SAN FRANCISCO, June 25 (Xinhua) -- U.S. flight attendants are having a higher rate of developing various cancers than the general population, a study showed Monday.

The study, which was conducted by researchers at Harvard T. H. Chan School of Public Health in Boston, Massachusetts, surveyed 5,366 U.S. flight crew members and found that slightly over 15 percent of them reported having been diagnosed with cancer.

The results of the study were published in the journal Environmental Health Monday.

Irina Mordukhovich, corresponding author of the study, said the research is one of "the largest and most comprehensive studies of cancer among cabin crew to date."

The researchers revealed flight crew are more likely to develop many cancers than the general population, including breast, uterine, cervical, gastrointestinal and thyroid cancers.

There is a higher risk of breast cancer in women never had children and women who had three or more children, according to the study.

"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," said Mordukhovich.

She said circadian rhythm disruption, or sleep deprivation and irregular schedules, both at home and work may contribute to the higher risks of breast cancer.

As for male flight attendants, they are more likely to have melanoma and non-melanoma skin cancers, especially if they were exposed to high levels of secondhand smoke.

The researchers studied the data from a survey conducted from 2013 to 2014 as part of the Flight Attendant Health Study, which was first launched in 2007.

The study says more than 80 percent of the flight attendants whose data were analyzed were female, who were 51.5 years old on average and had worked in the profession for over two decades.