These include breast, uterine, gastrointestinal, thyroid and cervical cancer. Flight attendants had a 51% higher prevalence of breast cancers, more than two-fold higher prevalence of melanoma and four-fold greater prevalence of non melanoma skin cancers, compared to people not in the profession. The study also revealed for the first time a higher rate of non-melanoma skin cancers, such as basal cell and squamous cell carcinomas, among flight attendants.
Corresponding author Dr Irina Mordukhovich said: "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". Even when flight attendants reported having stereotypically good health, diet, and exercise regimens, the likelihood that they would be stricken with certain cancers was still higher than the other survey respondents.
Flight crews are routinely exposed to known and probable carcinogens, including cosmic radiation from space, circadian rhythm disruption and possible chemical contaminants.
"Neither OSHA nor the FAA require airlines to educate flight attendants about onboard radiation exposure or offer protections during pregnancy, cabin air can be contaminated, and cabin crew fatigue is prevalent", Nelson, president of the Association of Flight Attendants-CWA, said in a statement. "This is striking given the low rates of overweight and smoking in this occupational group".
Cancer rates in male flight attendants were almost 50 percent higher for melanoma and about 10 percent higher for nonmelanoma skin cancers compared with men from the general population group, according to the findings.
Which cancer risks are increased in flight attendants? "Combine that with this disruption from the job, especially for those who fly internationally, this may be an indication that the circadian rhythm disruption is having an impact".
Researchers surveyed 5,366 male and female flight attendants from 2014 to 2015 and compared cancer rates to those recorded in the Centers for Disease Control and Prevention's 2013 to 2014 National Health and Nutrition Examination Survey.More news: Can herpes virus cause Alzheimer's disease?
Researchers also couldn't say whether tumors developed before or after participants started working as flight attendants.
Sun exposure, a leading risk factor for skin cancers, might also be higher for flight attendants because they might spend time in the sun on layovers, noted Dr. Alessandra Buja, of the University of Padova in Italy, in an email.
British experts have estimated airline crews receive a higher dose of radiation over a year than workers in the nuclear industry.
Previous research by scientists in Iceland suggested stewardesses were up to five times more likely to contract breast cancer.
"The specific pattern we are seeing is firstly lung injury - the lung's breathing mechanism is fine, but there are problems getting the oxygen out of the air", said Dr Heutelbeck, adding that there are also a common pattern of symptoms related with neurotoxicity and small fibre nerve damage.
Flight attendants had higher rates of all cancers investigated.