New research raises concern in the beauty industry when it comes to permanent hair dye and chemical hair straighteners, especially among African American women. The study published this week in the International Journal of Cancer says there may be a link between those hair chemicals and breast cancer.
Previous research in animals has found links between certain chemicals in hair dye and straighteners and cancer. But findings from other human studies on the association between hair dyes and straighteners and cancer have been inconsistent. This large, prospective study provides firmer evidence of a link.
Using data from 46,709 women in the Sister Study, researchers at the National Institute of Environmental Health Sciences (NIEHS), part of NIH, 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.
Among African American women, using permanent dyes every five to eight weeks or more was associated with a 60% increased risk of breast cancer as compared with an 8% increased risk for white women.
That risk was even higher among black women who dyed their hair frequently, every one or two months.
“The association was notably higher among black women,” says epidemiologist Alexandra White, study author and an investigator with the National Institute of Environmental Health Sciences, who studies environmental risk factors for breast cancer.
Researchers don’t know which ingredients in the products might be of concern. The study did not look at the specific ingredients in the products women were using, only at whether they had used the product and whether they developed breast cancer.
All women in the Sister Study were already at high risk for breast cancer since they had a sister who had breast cancer.
Researchers note that in the United States, breast cancer incidence remains high for