BBC News reports that Japanese scientists have found a positive correlation between working rotating shifts and prostate cancer incidence. Men who work a rotating shift were found to be four times more likely to develop prostate cancer than those who only worked day or night shifts. Shift work also was linked to increased rates of breast and bowel cancer. Henry Scowcroft, of Cancer Research UK, said of the report: "There have been several previous reports that disturbances to natural body rhythms might be linked to cancer, and this report adds to that evidence. But it has never been shown that the actual sleep disturbance itself is responsible for the slight increase in risk observed in these studies. It might be that people with abnormal sleep patterns are more likely to be doing something else, such as smoking or eating unhealthily, that increases their risk."