An American study establishes for the first time a link between the risk of uterine cancer and the frequent use of hair straightening or straightening products.
Offered by many hair salons, hair straightening chemicals are not trivial. According to a study by the American Institute of Environmental Health Sciences (NIEHS) published Monday, October 17, they can significantly increase the risk of developing uterine cancer with frequent use.
To reach this conclusion, 33,497 American women aged 35 to 74 were studied in this research. They were followed for nearly eleven years, during which time 378 uterine cancers were diagnosed.
To put this is context: uterine cancer is relatively rare but is increasing. We estimated an absolute risk of about 1.6% among non-users but about 4% among women who used these products >4 times/year
— Alexandra White (@alexandrajwhite) October 17, 2022
“We estimated that 1.64% of women who have never used smoothing products would develop uterine cancer before the age of 70; but for frequent users, this risk rises to 4.05%”, explains on Twitter the epidemiologist Alexandra White, main author of this research work. Note that in the study, frequent use was defined as more than four uses per year.
Alexandra White points out that “uterine cancer is relatively rare” but on the increase. In the United States, it represents about 3% of all new cases of cancer but is also the most common of the female reproductive system, with an estimated 65,950 new diagnoses in 2022.
Endocrine disruptors involved
The incidence rates are particularly worrying among black women, precisely identified as users of smoothing or straightening products, including at a young age. The NIEHS study shows that 60% of participants who said they had used this type of cosmetic also indicated that they were part of the black American community. Knowing that the research results showed that ethnicity was not decisive in itself.
According to Alexandra White, the conclusions of this study are in line with previous research having shown links between these products and other cancers, in particular of the breast or the ovaries. These cosmetics are particularly likely to contain chemicals known as endocrine disruptors, which disrupt hormonal functioning.
That’s why the NIEHS researchers believe that “further research is warranted to identify the specific chemicals underlying this observed association” between hair straighteners and uterine cancer. Suspects are already among the list of ingredients: parabens, bisphenol A, metals and formaldehyde.