Women who use permanent hair dye and chemical hair straighteners have a higher risk of developing breast cancer than women who don't, according to research from the National Institutes of Health.
The study of 46,709 women found that women who regularly used permanent hair dye in the year prior to enrolling in the study were 9% more likely than women who didn't use hair dye to develop breast cancer (International Journal of Cancer, December 3, 2019).
Among black women, using permanent dyes every five to eight weeks or more frequently their increased risk by 60% compared with an 8% increased risk for white women. The research team found little to no increase in breast cancer risk for semipermanent or temporary dye use.
In addition, the study team led by Alexandra White, PhD, head of the National Institute of Environmental Health Sciences (NIEHS), found a link between chemical straighteners and breast cancer.
Women who used hair straighteners at least every five to eight weeks were about 30% more likely to develop breast cancer. The risks for black women and white women was similar, but straightener use was much more common among black women.
Although there is some prior evidence to support the association with chemical straighteners, these results need to be replicated in other studies, noted study co-author Dale Sandler, PhD, chief of the NIEHS Epidemiology Branch.