Study reveals link between chemical hair straighteners and uterine cancer

The news has not been a very comforting source for style and beauty lovers as of late. And while there are still plenty of editor-approved beauty hacks and products that are safe and can make your life easier, it’s reports like the one that found sports bras may contain high levels of BPA and a new study that connects uterine cancer to the use of chemical hair straightening products, also known as relaxers, that have women thinking twice about their once commonplace routines.

In general, uterine cancer rates have been on the rise in the U.S., with a prediction of approximately 65,950 diagnoses and 12,550 deaths in 2022. But the new research regarding the link to chemical hair straightening published by the Journal of the National Cancer Institute raises some interesting points as to who it is affecting and why. 

The study surveyed 34,000 women between the ages of 35 to 74 who came from diverse racial and ethnic backgrounds and found that women who used chemical straightening products in the last year were more than two times as likely to develop uterine cancer by age 70 than those who did not (4% vs 1.6%, respectively.)¹Chang CJ, O’Brien KM, Keil AP, Gaston SA, Jackson CL, Sandler DP, White AJ. Use of straighteners and other hair products and incident uterine cancer. JNCI: Journal of the National Cancer Institute. 2022. doi:10.1093/jnci/djac165

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And although Black women made up a minority of the study participants (7.4%), they were the demographic that was most largely affected, as nearly 60% of that group reported using hair straightening products.

Jason Knight, MD, a gynecological oncologist and director of Gynecologic Oncology at Saint Luke’s Cancer Institute in Kansas City, MO, makes an interesting connection between rising rates of uterine cancer and the affected population, noting that 10 years ago, uterine cancer was more common among white women. But now, the incidence of uterine cancer in Black women has caught up. This is likely for myriad reasons that warrant more research, but Dr. Knight is hopeful that this study will call attention to and prompt further investigation into the disproportionate growth rates. 

Hormone-disruptors and the heat factor

Breast and ovarian cancers, also considered hormone-sensitive types of cancer, have been previously linked to hair straightening chemicals, and now uterine cancer is being added to the list. “Hormone-sensitive” cancers refers to cancers that depend on hormones, such as estrogen, for survival. 

“One of the most significant factors that drive the risk of uterine cancer are elevated levels of estrogen, either from estrogen that’s produced within the body or estrogen that’s absorbed or consumed from the outside world,” says Dr. Knight, explaining that the chemicals in these types of products have been identified as potential hormone disruptors that can throw estrogen and other hormones out of whack. “We don’t know how much exposure is too much, which makes it very difficult to know how stringent a person should be with avoiding certain products or chemicals,” he adds. 

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A few other things to think about: the application of chemical straightening formulas and how they have direct contact to the scalp, plus the heating element that often accompanies these types of treatments. 

Dr. Knight points out how absorbent skin is, and so, the same way that skin care penetrates the skin’s surface for the indicated positive results, so too do chemical hair formulas on the scalp. 

What’s more, heat can be a catalyst for chemical reactions, and while the ingredients on the label could be deemed safe, they may create an entirely different compound with different implications once heat enters the equation.

A strong link, but not causation

Because direct causation has yet to be established between hair straightening chemicals and uterine cancer, it’s not as easy as deciding to discontinue use or never start using these formulas in the first place. Dr. Knight acknowledges that there’s no straightforward or simple answer. 

Instead, he says it’s up to each individual to weigh the current information and make the decisions that are best for them. Most importantly, he notes that without a doubt, this study shows an association between the two, and more importantly shows that “there isn’t concrete evidence to say there’s no reason for concern.”

Uterine cancer signs to look out for

While more research is needed on the topic, you can’t be too cautious. Dr. Knight shares that the number one symptom of uterine cancer is abnormal bleeding. He defines abnormal bleeding as bleeding that happens between periods, is particularly heavy or that happens after menopause. And keep in mind that bleeding isn’t always bright red and there are other types of abnormal discharge that can be cause for concern as well. 

In general, Dr. Knight’s advice is to remain engaged with your healthcare providers, obtain routine health screenings based on age and family history, plus report any new or different symptoms no matter how trivial they may seem.

There’s a bright side

While these statistics may sound scary, there is some good news. “The overwhelming majority of uterine cancers can be detected at an early stage,” says Dr. Knight, adding that approximately 60% to 70% of uterine cancers are diagnosed at stage one, meaning that they have a very high likelihood of being responsive to treatment. If you have concerns or questions about your risk, be sure to make an appointment with your doctor.

Sources:

Chang CJ, O’Brien KM, Keil AP, Gaston SA, Jackson CL, Sandler DP, White AJ. Use of straighteners and other hair products and incident uterine cancer. JNCI: Journal of the National Cancer Institute. 2022. doi:10.1093/jnci/djac165

Clarke MA, Devesa SS, Hammer A, Wentzensen N. Racial and Ethnic Differences in Hysterectomy-Corrected Uterine Corpus Cancer Mortality by Stage and Histologic Subtype. JAMA Oncol. 2022;8(6):895–903. doi:10.1001/jamaoncol.2022.0009

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

Source(s)

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  Chang CJ, O’Brien KM, Keil AP, Gaston SA, Jackson CL, Sandler DP, White AJ. Use of straighteners and other hair products and incident uterine cancer. JNCI: Journal of the National Cancer Institute. 2022. doi:10.1093/jnci/djac165