A new study found disconcerting potential links between cancer and the chemicals for hair dye and for straightening hair.
Women who used permanent hair dye on a regular basis the year prior to enrolling in the Sister Study — which is conducted by the National Institute of Environmental Health Sciences (NIEHS) and focuses on women whose sisters had breast cancer — were 9% more likely to develop breast cancer than those who didn’t use hair dye, according to the National Institute of Health, which houses the NIEHS.
“Researchers have been studying the possible link between hair dye and cancer for a long time, but results have been inconsistent,” said corresponding author and head of the NIEHS Environment and Cancer Epidemiology Group, Alexandra White. “In our study, we see a higher breast cancer risk associated with hair dye use, and the effect is stronger in African-American women, particularly those who are frequent users.”
The findings, which used data from close to 47,000 women involved in the Sister Study, found a 60% increased risk of breast cancer for African-American women who use permanent dyes every five to eight weeks. White women in the same category had just an 8% increased risk.
The findings established little to no increase in risk for breast cancer for those who used temporary or semi-permanent dye.
According to the findings, breast cancer was nearly 30% more likely to develop in those who use chemical hair straighteners every five to eight weeks, and was similarly more pronounced in African-American women — who were found to use straighteners more often — than white women.
“It is unlikely that any single factor explains a woman’s risk,” said co-author and chief of the NIEHS Epidemiology Branch Dale Sandler. “While it is too early to make a firm recommendation, avoiding these chemicals might be one more thing women can do to reduce their risk of breast cancer.”