Research from the Black Women’s Health Study has found that long-term and frequent users of hair relaxers had roughly a 30% increased risk of breast cancer compared with more infrequent users. Shivani Dave speaks to Dr Kimberly Bertrand, co-investigator of the study and assistant professor of medicine at Boston University, about the research and to journalist Tayo Bero about the effects these findings could have on the black community. Help support our independent journalism at theguardian.com/sciencepod