It's not always sunny to fly on an aeroplane.

If you've even sat in the wrong spot, you're more likely to get sick. And for the flight attendants who spend much of their time in the air, there may be some health risks as well.

In a study published Monday in the journal Environmental Health, researchers at Harvard's T.H. Chan School of Public Health found that flight attendants were more likely to have cancer than the general population.

Compared with the general population, here's how the cancer rates compare for female flight attendants:

  • Breast cancer: 3.4 percent in flight crew, 2.3 percent in general population
  • Uterine cancer: 0.15 percent in flight crew, 0.13 percent in general population
  • Cervical cancer: 1.0 percent in flight crew, 0.70 percent in general population
  • Gastrointestinal cancer: 0.47 percent in flight crew, 0.27 percent in general population
  • Thyroid cancer: 0.67 percent in flight crew, 0.56 percent in general population

Women who had no children or had three or more children had a higher risk of breast cancer the longer they stayed on the job.

Here's how the cancer rates compared for male flight attendants:

  • Melanoma skin cancer: 1.2 percent in flight crew, 0.69 percent in general population
  • Nonmelanoma skin cancer: 3.2 percent in flight crew, 2.9 percent in general population

The authors used self-reported data from 5,366 US flight attendants and compared it with data from a matching group of 2,729 men and women with similar economic status who participated in the National Health and Nutrition Examination survey collected during the same years.

The authors suggested the higher cancer rates among flight attendants came down to factors related to their jobs.

Flight attendants are more often exposed to probable carcinogens in the cabin environment including cosmic ionizing radiation at flight altitude.

They may also experience circadian-rhythm disruption caused by irregular work schedules and time-zone shifts. Poor cabin air quality and high levels of second-hand tobacco smoke before in-flight smoking bans were implemented may also contribute to cancer risk.

"In the EU, air crew's radiation exposures are monitored and their schedules are created to minimise their dose, especially while pregnant. Similar policies are not in place in the US," Irina Mordukhovich, one of the authors of the study, told Business Insider.

"Another area of concern is crews' schedules with regard to circadian rhythm adjustment, including mandated rest times between flights."

Mordukhovich said that aside from policy, crew members can take certain precautions such as wearing sunscreen on the aircraft to protect from UV rays, maintaining healthy and consistent sleep practices on their days off, as well as eating a healthy diet and exercising.

This article was originally published by Business Insider.

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