Flight Crews Face Higher Cancer Risk from Cosmic Radiation, Study Finds

New research has found that pilots and flight attendants are more likely to develop certain types of cancer than people in other professions. The study, published in the Journal of the American Medical Association (JAMA) on Monday, points to prolonged exposure to cosmic radiation at high altitudes as the likely cause.

While passengers who fly occasionally face negligible health risks, airline crews spend hundreds of hours each year in the atmosphere, where Earth's protective air barrier is significantly thinner. This means crew members absorb higher lifetime doses of ionising radiation.

"Aircrew members receive the largest mean annual effective dose of ionising radiation of any occupational group in the US, primarily due to cosmic rays encountered at commercial flight altitudes," the researchers wrote. They added that the potential health consequences, including cancer risk, have become a priority for public health experts and federal agencies.

The study was carried out between 2020 and 2024 to examine the risks of "radiation-related cancer mortality" among pilots and flight attendants compared with other occupations. Records from around 14,000 pilots and 7,000 flight attendants were used, according to Harvard Medical School, which collaborated on the research.

The team screened for breast cancer, central nervous system cancers, multiple myeloma, leukaemia, and other cancers. They compared pilots and flight attendants with non-flying workers while considering factors such as age, race, education, and marital status. After studying more than 500 occupations, they found that aircrew members are at greater risk.

Why does this happen? At ground level, Earth's thick atmosphere shields living organisms from space-borne radiation. However, high-altitude flight routes reduce that natural barrier, exposing planes to higher background radiation levels. Long-haul international flights and polar routes expose crews to even higher radiation due to the weaker magnetic field near the poles.

The US Centers for Disease Control and Prevention (CDC) notes that ionising radiation is a powerful form of energy that can alter the body's cells and DNA if absorbed at high levels. Harvard Medical School cited CDC data showing that aircrew accrue an estimated 3 to 6 millisieverts per year of cosmic radiation, depending on flight paths. This is an order of magnitude above the estimated 0.4 millisieverts received annually by an average air traveller taking 10 cross-country round-trip flights per year.

The researchers emphasise that aviation workers need clearer safety guidelines, regular medical screenings, and better monitoring of overall flight hours to help reduce health risks. They call on airlines and regulators to prioritise the well-being of crew members who spend their working lives in the skies.