NEW YORK – Flight attendants and pilots had the highest proportions of deaths from cancers associated with ionizing radiation among more than 500 occupations examined in a large U.S. study, renewing calls for stronger monitoring of cosmic-radiation exposure in aviation.
The analysis, published in JAMA Internal Medicine, used information from about 12.7 million death certificates and compared 503 occupations. Researchers classified a group of cancers with established links to radiation, including certain breast, thyroid, prostate, blood, skin and central nervous system cancers.
About 6.9% of deaths among flight attendants and 6.7% among pilots were attributed to cancers in that radiation-related group, according to the study. After adjustments, flight attendants had roughly 50% higher odds and pilots about 36% higher odds of dying from one of those cancers than the general working population. Nuclear medicine technologists ranked lower in the occupational comparison.
The likely exposure of concern is cosmic radiation, high-energy particles that reach Earth from the sun and deep space. The atmosphere blocks much of that radiation at ground level, but protection decreases at the altitudes used by commercial aircraft. Exposure can be higher on long flights, polar routes and during periods of elevated solar activity.
Lead researcher Dr. Vishal Patel of Harvard Medical School estimated that pilots and flight attendants may receive about 3 to 6 millisieverts of cosmic radiation a year. By comparison, a traveler taking 10 cross-country round trips would receive about 0.4 millisievert, the researchers wrote. The dose can accumulate across a career spent in the air.
The findings do not prove that radiation caused any individual cancer death. Death certificates can contain errors, and the study did not have each worker’s flight hours, routes, career duration, smoking history, family history or other personal risk factors. Researchers tested the pattern by examining cancers not linked to radiation and workers such as aircraft mechanics who spend time around airplanes but do not accumulate flight hours; those comparison groups did not show the same elevation.
The Federal Aviation Administration recognizes aircrews as occupationally exposed to ionizing radiation and provides educational material, but the United States does not impose the same routine dose limits and monitoring requirements used for some other radiation workers or for flight crews in several other countries.
Researchers said the results support considering protections proportionate to aircrews’ exposure. Possible approaches include individual dose estimates based on schedules and routes, education about pregnancy-related exposure, monitoring during solar events and work practices that limit unnecessary accumulation.
Flight crews and frequent travelers should not interpret the study as a reason to avoid medically necessary travel or assume a cancer diagnosis was caused by flying. It is population-level evidence that identifies an occupational pattern and a need for further research, monitoring and risk-reduction policy.
Source: Vice, published Aug. 19, 2026. Additional verification: JAMA Internal Medicine study summary and Harvard Medical School reporting.
