Boston University Study Finds Increased Uterine Cancer Risk For Black Women Using Hair Relaxer

Another major study on the possible carcinogenic effects of chemical hair straighteners has linked their regular use to increased uterine cancer rates, particularly in Black women.

Researchers who conducted the Boston University Black Women’s Health Study (BWHS) found that postmenopausal women who used hair-relaxing products more than twice a year for at least five years were more than twice as likely to develop uterine cancer than women who never or rarely use them.

Almost 45,000 women with no prior cancer history and an intact uterus were asked about their lifetime use of chemical relaxers, then followed for up to 22 years to track uterine cancer development.

Because many Black women have naturally curly or tightly coiled hair, they use these products more often. Chemical relaxers are heavily marketed specifically to this demographic. 

Hair relaxing products contain potentially harmful chemicals called endocrine disruptors, which are absorbed through the scalp or inhalation and can adversely affect reproductive health. These chemicals include formaldehyde, parabens, and metals. They have been linked in previous studies to other cancers, including endometrial, ovarian, and breast cancer, along with endometriosis, uterine fibroids, and decreased ability to get pregnant.

In late 2022, the National Institutes of Health (NIH) released findings from their landmark “Sister Study,” which tracked more than 33,000 women for over ten years. Three hundred seventy-eight of them developed uterine cancer in that time. The study found that just 1.64 percent of women who never used hair relaxers developed uterine cancer by age 70, compared to 4.05 percent of frequent users. The study did not identify specific chemical straightening products or brands, only the chemicals commonly used in such products.

In response to a March 2023 letter written to the FDA by U.S. Representatives Ayanna Pressley and Shontel Brown, both Black women, the FDA proposed a nationwide ban on formaldehyde and similar chemicals found in hair relaxers. The letter encouraged a “thorough and transparent investigation” to determine whether relaxers contain carcinogenic ingredients.

The FDA, which named formaldehyde a human carcinogen in 2016, is responsible for regulating personal care products. But they are not subject to the same rigorous approval process as food and drugs. The agency is currently accepting public comments about the proposed ban. Once approved, affected products could be removed from store shelves within days.

Radiation oncologist Dr. Onyinye D. Balogun told NBC News that uterine cancer is “one of the few cancers where incidence and mortality are rising” and that it would become the third most common type of cancer among women by 2040.

She noted that chemical hair straightening has been a “rite of passage” for Black women since childhood, motivated by societal pressure to appear “presentable” by changing the texture of their natural hair.

Products other than straighteners marketed to Black women, including perms, lotions, and gels, have also been found to raise the risks of obesity, cardiovascular problems, and other health risks while pregnant.

“There’s a whole history of hair and hair care in the Black community, and some of it stems from issues of racism and discrimination against how women wear their hair and what’s considered a professional hairstyle in office settings, for example, or in school,” said Dr. Kimberly Bertrand, one of the authors of the BWHS study. 

Several states have adopted a version of proposed federal legislation called the CROWN Act, which would prohibit discrimination against a person for their hair or hairstyle based on their race or origin. CROWN stands for “Create a Respectful and Open World for Natural Hair” and was passed in the House in 2022 before stalling.

Hair Relaxer Lawsuits

Less than a week after the NIH’s Sister Study was released in October 2022, Jenny Mitchell of Missouri filed a lawsuit against five hair straightener companies, including L’Oréal and others. It alleged that the chemical relaxers she used for decades gave her uterine cancer, which forced her into a hysterectomy at 28 years old.

Since Mitchell’s lawsuit, thousands of hair relaxer lawsuits with similar claims have been filed. The cases were consolidated into multidistrict litigation (MDL) in a Chicago federal court to manage them more efficiently.

The plaintiffs say that the beauty companies knew or should have known about the risks posed by their products but failed to warn consumers, instead marketing them as safe. A master complaint filed shortly before the cases went into MDL also alleges that the companies took advantage of racial discrimination against Black hair, such as in one L’Oréal ad that stated “how beautiful Black hair can be.”

The plaintiffs’ lawyers believe that the NIH and BWHS studies will convince the judge to let at least some of the cases go to trial without proof that the relaxers caused their clients’ cancer. 

While a new FDA action against formaldehyde wouldn’t lower the plaintiff’s burden of proof linking the relaxers to their cancers in court, the evidence used to implement a ban would likely be admissible.

Anyone who has used these products and developed reproductive cancer or other health issues should consult an experienced hair relaxer attorney who can handle the research, find medical experts to testify, and represent clients if their cases go to trial.