A study by the National Institutes of Health (NIH) found that women who used chemical hair straightening products had an increased risk of cervical cancer.
This is the first time that the epidemiologic relationship between hair straightening products and uterine cancer has been investigated, and caution is required as the risk increases with frequency of use.
On the 17th of local time, the NIH published the results of the new study.
Chemicals are absorbed through the scalp when using hair products such as hair dye, bleach, and hair straighteners. The researchers followed 33,497 U.S. women aged 35 to 74 years for approximately 11 years to identify risk factors for chemotherapy for breast cancer and other health conditions, resulting in a total of 378 cervical cancers during that time.
The analysis found that women who reported frequent use of hair straightening products (more than four times a year) were more than twice as likely to develop uterine cancer as women who did not use the products.
In contrast, there was no association of uterine cancer with other reported hair products, including dyes, bleach, highlights, or perms.
Although cervical cancer is rare, accounting for only about 3% of new cancer cases, it is common in the female reproductive system, with an estimated 65,950 cases of cervical cancer in the United States by 2022.
The risk of uterine cancer by age 70 for women who had never used a hair straightener was only 1.64%, while the risk increased by up to 4.05% for frequent users of the product.
The incidence of uterine cancer was frequent among black women due to the nature of using hair straightening products. According to a study published in the Journal of the National Cancer Institute, about 60 percent of those who reported using straight products in the previous year were black women.
“The study did not find a racial difference between the use of straight products and the incidence of uterine cancer, but the adverse health effects may be greater for black women because they affect frequency of use,” the researchers cautioned.
These results are consistent with previous studies showing that straight products may increase the risk of hormone-related cancers in women. In previous studies, permanent hair dye and hair straightening products increased the risk of breast and ovarian cancer.
Although the researchers did not collect information on the brands or ingredients of hair products used by women, in their research papers, they noted that parabens, bisphenol A, metals and formaldehyde found in the products may contribute to an increased risk of cervical cancer.