A new study published in JAMA Internal Medicine has brought renewed attention to a question that has concerned the aviation community for decades: does a career spent at altitude come with long-term health consequences?

The study, published in August 2026, looked at cancer-related mortality among US pilots and flight attendants. Its findings are striking. Among 503 occupations, flight attendants had the highest risk-adjusted proportion of deaths from cancers associated with radiation, with pilots ranking second.

Combined with what we already know about cosmic radiation, emerging evidence on UV-A exposure in cockpits and continuing questions surrounding cabin air quality, it adds another important piece to the discussion about the occupational health of professional aircrew.

Researchers from Harvard Medical School and associated institutions analysed 12,710,517 deaths in the United States between 2020 and 2024, divided across 503 occupations. The dataset included 14,190 pilots and 7,170 flight attendants.

Rather than looking at the overall number of cancer deaths alone, the researchers separated cancers into two groups: cancers previously associated with radiation exposure and other cancers.

The radiation-related category included:

The result was remarkable. Of all 503 occupations, flight attendants ranked first, with an adjusted 6.9% of deaths attributable to these radiation-related cancers. Pilots ranked second at 6.7%. For cancers not classified as radiation-related, aircrew were much closer to the middle of the occupational distribution.

The researchers also included two particularly interesting control groups. Aircraft mechanics and aircraft assemblers were used as negative controls: they work around aircraft but are not routinely exposed to cosmic radiation at cruising altitude. Neither group showed the same elevated mortality pattern. As a positive control, the researchers selected nuclear technologists, a profession with recognised occupational radiation exposure. They ranked only 12th for radiation-related cancer mortality.

Association is not causation

The JAMA study does not demonstrate that cosmic radiation caused these cancers. The researchers did not have individual lifetime radiation measurements for the people included in the dataset. The study was based on death certificates and usual occupation, rather than following individual pilots throughout their careers while recording their actual exposure. Other possible contributing factors such as circadian disruption and even possible exposure to engine bleed air were not taken into account. Nevertheless, the signal is difficult to ignore.

What exactly is cosmic radiation?

Cosmic radiation is high-energy ionising radiation originating from space and, to a lesser extent, energetic particles associated with the Sun. At ground level, Earth’s atmosphere and magnetic field provide substantial protection. At airline cruising altitudes, there is much less atmosphere above the aircraft to absorb this radiation. How much radiation a crew member receives depends mainly on altitude, latitude, time spent flying and solar activity. Radiation levels generally increase with altitude and are higher towards the polar regions because Earth’s magnetic field provides less shielding there.

This means that two pilots flying the same number of hours can accumulate different doses depending on the routes they operate.

Between 3 and 6 mSv per year in the US

The JAMA researchers estimate that US pilots and flight attendants accumulate approximately 3 to 6 millisieverts (mSv) of cosmic radiation per year. For comparison, they cite approximately 0.4 mSv for a passenger making ten cross-country round trips per year. For 2024, the Belgian Federal Agency for Nuclear Control (FANC) received dose data for 4,163 crew members employed by Belgian airlines. Of these, 2,577 exceeded 1 mSv during the year. The average recorded exposure was 1.22 mSv, while the highest individual value was 4.87 mSv. BeCA already discussed this subject directly with FANC in 2025. Although annual doses are relatively low, the issue becomes more relevant when exposure is accumulated over an entire professional career. 

Solar storms: when space weather reaches the cockpit

Cosmic radiation is not completely constant. Solar activity can significantly alter the radiation environment at aviation altitudes. During certain solar radiation events, energetic particles from the Sun can reach Earth’s atmosphere and temporarily increase radiation exposure, particularly at high altitude and high latitude.

Another type of radiation: In October 2025, the European Cockpit Association published its position paper Protecting Pilots Against UV-A Radiation.

UV-A exposure increases with altitude by approximately 10–15% for every 1,000 metres, while reflection from clouds, snow and water can further increase exposure. The aircraft itself should provide protection — but not every cockpit window provides the same protection. ECA notes that while cockpit windows generally block UV-B, UV-A transmission varies between aircraft types and can even vary between different windows on the same aircraft. Manufacturers often do not publicly provide the relevant specifications.

Recent measurements illustrate just how that not every cockpit window is equal. A study involving 39 flights in 15 Airbus A320/A321 aircraft measured UV-A transmission through each of the six cockpit windows. All front windshields provided effective UV-A protection. Several side and rear windows did not. Data presented at the 2025 European Society of Cataract and Refractive Surgeons congress found substantial differences between aircraft types and cockpit windows. In the aircraft tested, windshields on the Airbus A380 and A350 and Boeing 747 and 787 provided full protection, whereas incomplete UV-A blocking was found in some tested windows on the A320, A330 and A340, and in the tested Boeing 777 windows. 

These results should be interpreted cautiously: they do not mean that every A350 or 747 in service necessarily has identical UV characteristics, nor that every A320 or 777 window is problematic. Window construction, position and potentially individual windshield characteristics matter.

ECA therefore calls for the UV-blocking properties of cockpit windows to become part of aircraft certification requirements and recommends actual measurements where manufacturer specifications are unavailable.

Why does UV-A matter?

UV exposure has long been associated with skin and eye damage. ECA points to epidemiological research showing increased incidence and mortality from keratosis, basal-cell carcinoma and melanoma among pilots, while simultaneously acknowledging that the precise contribution of occupational cockpit UV-A exposure to melanoma remains unclear.

What the two studies do show together is that radiation exposure deserves to be taken seriously as an occupational-health issue for aircrew.

ECA recommends long-sleeved clothing, high-SPF sunscreen on exposed skin and sunglasses blocking 99–100% of UVA and UVB. Where the UV protection provided by cockpit windows is inadequate or uncertain, installed sunshades should be used.

Radiation is not the only long-term exposure

There is an even broader question behind all of this. Pilots and cabin crew do not spend their careers exposed to one isolated occupational factor.

Earlier this year, BeCA attended the Cabin Air Quality Conference in Lisbon, where increasing attention was given to repeated low-level exposure to contaminants over an aviation career. The parallel with the radiation discussion is striking.

Cabin air contamination, cosmic radiation and cockpit UV-A are three very different subjects. They should not be scientifically bundled together and there is currently no evidence demonstrating that their effects simply add up to one combined health risk. But they have something important in common: exposure can be occupational, repeated and cumulative over decades, while some potential health consequences may only become visible many years later.

That should matter when we discuss how long a professional pilot’s career should last. This discussion comes at a particularly relevant moment in Belgium.

Since January 2025, Belgium’s statutory retirement age has been 66, and it is scheduled to increase to 67 in 2030. Yet European rules currently prevent commercial airline pilots from operating in multi-pilot commercial air transport after the age of 65. In May 2026, an N-VA parliamentary resolution proposed initiating a European “Green Card” procedure asking for the limit to be reconsidered. BeCA has already expressed serious reservations about this approach. The new JAMA study adds another element that policymakers should not ignore. Extending a pilot’s career means extending occupational exposure.

As Belgium debates whether pilots should eventually be expected to continue their careers beyond 65, policymakers should look beyond pension spreadsheets and licence rules.