Study: Hair dye, straighteners linked to increased breast cancer risk

Some hair products could put women at an increased risk of developing breast cancer, especially black women, according to a study published by the International Journal of Cancer.

The study was funded by the National Institutes of Health and the National Institute of Environmental Health Sciences.

It followed 46,700 cancer-free women whose sisters had been diagnosed with breast cancer. The women, aged between 35 and 74, answered demographic and lifestyle questions, including about their hair product use for the last 12 months.

After a period of about eight years, 2,794 breast cancer cases were identified. Permanent hair dye use was associated with a 45% higher breast cancer risk in black women and a 7% risk in white women, according to the study. Among all participants, regular use of a chemical relaxer or straightener was also associated with an 18% increased risk.

The study shows a significant association, but not a clear cause and effect relationship, said Dr. Jane Raymond, a medical oncologist specializing in breast cancer at Allegheny General Hospital in Pittsburgh’s North Side. Raymond said that is the most important thing for women to take away from the study.

“The data is pretty significant in terms of the higher percentage of women getting breast cancer,” Raymond said. “It’ll be important to find out more. There needs to be more research.”

Raymond said studies linking hair dyes — especially dark colors — to cancers like lymphoma and bladder cancer have been emerging for decades. None has been conclusive.

When it comes to what is making the dyes and straighteners so toxic, though, “that’s the question nobody really knows the answer to,” Raymond said.

The study’s authors told Time Magazine that the greater increase in cancer in black women could be because more black women reported using chemical straighteners — 74% of black women surveyed, as opposed to 3% of white women. The authors also hypothesize that thicker, coarser hair may absorb more dye, and that the products used by black women may possibly contain more harmful products.

With hundreds of brands containing a myriad of chemicals, formulas for hair products are constantly changing. Right now, Raymond said it’s impossible to pinpoint an exact ingredient or product that is driving the trend.

Beauty products, in general, are not strictly regulated by the Food and Drug Administration. Cosmetic products do not need FDA approval before they go to market, with the exception of color additives. According to federal law, products can only be deemed poisonous once they’re already on the market.

Moving forward, Raymond said women reading the study shouldn’t panic, adding that continued diet, exercise and regular breast exams are much more important factors to pay attention to.

“Everything in life has risks and side effects,” she said.