Chemical hair straightening products are linked to an increased risk of uterine cancer in a new study

By Jacqueline Howard, CNN

(CNN) – Scientists are uncovering new details linking the use of certain hair straightening products, such as chemical relaxers and pressing products, to an increased risk of cancer in women.

Ongoing research has previously suggested that hair straightening chemicals are linked to an increased risk of certain hormone-related cancers, including breast and ovarian cancer, and now a new study links the use of hair straightening products to an increased risk of uterine cancer. The researchers noted that black women may be more affected due to greater use of the product.

The study, published Monday in the journal Journal of the National Cancer Instituteestimates that among women who have not used chemical hair straightening products in the past 12 months, 1.6% develop uterine cancer by age 70, but only about 4% of women who use such hair straightening products – they use it quickly, they got cancer of the uterus at the age of 70. .

Chandra Jackson, study author and researcher at the National Institute of Environmental Health Sciences, said the finding “also suggests that uterine cancer is indeed rare. However, doubling the risk is cause for concern.”

“In this study, women who used frequently in the past year had twice the risk of uterine cancer,” he said. Frequent use was defined more than four times in the past year.

Cancer risk was higher in black women

The new study included data on nearly 34,000 women ages 35 to 74 in the United States who filled out questionnaires about their use of certain hair products, including perms, dyes, relaxers and straighteners. Researchers from the National Institutes of Health also tracked cancer diagnosis rates within the study group.

The researchers found a strong link between hair straightening products and cases of uterine cancer, but the use of other hair products, such as dyes and perms or body waves, was not associated with uterine cancer.

The study data also showed that the link between hair straightening products and cases of uterine cancer was greater in black women, who made up only 7.4% of the study participants, but 59.9% of those who reported always using straighteners.

Several factors play a role in the frequent use of hair straightening products: Eurocentric standards of beauty, social pressures on black and Latina women in workplace settings related to microaggressions and the threat of discrimination, along with the desired universality in changing hairstyles and self-presentation.

“The bottom line is that the burden of exposure is higher among black women,” Jackson said.

“Based on the body of literature in the field, we know that hair products marketed directly to children and black women have been shown to contain many chemicals linked to hormone disruption, and that these products marketed to black women have also been shown to given the tougher chemical formulas,” he said. “Additionally, we know that black women tend to use multiple products at the same time, which may contribute to black women having, on average, higher concentrations of these hormone-disrupting chemicals in their systems.”

The researchers did not collect data on the brands or ingredients of the hair products the women used, but they wrote in the paper that several chemicals identified in the shampoos may have contributed to the increase in uterine cancer seen in their study.

“To our knowledge, this is the first epidemiological study to examine the relationship between straightener use and uterine cancer,” said Alexandra White, director of the National Institute of Environmental Health Sciences and Cancer Epidemiology and lead author of the study. it is said in the news Dushanbe.

“More research is needed to confirm these findings in different populations, determine whether hair products contribute to health disparities in cervical cancer, and identify specific chemicals that may increase the risk of cancer in women.”

“A New and Growing Area of ​​Research”

Tamara James-Todd, an epidemiologist at the Harvard TH Chan School of Public Health, said some ingredients in hair straightening products, especially those used and marketed more by black and Latina women, disrupt chemical hormones. New research, however, has led to some of the first studies to establish a link between hair products and cancer.

“They change our body’s normal hormonal processes. So it makes sense to look at hormone-mediated cancers,” he said, adding that hormone-disrupting chemicals can also affect other parts of the body.

“The problem is that the effects of these chemicals are not only limited to hormonal processes, but they can also affect other systems, including the immune system and our blood vessels. Understanding how these chemicals work outside of the hormonal system, is still a new and growing field, James-Todd told CNN.

“So maybe the way these chemicals work is by changing hormonal responses, but also by changing immune or even vascular responses,” he said. “All of these processes are associated with cancer.”

While the new study is “well done” and shows a link between chemical hair straightening products and an increased risk of uterine cancer, it cannot determine whether the products directly cause cancer, said Dr. Otis Brawley, a professor at Johns Hopkins University Bloomberg. School of Public Health and former chief medical officer of the American Cancer Society, told CNN in an email.

“It’s not able to show causation, it could be pure association,” said Brawley, who was not involved in the new study.

However, “the question of how we solve this is a difficult one. The scientific ideal is a randomized trial of 40,000 or so; 20,000 with regular hair use and 20,000 who never use it and have never used it, and 20 years to they follow,” he said. , added that at the moment, “science is impossible to answer better than the latest research”.

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