A large US analysis published in JAMA Internal Medicine has identified an elevated proportion of deaths from radiation-related cancers among commercial pilots and flight attendants, raising questions about whether current screening practices sufficiently protect aircrew.
Findings from death-certificate analysis
Researchers from Harvard used US death-certificate data spanning 2020 to 2024 to compare cancer-attributed deaths across 503 occupations. The dataset comprised about 12.7 million deceased people. Among occupations examined, the study reported that:
- Flight attendants had the highest risk-adjusted share of deaths from radiation-associated cancers at 6.9%.
- Pilots had the second-highest share at 6.7%.
- By contrast, aircraft assemblers and mechanics — who work with planes but do not frequently fly — did not show an increased risk.
- Nuclear technologists, a group with recognised occupational radiation exposure used as a positive control, ranked 12th for radiation-related cancer deaths.
The occupational groups of interest included just over 14,000 pilots and more than 7,000 flight attendants among the decedents analysed.
“Specificity of these findings to aircrew suggests an association between large, cumulative in‑flight cosmic radiation exposure and a heterogeneous group of radiation‑related cancers,” the study's corresponding author, Anupam B. Jena of Harvard's Department of Health Care Policy, and colleagues concluded.
What drives the increased risk?
The authors note that commercial aircrew receive higher average occupational doses of ionising radiation than almost any other profession, mainly because of cosmic rays encountered at typical cruising altitudes. The study compared aircrew with both a positive control (nuclear technologists) and a negative control (aircraft assemblers and mechanics) to help distinguish risks related to flying itself from risks related to working around aircraft.
The analysis found the elevated percentage of radiation-related cancer deaths to be specific to those who spend extended time at altitude — a pattern that the researchers interpret as consistent with a dose–response relationship tied to cumulative in‑flight cosmic radiation exposure.
Implications for screening and occupational health
Authors and commentators flagged consequences for screening strategies, particularly for female aircrew. The report highlights that prevailing breast‑cancer screening guidelines may underestimate individual risk for women with long tenures in the aircrew workforce, suggesting a need to consider earlier or more frequent mammographic surveillance for some workers.
For airlines, regulators and occupational-health providers the study raises practical questions:
- Should aviation employers revise risk assessments and workplace monitoring for cosmic radiation exposure?
- Do national screening protocols for breast and other radiation‑associated cancers need adjustment for long‑serving aircrew?
- Are current crew rostering and maximum flight‑hour rules adequate to limit cumulative dose?
| Metric | Reported figure |
|---|---|
| Decedents analysed | 12.7 million |
| Pilots in dataset | ~14,000 |
| Flight attendants in dataset | 7,000+ |
| Share of radiation-related cancer deaths — flight attendants | 6.9% |
| Share of radiation-related cancer deaths — pilots | 6.7% |
While the study does not establish precise causal mechanisms at the cellular level, its authors argue the occupational exposure profile of aircrew — long-term cumulative exposure to cosmic ionising radiation — is a plausible explanatory factor. The lack of an elevated risk among ground‑based aircraft workers strengthens the association with time spent at altitude rather than proximity to aircraft.
Limitations and next steps
The analysis is based on death-certificate data, which can be limited by the accuracy of cause-of-death coding and does not capture individual flight histories, shielding, or lifestyle factors that may confound associations. The investigators used statistical adjustment and control occupations to mitigate some biases, but further research with individual exposure assessment would give greater clarity.
For policymakers and airline occupational-health services in South Africa and globally, the study signals a need to consider whether existing occupational-dose monitoring, crew rostering and cancer-screening recommendations adequately protect long-serving aircrew. Radiologists and screening programme managers may also need to examine whether tailored guidance is required for this workforce.
The study adds to an emerging body of evidence that occupational exposure in aviation warrants closer attention from regulators, employers and clinicians tasked with protecting the health of those who work in the skies.
