Moderate use of hair relaxers doesn't increase a Black woman's risk of breast cancer, according to a new study.
"While there is biologic plausibility that exposure to some components contained in hair relaxers might increase breast cancer risk, the evidence from epidemiologic studies to date continues to be inconsistent," said lead author Kimberly Bertrand, an epidemiologist and assistant professor at Boston University School of Medicine.
While the overall risk of breast cancer is the same for Black women and white women in the United States, Black women have higher rates of aggressive subtypes.
These include estrogen receptor negative (ER-) tumors, which are diagnosed at a younger age and are more deadly, according to background notes on the study.
Certain hair care products, including relaxers/straighteners, are used more often by Black women. These products may contain estrogens or endocrine-disrupting chemicals, but the link between their use and breast cancer risk has been unclear.
To learn more, researchers analyzed data from a major U.S. study of Black women's health launched in 1995.
They compared breast cancer among women who reported moderate or heavy use of hair relaxers to those who reported little or no use of the products. The study found no association between hair relaxer use and overall breast cancer risk.
"Overall, our results are generally reassuring: We found no clear evidence that hair relaxer use is associated with breast cancer risk for most women," Bertrand said in a university news release.
She added that there was some evidence, however, that the heaviest users of lye-containing products -- those who used them at least seven times a year for 15 or more years -- had about a 30% increased risk of estrogen receptor positive (ER+) breast cancer.
Further research is needed to learn more about the possible connection between the use of certain hair relaxers and breast cancer risk, Bertrand concluded.
The findings were recently published online in the journal Carcinogenesis.
The Environmental Working Group has more on hair straighteners.
SOURCE: Boston University, news release, May 24, 2021