Flying High: The Genotoxic Effects of Flying on Airplane Crew and Pilots

Sara Leora Wiener

From the TV show “Pan-Am” to the growing trend to travel the globe, there are many opportunities for us to explore the life of airline pilots and crew. While this life may seem full of exotic trips and locations, the realities are harsher than sunshine and hotels. Prolonged time spent flying results in higher risks for malignant melanoma and breast cancer. The intense UV and cosmic radiation from the sun causes DNA damage and an increased risk of cancer amongst airline attendants and pilots. Additional health risks incurred from daily flights include DNA damage from increased tobacco consumption as well as lower levels of melatonin, which result in increased cell growth and possible breast cancer growth. Because of these inherent health risks, it is crucial to study the effects of flying on flight crew and increase awareness regarding these effects.

Two different forms of radiation are the primary causes of these high rates of melanoma and breast cancer: UV radiation and cosmic radiation. UV radiation, which is photon energy emitted from sunlight, is barely blocked by the glass in the windows and windshields of planes. Furthermore, at increased altitudes, UV radiation increases as well because of the stronger sun rays penetrating the atmosphere. This radiation causes an increase in the risk for malignant melanoma as well as other cancers, because of its ability to damage the DNA structure. The UV radiation primarily causes thymine dimers, which are kinks in the DNA structure caused by the binding of two thymine bases on the same strand of DNA to each other. These thymine structures cause a kink in the structure of the DNA, contributing to mutations in the DNA code due to miscoding during the transcription and duplication of DNA strands. Depending on the specific genes in which they occur, these mutations can affect proteins that are responsible for cell growth and thereby cause cancer. On the other hand, cosmic radiation is composed of ionized particles that emerge from sunlight energy and hit the earth’s atmosphere. Neutrons make up nearly 60% of these ionized particles. These neutrons are high-energy, which allows them to penetrate our bodies and disrupt the DNA structure. There are various mechanisms by which this form of radiation can affect the structure and function of the DNA, such as causing deletions, breakages and missense mutations in the DNA code. Cosmic radiation has also been proven to damage certain DNA repair mechanisms, which can lead to uncontrollable cell proliferation and eventually cancer.

UV radiation is a primary source of DNA damage studied amongst malignant melanoma cancers. A study of airplane pilots found that the incidence rates of melanoma amongst pilots were twice the rates of the general population. A study of Finnish female flight attendants revealed that the breast cancer incidence rate is 81.2/100,000. In comparison, the breast cancer rate for the general Finnish female population is approximately 57.4/100,000. This increase in breast cancer cases has been attributed to the cosmic radiation that flight attendants are exposed to during flights. An additional factor that may contribute to the breast cancer is a decrease in melatonin production amongst flight crew because of the disruption in their circadian rhythm. Melatonin is a hormone that slows cell growth and interacts with estrogen in breast cells that have the potential to become cancerous. Reduced melatonin levels cause an increase in cell growth, primarily in cells that are sensitive to estrogen, which has been proven to increase breast cancer cell growth.  Therefore, the cosmic radiation exposure, which is proven to have genotoxic effects, along with decreased levels of melatonin, form a perfect combination for breast cancer in flight attendants.

Though it may be tempting to leave college and travel the world as a flight attendant or pilot, one should carefully consider that sleep deprivation from finals is no match for the genotoxic effects of cosmic and UV radiation.