Men who work night shifts are three times more likely to develop prostate cancer than those who work day shifts, according to a Canadian study examining the adverse effects of night work on men’s health. Night shifts also increase the risk of a number of other types of cancer – of the intestine, bladder and lungs, the team from the University of Quebec specifies. It is believed that the negative effect is due to suppression of the hormone melatonin, which promotes the growth of tumors. Deprivation of adequate sleep has been found to be another risk factor. Previous studies have also shown a link between cancer and night work, but most have focused on the higher incidence of breast cancer in women. However, with the latter, it is clear that men are also affected. According to scientists, night shifts harm the body because they suppress the activity of melatonin, which is produced by the pineal gland in the brain. The hormone dictates sleep cycles. Melatonin production is normal during the night hours. But experts believe that exposure to light at night disrupts the production of the hormone, setting off a chain of events in the body that can promote tumor development. NEWS_MORE_BOX The new study included 3,137 men diagnosed with different types of cancer. The researchers calculated how much of the participants worked at night and compared the results to the work patterns of more than 500 healthy men. Night shifts were found to almost triple the risk of prostate cancer and double that of colon cancer. Night workers are 76% more likely to develop lung cancer and 70% more likely to develop bladder cancer. The risk of prostate, colon and bladder cancer is highest when working at night for 10 years. The results are reported in the American Journal of Epidemiology.