A new study published in Occupational and Environmental Medicine by researchers at the Danish Cancer Society seems to show that working the night shift raises a woman's risk of developing breast cancer, reports The Guardian's James Meikle. Night shift work was associated with a 40 percent increased risk, he adds. Though the risk is not firmly established, the UK's Health and Safety Executive has commissioned research on the effect of night shift work on chronic disease — specifically, it has asked cancer epidemiology researchers at Oxford University to investigate disruptions to people's body clocks and the relationship to disease.
"In the latest study, from the Danish Cancer Society's institute of epidemiology, those who had worked nights at least three times a week for at least six years were more than twice as likely to have [breast cancer] as those who had not," Meikle says. "But there was 'a neutral link' for those who worked only one or two night shifts per week." Some have argued that night shift work contributes to the formation of cancer because it suppresses the production of melatonin and other metabolic and physiological processes, he adds.