A research team at Boston University found that frequent and long-term use of lye-based relaxers may increase the risk of breast cancer among Black women, compared with more moderate use, the study’s co-author Dr. Kimberly Bertrand reported in The Conversation.

Her team found that “Black women who used hair products containing lye at least seven times a year for 15 or more years had an approximately 30% increased risk of estrogen receptor positive breast cancer compared with more infrequent users.”

The researchers studied data from Boston University’s Black Women’s Health Study, which followed 59,000 self-identified African American women for over 25 years.

Read more, breast cancer findings