Working the night shift might raise a man's risk of prostate cancer by nearly three times, according to a new study in the American Journal of Epidemiology.
Researchers at the University of Quebec and the Centre INRS-Institut Armand-Frappier looked at whether working the night shift raised the risk of different cancers in men. Their analysis was based on 3,137 men who had had cancer at one of 11 different sites on their bodies, as well as 512 controls who didn't have cancer.
Researchers found specifically that working the night shift is linked with a 2.77 times higher risk of prostate cancer, as well as a 1.76 times higher risk of lung cancer, a 2.03 times higher risk of colon cancer, a 1.74 times higher risk of bladder cancer, a 1.31 times higher risk for non-Hodgkin's lymphoma, a 20.9 times higher risk for rectal cancer and a 2.27 times higher risk for pancreatic cancer.
While it's not exactly clear how night shift might affect cancer risk, "exposure to light at night can lead to a reduced production of the sleep hormone melatonin, inducing physiological changes that may provoke the development of tumors," study researcher Marie-Élise Parent, of the Centre INRS-Institut Armand-Frappier, said in a statement. "This hormone, habitually released in the middle of the night in response to absence of light, plays a pivotal role in hormonal functions and in the immune system."
Working the night shift has been linked with a myriad of other health conditions; click through the slideshow for more.