Study Shows Connection Between Hair Dye and Chemical Straightener Use and Increased Breast Cancer Risk

Article Author: Kira Levenson, Biochemistry Major, Class of 2022, Protect Our Breasts Science Translator

For many women, hair dye and chemical straighteners are regular fixtures in their lives. However, recent research suggests that exposure to the chemicals used in these hair products may have a positive link to increased risk of breast cancer.

Hair dye and chemical straighteners are known to contain a variety of chemicals, many of which are known to be endocrine-disrupting chemicals (EDCs). However, these EDCs can have especially long-lasting effects on women’s health and increase the risk of breast cancer. EDCs interfere with the endocrine system, which manages the body’s hormones and growth responses, among other things. Sometimes this happens by blocking the responses naturally sent by the body, while other times EDCs might send a fake signal and encourage unwanted responses. These exposures are especially potent when they occur during key developmental stages such as puberty and during pregnancy.

One study from December 2019 “evaluated the association of hair dye and straightener use with breast cancer in a large, prospective cohort of US women,” (Eberle et. al, 2019) with data collected from 2003-2009 and follow-up continuing through September 2016. 

Some key findings from this study include: 

• Observed levels of risk were highest overall for women who had used permanent hair dye or straighteners, and for women who had applied straighteners to others (prior to the start of the study).
  • Overall, women who used permanent hair dye were 9% more likely to develop breast cancer.
• Observed levels of risk were higher specifically for Black women, with varying risk levels for women of different ethnicities overall.
  • Regular permanent hair dye use was correlated to a 60% increased risk of breast cancer among Black women.
  • Compare this: 8% increased risk among white women who regularly used permanent hair dye.

The study also makes clear that these exposures are not equal across populations, and point out that Black women are disproportionately affected. Researchers note that while the majority of previous studies focusing on this research have been inconsistent in their findings, these previous studies have been largely limited to white women.  The researchers also note differences in marketing and use patterns between women of different ethnicities, suggesting further external influences.

While more research is needed to confirm their results, the researchers note that future findings could prove to have a “substantial public health impact”. If you use hair dye or chemical straighteners, you don’t have to change your habits overnight! The most important tip is to keep a closer eye on what’s in your hair products. Connect with the EWG SkinDeep Database here to check the safety of your hair and other personal care products and find new, safer alternatives! Information and awareness are valuable tools for protecting both your health and the health of future generations. 

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Source:

Eberle CE, Sandler DP, Taylor KW, White AJ. Hair dye and chemical straightener use and breast cancer risk in a large US population of black and white women. Int J Cancer. 2020 Jul 15;147(2):383-391. doi: 10.1002/ijc.32738. Epub 2019 Dec 3. PMID: 31797377; PMCID: PMC7246134.

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