A study has found that the use of at-home permanent hair dyes is not linked to most cancers. The study looked at data from 117,200 female nurses, including their exposure to hair dye. The women were followed for 36 years and did not have cancer before the study began. The use of hair dye did not increase the risk of bladder, brain, colon, kidney, lung, or blood cancer. It also did not increase the risk of most types of breast or skin cancers. However, the use of hair dye was linked to an increased risk of ovarian cancer and 3 types of breast cancer. The researchers also found an increased risk of Hodgkin lymphoma in women who used hair dye that had naturally dark hair. A professor of cancer at the University of Cambridge says the links between cancer and hair dye ?are very weak?. The reported associations are very weak and given the number of associations reported in this manuscript they are very likely to be chance findings, Paul Pharoah, Professor of cancer epidemiology at the University of Cambridge. It is estimated that 50-80% of women and 10% of men over the age of 40 in the US and Europe use hair dye