Cabin crew at higher risk of radiation-related cancer than nuclear technologists

Study Ranks Flight Attendants and Pilots Above Nuclear Technologists

The research, led by surgeon and health researcher Vishal Patel from Harvard Medical School, analyzed data from the US National Vital Statistics System. Scientists examined death certificates for 12.7 million people who died between 2020 and 2024 across 503 occupations, a dataset that included 14,000 pilots and 7,000 flight attendants.

The analysis accounted for factors such as age at death, sex, race, ethnicity, educational attainment, and marital status. Researchers found that flight attendants had the highest percentage of deaths from radiation-related cancers, placing them first, while pilots ranked second.

High Altitudes and Cumulative Cosmic Radiation Exposure

The elevated risk is primarily driven by exposure to cosmic radiation at commercial flight altitudes, according to the research. While Earth’s atmosphere protects people at ground level by forcing space particles to collide with air atoms and lose energy, commercial airliners climb above a substantial portion of that protective blanket.

Pilots and flight attendants accrue an estimated 3 to 6 millisieverts of cosmic radiation each year. By comparison, an average air traveler taking 10 cross-country round-trip flights in the US receives roughly 0.4 millisieverts annually, while living at sea level involves much lower baseline exposure.

Geographic factors also influence the dose. Cosmic particles are deflected by Earth’s magnetic field, offering greater protection near the equator and weaker protection toward the magnetic poles, meaning long flights at high northern latitudes produce greater radiation doses.

Examining Cancer Types and Dispelling Layover Theories

The study focused on cancers previously suggested to be associated with radiation, including breast cancer, leukemia, lymphoma, multiple myeloma, central nervous system and brain tumors, thyroid cancer, prostate cancer, and melanoma and keratinocyte skin cancers.

Researchers found that about 6.9 percent of deaths among flight attendants and 6.7 percent among pilots were from these radiation-related conditions, representing roughly 1 in 14 deaths. In terms of relative risk, flight attendants had about 50 percent higher odds of dying from a radiation-related cancer than the general working population, while pilots had about 36 percent higher odds.

Commentary writers Olsen, from the University of Queensland in Australia, and Ken Karipidis, from the Australian Radiation Protection and Nuclear Safety Agency, noted that neither group showed higher-than-normal death rates from cancers not tied to radiation. Furthermore, aircraft mechanics and engineers who spend their careers around airplanes on the ground did not exhibit the pattern.

The findings help challenge the notion that flight crews’ excess skin-cancer risk stems from long, sun-drenched stopovers. According to Olsen and Karipidis, tighter scheduling, reduced layover times, and back-to-back flight sectors have largely eliminated extended vacation stopovers, suggesting that the cockpit itself is the primary exposure environment.

Study Limitations and Recommendations

While the data confirms an association between cumulative in-flight cosmic radiation and a range of radiation-related cancers, researchers noted limitations. The study does not definitively prove that cosmic rays directly caused the recorded cancers, as death certificates did not track how many years individuals spent flying, their specific flight routes and altitudes, or their exact accumulated radiation doses.

Additionally, researchers pointed out that cancer risks can be compounded by overlapping exposures, including UV-A light and circadian disruption caused by jet lag, crossing time zones, and irregular work schedules.

Harvard Medical School researchers have called for occupational radiation protections for aircrew members that align with their actual exposure levels.