Hair straightening chemicals linked to higher uterine cancer risk, U.S. study says


OCTOBER 18, 2022

Women who used chemical hair straightening products were at higher risk for uterine cancer compared to women who did not report using these products, a new study says. Photo by HelenOnline/Wikimedia Commons

Women who use chemical hair straightening products are at higher risk for uterine cancer compared to women who do not use these products, a new study from the National Institutes of Health says.

The researchers found no similar association with uterine cancer for other hair products that the women reported using, including hair dyes, bleach, highlights and perms.

The findings appeared Monday in the Journal of the National Cancer Instutute.

No information was collected on brands or ingredients in the hair products used by the women participating in the study. But the researchers noted several chemicals found in straighteners, such as parabens, bisphenol A, metals and formaldehyde, may be contributing to the increased uterine cancer risk.

They also cautioned that chemical exposure from using hair products, especially straighteners, may be more concerning than other personal care products because increased absorption through the scalp may be exacerbated by burns and lesions caused by straighteners.

The study included data from 33,497 U.S. women, ages 35-74, participating in the Sister Study. This research, led by NIH’s National Institute of Environmental Health Sciences, seeks to identify risk factors for breast cancer and other health conditions.

“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%,” Alexandra White, the study’s lead author and head of the NIEHS Environment and Cancer Epidemiology group, said in a news release.

While this doubling rate is concerning, White said, it is important to put this information into context: uterine cancer is a relatively rare type of cancer.

The National Cancer Institute estimates a total of 65,950 cases of uterine cancer in 2022 nationwide, representing 3.4% of all new U.S. cancer cases this year. And NCI projects 12,550 deaths this year from uterine cancer, or 2.1% of all U.S. cancer deaths.

Yet, the scientists cited previous research showing incidence rates of aggressive types of uterine cancer have been rising in the United States, particularly among Black women.

Over the course of nearly 11 years, 378 uterine cancer cases were diagnosed among the study’s participants.

Women who reported frequent use of hair straightening products, which was defined as more than four times in the previous year, were more than twice as likely to develop uterine cancer compared to individuals who did not use the products, the release said.

According to the study, about 60% of the participants who reported using chemical hair straighteners in the previous year were self-identified Black women.

The researchers said the study did not find the relationship between use of chemical hair straightener and uterine cancer incidence differed by race.

Instead, they explained that adverse health effects may be greater for Black women because they tend to use the products more frequently and start using them at earlier ages than other races and ethnicities do.

And this may make the study’s findings even more relevant to Black women, the scientists said.

Lead author White said the researchers believe this is the first epidemiologic study to explore the relationship between chemical hair straightener use and uterine cancer.

She said more research is needed to confirm the findings in different populations and to identify the specific chemicals that may be increasing the risk of cancers in women.

In 2019, the research team found that permanent hair dye and straighteners may increase breast and ovarian cancer risk.

Courtesy: UPI News