Women who have worked decades on the night shift face more than double the risk of breast cancer, this Canadian study found. In the study of 1,134 cases and 1,179 controls, breast cancer odds ratios of 2.21 were found in those who had worked 30 or more years on nights. Nurses, cleaners, care workers, some shop workers, call centre workers and others who work night shifts for long periods can have double the risk of developing the disease than those who don’t, the new study indicates. The report concludes: “Long-term night shift work in a diverse mix of occupations is associated with increased breast cancer risk and not limited to nurses, as in most previous studies.”

Anne Grundy, Harriet Richardson, Igor Burstyn and others. Increased risk of breast cancer associated with longterm shift work in Canada, Occupational & Environmental Medicine, volume 70.2, pages 831-838, July 2013. Medical Daily. Huffington Post. Risks 612.