Hair-Straightening Chemicals Linked to Uterine Cancer in a New Study that Warns Black Women
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Women who use hair-straightening chemicals are at higher risk for uterine cancer compared to those who don't, according to a new study by the National Institutes of Health.
The study, published Monday, included 33,497 women ages 35-74 and found that participants who used hair straightening products more than four times in the year were more than twice as likely to develop uterine cancer.
After studying the women for 11 years, researchers reported that 378 uterine cancer cases were diagnosed.
"We estimated that 1.64% of women who never used hair straighteners would go on to develop uterine cancer by the age of 70; but for frequent users, that risk goes up to 4.05%," Dr. Alexandra White, lead author of the study and head of the NIEHS Environment and Cancer Epidemiology group, said in a release. "This doubling rate is concerning. However, it is important to put this information into context — uterine cancer is a relatively rare type of cancer."
The National Cancer Institute reports that uterine cancer accounts for 3 percent of all new cancer cases but is the most common cancer of the female reproductive system, with nearly 66,000 new cases expected this year.
Health experts warn that Black women may be affected more due to higher use of chemical hair-straightening products than their counterparts. About 60% of the study participants who reported using straighteners in the previous year were self-identified Black women.
"Because Black women use hair straightening or relaxer products more frequently and tend to initiate use at earlier ages than other races and ethnicities, these findings may be even more relevant for them," said Dr. Che-Jung Chang, author of the study and research fellow in the NIEHS Epidemiology Branch.
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Researchers note that no associations with uterine cancer were found in other hair products that the women reported using, including hair dyes, bleach, highlights, or perms.
While the study did not analyze specific brands or ingredients, it states that several chemicals have been found in straighteners — such as parabens, bisphenol A, metals, and formaldehyde — that could be contributing to the increase in uterine cancer risk after being absorbed through the scalp.
Researchers in this study previously found that permanent hair dye and straighteners may increase breast and ovarian cancer risk.
