Hair dye and chemical straightener use and breast cancer risk in a large US population of black and white women

Abstract

Many hair products contain endocrine-disrupting compounds and carcinogens potentially relevant to breast cancer. Products used predominately by black women may contain more hormonally-active compounds. In a national prospective cohort study, we examined the association between hair dye and chemical relaxer/straightener use and breast cancer risk by ethnicity. Sister Study participants (n = 46,709), women ages 35-74, were enrolled between 2003 and 2009, and had a sister with breast cancer but were breast cancerfree themselves. Enrollment questionnaires included past 12-month hair product use. Cox proportional hazards models estimated adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association between hair products and breast cancer; effect measure modification by ethnicity was evaluated. During follow-up (mean = 8.3 years), 2,794 breast cancers were identified. Fifty-five percent of participants reported using permanent dye at enrollment. Permanent dye use was associated with 45% higher breast cancer risk in black women (HR = 1.45, 95% CI: 1.10-1.90), and 7% higher risk in white women (HR = 1.07, 95% CI: 0.99-1.16; heterogeneity p = 0.04). Among all participants, personal straightener use was associated with breast cancer risk (HR = 1.18, 95% CI 0.99-1.41); with higher risk associated with increased frequency (p for trend = 0.02). Nonprofessional application of semipermanent dye (HR = 1.28, 95% CI 1.05-1.56) and straighteners (HR = 1.27, 95% CI 0.99-1.62) to others was associated with breast cancer risk. We observed a higher breast cancer risk associated with any straightener use and personal use of permanent dye, especially among black women. These results suggest that chemicals in hair products may play a role in breast carcinogenesis.Additional Supporting Information may be found in the online version of this article.

Personal use of permanent hair dyes and cancer risk and mortality in US women: prospective cohort study

“…Interestingly, a recent US cohort study observed considerably higher breast cancer risk in black women and a borderline increased risk among white women who used permanent hair dyes,3738 which is largely consistent with our findings among US women with predominantly European ancestry. In particular, this recent study detected potential differences by estrogen receptor status; the risk associated with permanent hair dye appeared to be specifically increased for estrogen receptor negative breast cancer compared with estrogen receptor positive breast cancer 37. Our study, which was based on a larger number of women with breast cancer and more refined confounding control,39 observed similar findings for estrogen receptor negative breast cancers.…”

“…African Americans have higher risks of presenting with estrogen receptor negative and progesterone receptor negative breast cancer than non-Hispanic white people in the US 3536. Interestingly, a recent US cohort study observed considerably higher breast cancer risk in black women and a borderline increased risk among white women who used permanent hair dyes,3738 which is largely consistent with our findings among US women with predominantly European ancestry. In particular, this recent study detected potential differences by estrogen receptor status; the risk associated with permanent hair dye appeared to be specifically increased for estrogen receptor negative breast cancer compared with estrogen receptor positive breast cancer 37.…”

“…Firstly, our cohort was not randomly sampled from US women, but enrolled only healthcare professionals and more than 96% of the women had European ancestry. Therefore, although racial or ethnical disparities in the association between personal permanent hair dye use and risk of certain cancers (eg, breast cancer3738) have been suggested in previous studies, we were not able to investigate heterogeneity across race or ethnicity in cancer risk and mortality in this cohort, limiting the generalizability of our findings. Additionally, compared with the general population, nurses might be more adept at taking precautions while applying hair dyes (eg, following directions, using gloves, keeping track of time, rinsing the scalp thoroughly with water after use), which could limit the generalizability of our findings.…”

The evolving epidemic of breast cancer in sub‐Saharan Africa: Results from the African Cancer Registry Network

“…In Nigeria, Zheng and collaborators found 11.1% of women with breast cancer carried inherited genetic mutations in BRCA1 and BRCA2 , 49 while the prevalence is lower among women of European ancestry. Less established risk factors which are more prevalent among African women, such as the use of hair relaxers and dyes, 8,9 skin lighteners 8 as well as exposure to dichlorodiphenyltrichloroethane (DDT) (an endocrine modulator used for malaria control in many SSA countries), require more comprehensive studies across different African settings 7 …”

Use of Beauty Products Among African American Women: Potential Health Disparities and Clinical Implications

“…1,3 Data has demonstrated in vitro estrogenic and anti-estrogenic activity of these products, but further studies are warranted to investigate in vivo activity.3 Previous studies on the association between hair product use and breast cancer have shown inconsistent results; however, a large national prospective cohort study recently yielded significant results. 1,3,4 The study enrolled 50,888 participants with no history of breast cancer but had a sister with breast cancer. 4 The association between hair dye and chemical relaxer/straightener use and breast cancer risk was examined by ethnicity.…”