Chemical hair straighteners may cause uterine cancer — studyBy ISSAM AHMED, Agence France Presse

WASHINGTON - A new study released on Monday suggests that women who frequently use chemical hair straightening products may have a risk of uterine cancer that is more than twice as high as those who never do.

Black women, who make up the majority of users of straightening products in the United States, should pay particular attention to the findings, which were published in the Journal of the National Cancer Institute.

Even though additional research is needed to confirm the findings in this understudied field of study, scientists praised the work and called for action.

The study, which was led by cancer epidemiologist Alexandra White of the National Institutes of Health, was an outgrowth of her earlier work, which discovered a connection between permanent hair dye and straighteners and breast and ovarian malignancies.

"We would expect them to have unfavorable health implications for hormone sensitive cancers because we know that these straighteners include many different chemicals, including endocrine disruptors," she said.

That prompted us to expand on our prior research and limit it to uterine cancer.

The most frequent cancer of the female reproductive system, uterine cancer accounts for 3% of all new cancer cases, with more than 65,000 new cases and 12,500 predicted deaths in 2022.

The prognosis is typically good if the cancer is discovered early, but treatment frequently entails removing the uterus, which would make it impossible to have children.

The Sister Study, which is run by the government and aims to uncover risk factors for cancer and other disorders, included more than 33,000 US women between the ages of 35 and 74. Data from this study was used in the new report.

Uterine cancer, which mostly impacts the endometrium, the tissue lining the uterus, affected 378 women throughout the course of the 11-year study. It is believed that having too much of the sex hormone estrogen contributes to type 1, the most prevalent form of the cancer.

Researchers discovered that women who admitted to using hair straightening products during the previous year had a nearly 2-fold increased risk of developing uterine cancer compared to women who had never used them.

For frequent users—defined as those who made more than four uses in the previous year—the connection was even stronger. When compared to women who never used the products, these women had a roughly 2.5 times higher risk of acquiring cancer.

Other hair products, such as dyes, bleach, highlights, or perms, did not show any comparable associations.

Brazilian blowouts

According to White, there are chemicals in these products that behave somewhat like estrogen in the body, interfering with normal hormonal functions that may affect the risk of developing cancer.

Another explanation is that some products contain carcinogens like formaldehyde that break the links between the keratin proteins in hair, altering its structure and straightening it.

Brazilian blowouts were a common keratin treatment at the time the women were enrolled for this study, between 2003 and 2009, albeit their popularity has subsequently reduced. Nevertheless, the study did not ask women explicitly what products they used.

One of the study's advantages, according to White, was that it surveyed women about the goods years before they actually developed cancer. This reduced the likelihood that people would misremember or incorrectly ascribe their exposures.

However, a significant drawback was that they were unable to get data on the brands or particular sorts hair straighteners used, which would have bolstered the evidence.

In addition to more population studies that enroll racially diverse groups and gather data on brands, more laboratory research should be conducted, according to White, to examine the theories about how the chemicals cause cancer.

A accompanying commentary in the journal acknowledged several limitations, but called for evidence-based policy changes and stated the study added to a "growing body of data" showing "hair-straightening products are connected with hormone-related malignancies in women."

The personal care product business, it said, promoted "racialized ideals of beauty" that were Eurocentric and consistently disregarded regulations requiring disclosure of chemical ingredients and formulas.

Agence France Presse