Workers in nuclear plants or X-ray suites might seem most exposed to harmful radiation, but new evidence points to a very different high-risk group. Among more than 500 occupations assessed in a major US study, flight attendants and pilots show the highest share of deaths from radiation-related cancers.
The analysis, published in JAMA Internal Medicine, examined how often specific cancers linked to ionizing radiation appeared as a cause of death in different jobs. Researchers found that no other profession accounted for a higher proportion of radiation-related cancer mortality than flight attendants, with pilots coming second.
Cosmic rays at cruising altitude
The key driver is exposure to cosmic rays at high altitude, where Earth’s atmosphere offers less protection from high-energy particles from space. The higher an aircraft flies and the longer it remains in the air, the more radiation accumulates, especially on polar routes where shielding from Earth’s magnetic field is weaker.
According to the authors, led by Harvard Medical School researcher Vishal Patel, aircrew members receive the largest average annual dose of ionizing radiation of any US occupational group. Pilots and flight attendants are estimated to absorb 3 to 6 millisieverts per year, far above the roughly 0.4 millisieverts received by a frequent flyer taking 10 long-haul round trips annually.
What the mortality data shows
To quantify risk, the team used US National Vital Statistics System data from death certificates for 12.7 million people who died between 2020 and 2024. Each person’s main lifetime occupation was recorded and grouped into 503 job categories, allowing comparisons across a broad swath of the workforce.
Researchers separated cancer deaths into two groups: those from malignancies known to be associated with ionizing radiation and those from cancers not typically linked to such exposure. Radiation-related cancers included breast, thyroid and prostate cancers, melanoma, multiple myeloma and several leukemias and lymphomas.
In this ranking, flight attendants had the highest proportion of deaths from radiation-related cancers, and pilots the second highest, outpacing nuclear medicine technologists and other medical imaging staff. For cancers not associated with radiation, however, both aircrew groups clustered close to the median compared with other occupations.
Overall, the study estimates that flight attendants were about 50 percent more likely to die from radiation-related cancers than the average across all occupations. Pilots were roughly 36 percent more likely. The findings highlight that the elevated risk appears specific to radiation-linked cancers rather than a general increase in cancer mortality.
Cosmic rays, UV and body clocks
The research cannot definitively prove that cosmic radiation directly caused the additional cancers in aircrew, but independent experts say the pattern is consistent with that explanation. In a commentary, epidemiologists Catherine Olsen and Ken Karipidis argued that the specificity of the excess points toward occupational radiation rather than lifestyle or income differences.
They also noted that cosmic rays may be only part of the picture. UV radiation penetrating cockpit and cabin windows could raise skin cancer risks, especially for pilots who sit closer to large front windows. Chronic disruption of circadian rhythms from night flights and irregular schedules is another possible contributor to cancer risk.
Previous studies have found higher rates of melanoma and breast cancer among pilots and cabin crew, particularly on long-haul and high-latitude routes. The new work, using a large, recent mortality dataset across many occupations, strengthens that body of evidence and underscores aviation as a unique environment for radiation exposure.
Regulation and protection gaps
In the US, the Federal Aviation Administration recognizes pilots and flight attendants as workers occupationally exposed to ionizing radiation. However, unlike nuclear power staff or radiology technicians, they are not currently subject to federal dose limits or routine radiation monitoring requirements.
The authors suggest that occupational health policies for US aircrew lag behind those in parts of Europe, where airlines often track crew radiation doses and plan schedules to keep long-term exposure within recommended limits. Tools already exist to estimate dose per flight based on altitude, route and solar conditions.
Experts say more proactive medical surveillance could help, such as incorporating years of high-altitude service into risk assessments during check-ups. Regular skin examinations, breast screening for female crew and clear guidance on sun protection and shift patterns may all reduce long-term cancer risk.
For passengers, the data remain more reassuring. Even frequent leisure or business travelers typically accumulate far lower doses than full-time crew, and their cancer risk increase appears modest. The study reinforces that occupational exposure over many years, rather than occasional flying, is the main concern.
The findings also arrive as the aviation sector explores higher-altitude and potentially suborbital flights, which could increase radiation exposure further. Researchers say more work is needed to understand how solar storms and newly identified radiation clouds might affect both crew and frequent flyers in the years ahead.
The authors conclude that aircrew should receive occupational protections proportionate to their exposure, similar to other radiation-exposed groups. As commercial aviation continues to expand, the study argues that making the skies safer for those who work in them every day will require updated regulations, better monitoring and continued research into long-term health impacts.
