A new study of nearly 13 million U.S. death certificates has identified flight attendants and pilots as the occupations with the highest and second-highest proportions of radiation-related cancer deaths among more than 500 professions. The findings, published in JAMA Internal Medicine, are drawing attention to the health risks faced by aircrew members, who spend much of their working lives at altitudes where the atmosphere provides less protection from high-energy particles arriving from space. Researchers say the results strengthen the case for treating occupational radiation exposure among U.S. aircrew as a more serious workplace health concern.
The study found that approximately 6.9 percent of deaths among flight attendants and 6.7 percent of deaths among pilots were attributed to cancers considered related to ionizing radiation. Those proportions exceeded the corresponding figures for every other occupation examined in the analysis. The comparison included professions known for exposure to artificial sources of radiation, such as nuclear technologists, who ranked 12th in the study. The researchers cautioned that the results do not prove that cosmic radiation caused individual deaths, but they reveal a population-level pattern that warrants closer investigation.
Aircrew members are exposed primarily to cosmic radiation, a mixture of high-energy protons, atomic nuclei, and secondary particles generated when radiation from the sun and distant astrophysical sources collides with Earth’s atmosphere. At ground level, the atmosphere absorbs much of this energy. Commercial aircraft, however, typically cruise between approximately 30,000 and 40,000 feet, where the protective atmospheric layer is thinner. The result is a greater exposure to ionizing radiation, which carries enough energy to remove electrons from atoms and potentially damage DNA, creating mutations that can contribute to cancer development over time.
According to estimates cited by the researchers and the U.S. Centers for Disease Control and Prevention, pilots and flight attendants receive between 3 and 6 millisieverts of cosmic radiation annually, depending on factors such as flight altitude, route, latitude, and solar activity. A millisievert is a unit used to estimate the biological effect of ionizing radiation. By comparison, an average air traveler taking 10 cross-country round-trip flights each year receives an estimated 0.4 millisieverts. The difference reflects the cumulative nature of occupational exposure: aircrew may fly hundreds or thousands of hours annually, repeatedly passing through regions of elevated radiation.
To investigate whether this exposure was associated with higher cancer mortality, the research team analyzed the National Vital Statistics System, the United States’ central collection of death certificate data. The records had only recently been linked to the occupation of the person who died, allowing the investigators to compare mortality patterns across a much larger occupational population than earlier studies could provide. The dataset covered deaths occurring from 2020 through 2024 and included nearly 13 million decedents across 503 occupations. Among them were approximately 14,000 pilots and 7,000 flight attendants.
The researchers used a common adjustment approach to account for demographic and social factors that can influence both occupation and mortality. Their statistical models considered age at death, sex, race, ethnicity, educational attainment, and marital status. These adjustments are important because occupational groups are not interchangeable: pilots and flight attendants may differ from the general population in age distribution, income, access to health care, smoking patterns, reproductive history, and other variables that affect cancer risk. Even after accounting for the available factors, the aircrew occupations showed unusually high proportions of deaths from several cancers.
The cancers included in the analysis were breast cancer, central nervous system cancers, multiple myeloma, leukemia other than chronic lymphocytic leukemia, lymphoma, thyroid cancer, prostate cancer, melanoma, and non-melanoma skin cancers. Pilots and flight attendants had statistically significantly higher mortality rates from breast cancer, central nervous system cancers, prostate cancer, and melanoma. Pilots also experienced a significantly higher rate of death from leukemia. These results are biologically plausible in some respects, since ionizing radiation can damage DNA throughout the body, although the study was not designed to determine which specific component of aircrew life—cosmic radiation, ultraviolet exposure, disrupted sleep, circadian disturbance, lifestyle, or another factor—was responsible for the observed patterns.
The distinction between cancer incidence and cancer mortality is central to the study. Earlier research has suggested that aircrew members may be diagnosed with certain cancers more often than the general population, but diagnosis does not necessarily translate into a higher risk of death. Survival depends on cancer type, stage at diagnosis, treatment access, screening, and many other factors. By examining death certificates, the new study focused specifically on fatal outcomes. However, death certificate data also have limitations: occupational histories may be incomplete or inaccurately recorded, causes of death can be misclassified, and the records do not contain detailed information about flight hours, routes, cumulative radiation dose, smoking, alcohol use, reproductive factors, or personal medical history.
The findings arrive as U.S. regulators formally recognize pilots and flight attendants as workers occupationally exposed to ionizing radiation, while stopping short of imposing the dose limits and routine monitoring requirements applied to many other radiation-exposed employees. In several other countries, air carriers and aviation authorities use measures such as dose estimation, route assessment, and special protections for pregnant crew members. The researchers argue that the elevated cancer mortality proportions observed in their analysis support reconsideration of whether U.S. aircrew protections should be aligned more closely with the level and duration of their exposure. Such measures could include improved exposure tracking, targeted health surveillance, and greater attention to flight scheduling and high-radiation routes.
The authors emphasize that their analysis demonstrates an association rather than direct causation. Cosmic radiation is a credible occupational hazard, but commercial aviation also involves unusual schedules, nighttime work, sleep disruption, ultraviolet exposure during flight, frequent travel across time zones, and other conditions that may influence long-term health. Determining the contribution of each factor will require studies that follow workers over time and measure individual exposure more precisely. Even so, the scale of the new analysis gives the signal unusual statistical weight. With air travel continuing to expand and aircrew accumulating repeated exposure over decades, the results are likely to intensify debate over whether the invisible radiation encountered above the clouds should be treated as a routine occupational risk or as a preventable workplace hazard.
Subject of Research: Cancer-related mortality and occupational exposure to cosmic ionizing radiation among U.S. pilots and flight attendants.
Article Title: Cancer-Related Mortality Among US Pilots and Flight Attendants
News Publication Date: 17-Aug-2026
Web References: https://doi.org/10.1001/jamainternmed.2026.3635
References: JAMA Internal Medicine, DOI: 10.1001/jamainternmed.2026.3635; U.S. Centers for Disease Control and Prevention estimates on cosmic-radiation exposure during air travel.
Keywords: pilots, flight attendants, aircrew, cosmic radiation, ionizing radiation, occupational exposure, cancer mortality, leukemia, melanoma, breast cancer, prostate cancer, aviation health, radiation protection
Tags: cancer mortality among aircrewcosmic radiation exposure and cancer riskhealth risks for pilots and flight attendantshigh-altitude cosmic radiation effectsionizing radiation and cancerlong-term health impacts of aviation radiationoccupational exposure to cosmic radiationoccupational health study on airline staffradiation-related cancer risk for airline crewregulatory considerations for airline occupational safetyworkplace health concerns in aviation industryworkplace safety for flight crew
