of the occupation rankings. The study authors said the contrast supports further study of workplace exposures, but it does not prove that cosmic radiation caused the cancer deaths.
What the study can — and cannot — show
The research was observational. That means it looked for patterns in existing records rather than assigning people to jobs or exposures. Such a study can identify an association, but it cannot establish cause and effect.
Death certificates also have limits. The available summary does not show whether the occupation listed was a person’s current job or a lifetime occupation. It also does not provide full details on smoking, other health factors, years of employment or the statistical adjustments used in the analysis.
For that reason, the findings should not be read as a prediction of an individual worker’s outcome. They also do not show that every cancer death among an aircrew member was caused by workplace radiation.
Harvard Medical School senior author Anupam Jena said the results support considering occupational radiation protections for U.S. aircrew members that match their level of exposure. Any changes to workplace rules would require evaluation by relevant public-health and occupational-safety agencies.
A broader question about jobs and cancer
The aircrew study is part of a larger body of research examining whether workplace conditions affect cancer mortality. A separate study published in January 2026 in The Lancet Oncology analyzed nearly 500,000 cancer deaths among working-age U.S. adults from 2020 through 2023 and calculated age-adjusted cancer mortality rates by sex for more than 400 occupations. Researchers from Ohio State University and the University of Washington were part of that study.
Earlier research has also reported links between some occupations and specific cancers, although findings have varied by job, cancer type and study design. A 1995 study, for example, reported higher breast-cancer risks in several occupations, including nursing, teaching, social work, secretarial work and meat cutting.
Together, these studies can help researchers identify workplaces that deserve closer examination. They do not mean that a job title alone determines a person’s cancer risk. Individual risk is also shaped by factors such as age, family history, tobacco use, medical history and exposures outside work, none of which can be fully captured by the occupation comparisons in the aircrew study.
