Flight attendants have a tough job. On top of the psychological strain from having to deal with some truly ill-behaved customers, crew members face numerous physiological hazards in the form of frequent circadian rhythm disruptions, breathing poor-quality recycled air, and exposure to ionizing radiation from spending so much time in the upper atmosphere.
Medical scientists have known about the potential health risks of this career field for some time, yet the results from the small handful of studies focused on the issue have been frustratingly contradictory, especially when it comes to cancer.
But now, a new investigation by the Harvard T. H. Chan School of Public Health appears to quash past uncertainty after finding that a sizable group of airline crew members had higher-than-normal rates of many cancer types.
“We report a higher prevalence of every cancer outcome we examined among cabin crew relative to the general population,” the team wrote in the journal Environmental Health, “including breast, uterine, cervical, gastrointestinal, thyroid, melanoma, and non-melanoma skin cancers.”
Their ongoing research project, called the Harvard Flight Attendant Health Study (FAHS), began collecting self-reported medical data from 5,366 flight attendants in 2007. The current study used information from the 2014 to 2015 survey and compared it to health outcomes from 2,729 control subjects who were matched for socioeconomic status.
Among women crew members, the rates of breast (3.4 percent of flight crew vs 2.3 percent in the general population), uterine (0.15 vs 0.13), cervical (1.0 vs 0.70), gastrointestinal (0.47 vs 0.27), and thyroid (0.67 vs 0.56) cancers were only slightly elevated compared with controls, yet statistical analyses indicated that this pattern was very unlikely due to random chance.
For male flight attendants, the authors found higher rates of melanoma (1.2 percent of flight crew compared with 0.69 percent in the general population) and non-melanoma skin cancer (3.2 vs 2.9 percent).
Additionally, each five-year chunk spent in the industry was linked to a modestly greater risk of non-melanoma skin cancers in women and all skin cancers in men.
"Our study is among the largest and most comprehensive studies of cancer among cabin crew to date and we profiled a wide range of cancers,” author Dr Irina Mordukhovich said in a statement. “This is striking given the low rates of overweight and smoking in this occupational group."
Of course, this study is only able to report correlation, not causation, and the authors concede that there were non-trivial differences in the demographics of the FAHS and control groups that could have skewed the results. For example, the flight staff participants tended to be older than control subjects and a larger proportion were women.
An investigation using control subjects that are also matched for age and sex and data gathered from actual medical records rather than self-reports will yield more solid associations.