Permanent hair dye and chemical hair straighteners could increase the risk of breast cancer risk, especially among Black women, according to an online report published this month by the International Journal of Cancer.
Research from The Sister Study released by the National Institute of Environmental Health Sciences also shows that women who use chemical hair straighteners every five to eight weeks were about 31 percent more likely to develop breast cancer than those who don’t. While the connection between straightening hair and breast cancer were similar among Black and White women, Black women, the study found, are more likely to straighten their hair, which puts them at a higher risk.
“These findings are significant,” said NIEHS researcher Dale Sandler and one of the study’s authors said in a statement. “The relative risk of developing breast cancer if you are a Black woman who uses hair dye is relatively large compared to that of nonusers.” However, Sandler added that the absolute number of new cases of breast cancer due to hair dye remains small.
Also, while chemical treatments used to permanently or semi-permanently straighten or relax hair contain a mixture of chemicals, many straighteners contain formaldehyde, which is considered a cancer-causing agent.
Listed among researchers’ findings after eight years of follow-up:
• Overall, women who regularly used permanent hair dye in the 12 months before joining the study were 9 percent more likely to develop breast cancer than women who didn’t use hair dye.
• Black women who used permanent hair dye every 5 to 8 weeks or more in the 12 months before joining the study were 60 percent more likely to develop breast cancer than women who didn’t use hair dye.