Night Shift Work Linked To Higher Ovarian Cancer Risk

Working at night can do more than just ruin your schedule. A recent study has linked night-shift work with a higher ovarian cancer risk.

The study, published in Occupational and Environmental Medicine, followed more than 1,100 women with ovarian cancer and more than 1,800 women without ovarian cancer. Participants were 35 to 74 years old and worked between 2.7 and 3.5 years in fields including health care, food preparation and service, and office and admin support.

According to the study, women who worked night shifts had a 24 percent increased risk of developing advanced cancer and 49 percent increased risk for early-stage cancer.

Only women 50 years and older were significantly more likely to develop ovarian cancer if they had a history of working night shifts, said study author Parveen Bhatti.

Among the participants who worked night shifts, 20 percent considered themselves morning larks and 27 percent said they were night owls. Researchers found that the risk of advanced ovarian cancer was higher among “larks” than among “owls”, the same goes for the risk of borderline disease.

However, the study only found an association between night-shift work and increased risk of ovarian cancer; it did not establish a cause-and-effect relationship.

The researchers suggested that the increased risk for ovarian cancer among women working at night could be associated with melatonin, a regulatory hormone which affects estrogen production. Melatonin is normally produced at night and is limited by light.

Previous studies have suggested a link between night-shift work and increased risk of breast cancer.