Does hair relaxer cause breast cancer in black women?

No, according to a new study by epidemiologist Lynn Rosenberg of Boston University’s Slone Epidemiology Center. Rosenberg and her team studied 48, 167 black women from all over the country who replied to questionnaires mailed out every two years. The women in the Black Women’s Health Study were aged 21 to 69 when the study began in 1995. Rosenberg tracked what happened to women who used hair relaxers containing lye (sodium hydroxide) or calcium hydroxide, guanidine carbonate or thioglycolic acid between 1997 and 2003.