Cabin crew are much more likely to develop cancer, according to new research.
A study of more than 5,000 flight attendants found cases were higher for every form of the disease examined.
The risk of breast cancer, for instance, was around 50 per cent more for air stewardesses than other women.
It was one of the most extensive analyses of its kind and scientists described the findings as particularly alarming owing to their healthy lifestyles.
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.
“Consistent with previous studies, we report a higher lifetime prevalence of breast, melanoma and non-melanoma skin cancers among flight crew relative to the general population.
“This is striking given the low rates of overweight and smoking in this occupational group.”
Cancer Research UK has warned people working in these occupations should be fully aware of the potential risks.
The study, published in the journal Environmental Health, suggested some but not all of the increased incidence was linked to the time spent in the job – meaning doing it for less than five years raises the risk.
Dr Mordukhovich, of Harvard T. H. Chan School of Public Health in the United States, and colleagues found out of the 5,366 US flight attendants surveyed one-in-seven had been diagnosed with cancer.
After taking age into account there was higher prevalence of every cancer looked at compared to the general public. Over 80 percent of the participants were female.
These included those of the breast (3.4% against 2.3%), womb (0.15% against 0.13%), cervix (1% compared to 0.7%), gastrointestines (0.47% compared to 0.27%) and thyroid (0.67% compared to 0.56%).
The researchers also found an association between each five-year increase in time spent working as a flight attendant and non-melanoma skin cancer among women.
But no link was identified between job tenure and thyroid cancer or melanoma – the deadliest skin cancer – in women.
And it was only associated with higher risk of breast cancer in women who either had never had children – nulliparity – or had three or more.
Dr Mordukhovich said: “Nulliparity is a known risk factor for breast cancer but we were surprised to replicate a recent finding that exposure to work as a flight attendant was related to breast cancer exclusively among women with three or more children.
“This may due to combined sources of circadian rhythm disruption – that is sleep deprivation and irregular schedules – both at home and work.”
Male flight attendants were found to have higher rates of melanoma and non-melanoma skin cancer (1.2% and 3.2% compared to 0.69% and 2.9% in the general population, respectively).
This was especially the case if they were exposed to high levels of occupational secondhand smoke before the introduction of smoking bans in 1998.
Dr Mordukhovich said: “Our study informs future research priorities regarding the health of this understudied group of workers, who have a wide range of job-related exposures to known and probable carcinogens including cosmic ionizing radiation, circadian rhythm disruption and possible chemical contaminants in the aircraft cabin.
“Our findings raise the question of what can be done to minimize the adverse exposures and cancers common among cabin crew.”
Her team used data from a survey carried out from 2013 to 2014 as part of the ongoing Flight Attendant Health Study established in 2007. Participants had an average age of 51 and had been in the profession for just over 20 years.
They compared the self-reported cancer diagnoses with figures on a matching cohort of 2,729 men and women with similar economic status collected as part of the National Health and Nutrition Examination survey during the same years.
At high altitudes, where the air is thinner and provides less of a shield, passengers and crew can be exposed to between 100 and 300 times the cosmic radiation dose they receive at sea level.
British experts have estimated airline crews receive a higher dose of radiation over a year than workers in the nuclear industry.
Long-haul trips which disrupt the body clock and affect hormone levels are additional risks.
Previous research by scientists in Iceland suggested stewardesses were up to five times more likely to contract breast cancer.
This is because they fly more northerly routes where exposure to cosmic radiation is highest. And the risk of melanoma rose three times for cabin crew of both sexes.
The average amount of exposure to radiation has increased over time as planes fly higher and for longer.
Earlier this month we reported how campaigners concerned by leaks of toxic fumes into cabin air on flights on passenger planes that have bleed air systems recycling air that has passed over the engine are calling for an international inquiry into how this affects the health of passengers and crew.
And at the end of last year, the London Economic also spoke to Dr Astrid Heutelbeck who has spent the past few years attending to patients suffering pulmonary, neurological and cerebral symptoms after flights with suspected cabin air contamination at the University of Gottingen, Germany. Dr Heutelbeck revealed she has treated around 500 patients in three and a half years.
“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. Some of her patients have been exposed to fume events, other exhibit similar symptoms from repeated exposure to cabin air.
Dr Heutelbeck has also been treating passengers who are frequent flyers as well.
Other studies have found higher rates of deaths from cancer among cabin crew and higher rates of specific diseases such as chronic bronchitis and cardiac disease in flight attendants than the general population. This despite cabin crew being generally less overweight and less likely to smoke than non-crew.
By Ben Gelblum and Mark Waghorn