Flight attendants and pilots account for a higher share of deaths from radiation-related cancers than workers in any of the other 501 US occupations examined in a new analysis, including people whose jobs involve handling radioactive materials. The study, led by Vishal Patel of Harvard Medical School and Brigham and Women's Hospital, was published in JAMA Internal Medicine and drew on more than 12.7 million US death certificates from 2020 through 2024 that had been linked to each decedent's usual occupation.
Among all 503 occupations, flight attendants ranked first and pilots second. Radiation-related cancers accounted for 6.9 percent of deaths among flight attendants and 6.7 percent among pilots after adjustment for age at death, sex, race, ethnicity, education, and marital status, a share that exceeded that of nuclear technologists. The pattern held for both sexes, with the highest figures among female pilots (8.1 percent) and female flight attendants (7.8 percent).
The cancers examined were those with established links to radiation exposure, including leukemia, lymphoma, multiple myeloma, and cancers of the skin, breast, thyroid, prostate, and central nervous system. The analysis covered 14,190 pilots and 7,170 flight attendants.
The Comparison Groups That Make the Pattern Persuasive
The design choice that gives this analysis its weight is what the researchers looked for and did not find.
Neither aircrew group showed elevated death rates from cancers that are not linked to radiation; on that measure, they sat near the middle of all occupations. Catherine Olsen and Ken Karipidis, two Australian radiation experts who were not involved in the research, wrote in an accompanying commentary that the study "brings important new evidence to bear on this question." They argued that the absence of a signal in non-radiation cancers points toward occupational radiation exposure rather than lifestyle or socioeconomic factors as the explanation for the excess.
The researchers also examined aviation workers who stay on the ground, including 22,355 aircraft mechanics and 664 assemblers. If something about the aviation industry other than flying explained the excess, those workers should have shown it too. They did not. Nuclear technologists, used as a positive control, ranked twelfth.
Cosmic radiation is the proposed mechanism. It streams in from the sun and from deep space, and the atmosphere blocks most of it at ground level. Commercial jets cruise above 30,000 feet, where thinner air provides less shielding. Aircrew absorb more ionizing radiation on the job, on average, than workers in any other US occupation, a point reflected in NIOSH guidance on aircrew and cosmic ionizing radiation.
The Limits Sit Inside the Data Source
Death certificates are the study's foundation and its main constraint, and this should be understood before the ranking is considered settled.
A certificate records a usual occupation, not a career history. It does not capture how many years a person flew, on which routes, at what altitudes, or during which periods of solar activity, all of which determine actual dose. There is no individual exposure measurement anywhere in this analysis.
The study reports the share of deaths attributable to a category of cancer within an occupation, which is not the same measurement as the rate at which people in that occupation develop or die from those cancers. Occupations with low death rates from other causes can show a higher proportion of deaths from any given cause.
Confounding is not eliminated, and the authors said so. Aircrew experience circadian disruption from irregular schedules and time zone crossing, along with other in-cabin exposures. NIOSH notes both cosmic radiation and circadian disruption in its own page on cancer in aircrew, and some studies suggest circadian disruption may itself contribute to cancer. The authors also acknowledged that occupations are sometimes recorded incorrectly on death certificates, and that people at higher baseline risk for these cancers might be more likely to work as aircrew.
Prior research has repeatedly documented elevated cancer rates in aircrew without establishing causation. This analysis strengthens the case considerably. It does not close it.
Passengers Are Not the Population at Issue
The study authors addressed this directly and publicly, which is unusual and worth relaying accurately.
Writing in Time, the authors said they are not rethinking their own travel plans and do not think occasional flyers should either. They put the difference in concrete terms: pilots and flight attendants accrue an estimated 3 to 6 millisieverts of cosmic radiation each year, decade after decade, while a traveler taking 10 cross-country round trips a year absorbs roughly 0.4 millisieverts, a comparison drawn from CDC figures on air travel radiation doses.
Frequent business travelers occupy a middle position the data do not resolve. Someone flying weekly for years accumulates meaningfully more exposure than an occasional traveler, but far less than a working crew member, and no occupational category in this analysis captures them.
Pregnancy is the situation where the calculus is most individual. NIOSH reports that first-trimester exposure at or above 0.36 millisieverts may be linked to increased miscarriage risk in flight attendants, and its page on aircrew and reproductive health covers scheduling and other job demands. Pregnant crew members should work through route and schedule questions with an occupational health clinician rather than reasoning from a headline.
What the Finding Argues for Next
The researchers said their results support extending to aircrew the radiation protections given to other exposed workers. That is the policy consequence, and it lands on a real gap.
The Federal Aviation Administration formally recognizes pilots and flight attendants as occupationally exposed to ionizing radiation. Unlike nuclear workers or aircrew in Europe, US crew members are subject to no federal dose limits and no requirement that their exposure be monitored. Whether that changes is a matter for federal regulators, airlines, and unions rather than for individual crew members.
Working aircrew who want to act on this have ordinary options. Skin checks matter given the elevated skin cancer signal, and crew members should mention their occupation to a dermatologist and primary care clinician, since it is relevant context that is easy to omit. Routine screening, recommended by age and sex, remains the baseline. Nobody should pursue additional imaging or testing outside guidelines without a clinical discussion. This article is general information and is not a diagnosis.
Key Questions Answered
What did the study measure? The share of deaths attributable to radiation-related cancers within each of 503 US occupations, using more than 12.7 million death certificates from 2020 through 2024 linked to usual occupation.
How large was the difference? Flight attendants had the highest risk-adjusted share at 6.9 percent, and pilots the second highest at 6.7 percent, exceeding nuclear technologists, who ranked twelfth.
Does this prove cosmic radiation caused the deaths? No. It is an observational analysis without individual exposure measurements. The absence of elevated deaths from non-radiation cancers and from ground-based aviation workers strengthens the case but does not establish causation.
Should frequent flyers be worried? The study's own authors wrote publicly that occasional flyers should not change travel plans. Aircrew accrue an estimated 3 to 6 millisieverts per year over a career, compared with roughly 0.4 millisieverts for a heavy leisure traveler.
Which cancers were included? Leukemia, lymphoma, multiple myeloma, and cancers of the skin, breast, thyroid, prostate, and central nervous system.
Are US aircrew radiation exposures regulated? The FAA recognizes aircrew as occupationally exposed to ionizing radiation, but exposure is not individually monitored or subject to federal dose limits comparable to those for nuclear workers.
What should working crew members do? Keep routine age-appropriate screening current, pay attention to skin changes, and tell clinicians their occupation, since it is relevant context that often goes unmentioned.
