Hair relaxers not associated with increased risk of breast cancer in black women

January 04, 2016

The findings will be published in the May issue of Cancer Epidemiology Biomarkers & Prevention.

Hair dye use has been associated with an increased risk of various cancers in some studies, but these results have generally not been confirmed. The present study is the first to assess hair relaxers in relation to a cancer.

Since millions of women have used hair relaxers, and because the carcinogenic potential of hair relaxers is unknown, Lynn Rosenberg, ScD, associate director of Boston University's Slone Epidemiology Center, and colleagues examined the association of hair relaxer use with breast cancer incidence in the Black Women's Health Study.

The Black Women's Health Study is a follow-up study of 59,000 African American women from across the United States conducted by investigators at Boston University's Slone Epidemiology Center and Howard University Cancer Center. While tracking data from 1997 to 2003, researchers combed through more than 266,000 person-years of follow up data to determine that there is no increase in breast cancer incidence associated with hair relaxer use.

"In the present study of African American women, increases in breast cancer risk were not associated with any categories of duration of hair relaxer use, frequency of use, age at first use, number of burns experienced during use, or type of relaxer used," stated Rosenberg. "Of particular interest, null associations were observed among younger women, who used relaxers at earlier ages and more frequently than older women. Thus, the findings provide empirical evidence that hair relaxers are not carcinogenic to the breast and do not contribute to the higher incidence of breast cancer in young African-American women than in young white women."

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"They mean that premenopausal women with hormone receptor positive low risk breast cancer could consider treatment that is as effective as chemotherapy without having to endure unpleasant side effects and risk losing their fertility. For all women aged under 40, this treatment can be added to chemotherapy to improve outcome further. In all cases tamoxifen, a different kind of hormone treatment, would also be usually be used as standard treatment."

About two thirds of pre-menopausal patients have hormone sensitive breast cancer which equates to around 5,500 women being diagnosed in the UK every year.

Overall 42,000 women are diagnosed with breast cancer every year in the UK. Of these around 80 per cent are over the age of 50.

Kate Law, head of clinical trials at Cancer Research UK, said: "Breast cancer is always a shocking diagnosis but it is particularly sad when its treatment results in women being unable to have children.

"This is a very encouraging finding and suggests breast cancer treatment for some pre-menopausal women could be less devastating while being equally effective as conventional chemotherapy."

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