Findings support efforts to protect US aircrews from cosmic radiation exposure
Of more than 500 occupations in the United States, flight attendants and pilots have the highest and second-highest proportion of radiation-related cancer deaths, a new study has found.
The results support considering occupational radiation protections for U.S. aircrew members commensurate with their level of exposure, said senior author Anupam Jena, the Joseph P. Newhouse Professor of Health Care Policy in the Blavatnik Institute at Harvard Medical School, and team.
It’s been known that aircrew members receive the largest annual effective dose of ionising radiation of any workforce in the United States, largely due to exposure to cosmic radiation at high altitudes. Members of the profession are also more likely to be diagnosed with certain cancers than the general population. But studies have been limited as to whether this translates to higher rates of cancer mortality.
The new research, published August 17 in JAMA Internal Medicine, studied this question using a larger dataset and more statistical power than were previously available.
The study, led by first author Vishal Patel, HMS clinical fellow in surgery at Brigham and Women’s Hospital, used a single population-based data source – the National Vital Statistics System – rather than individual occupational or cancer cohorts. Patel and colleagues looked at all U.S. death certificates from 2020 to 2024. These records have only recently been linked to the occupation of the decedent. The records yielded data from nearly 13 million decedents across 503 occupations, including 14000 pilots and 7000 flight attendants.
The team applied what’s known as a common adjustment approach, which accounted for several factors other than occupation that may affect mortality. These included age at death, sex, race, ethnicity, educational attainment, and marital status.
The researchers analysed radiation- and non-radiation-related cancers across occupations. They also compared flight crew members to ground-based aviation workers.
Radiation-related cancers analysed here included breast cancer, central nervous system cancers, multiple myeloma, leukaemia (except chronic lymphocytic leukaemia), lymphoma, thyroid cancer, prostate cancer, melanoma, and non-melanoma skin cancers. (The team excluded lung cancer to reduce potential confounding with smoking.)
The team found that pilots and flight attendants had statistically significantly higher rates of death from breast, central nervous system, and prostate cancers and melanoma. Pilots also had a higher rate of leukaemia deaths.
In all, about 6.9% of deaths among flight attendants and 6.7% of deaths among pilots were from radiation-related cancers, according to the analysis. These proportions were higher than for any of the other professions, including nuclear technologists, who are routinely exposed to radiation from non-cosmic sources yet placed 12th on the list, the authors said. Aircraft mechanics and assemblers did not have higher rates than other occupations.
Rates of non-radiation-related cancer deaths among aircrew members were similar to the general U.S. population.
Aircrew accrue an estimated 3 to 6 millisieverts per year of cosmic radiation (depending on flight paths), 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, according to the CDC.
The Federal Aviation Administration formally recognises pilots and flight attendants as occupationally exposed to ionizing radiation, but unlike other radiation-exposed workers or aircrew in other countries, U.S. aircrew are not subject to federal dose limits or monitoring requirements.
Original written by Katie Brace
Source: Harvard Medical School
