Women who use chemical hair straightening products are at higher risk of uterine cancer

Women who use chemical hair straightening products are at higher risk of uterine cancer

Women who used chemical hair straightening products had a higher risk of uterine cancer than women who did not report using these products, according to a new study from the National Institutes of Health. Researchers found no link to uterine cancer with other hair products the women reported using, including hair dyes, bleaches, highlights or perms.

The study data includes 33,497 U.S. women ages 35 to 74 who participated in the Sister Study, a study led by the National Institute of Environmental Health Sciences (NIEHS), part of the NIH, that aims to identify risk factors for breast cancer and other health conditions. The women were followed for almost 11 years and during this time 378 cases of uterine cancer were diagnosed.

The researchers found that women who reported using hair straightening products frequently, i.e.

We estimated that 1.64% of women who never used hair straighteners would develop uterine cancer by age 70; but for heavy users this risk increases to 4.05%. This doubling rate is worrying. However, it is important to put this information into context – uterine cancer is a relatively rare type of cancer.”

Alexandra White, Ph.D., head of the NIEHS Environmental and Cancer Epidemiology Group and lead author of the study

Uterine cancer accounts for approximately 3% of all new cancer cases, but is the most common cancer of the female reproductive system, with an estimated 65,950 new cases in 2022. Studies show that incidence rates of uterine cancer have been increasing in the United States, particularly among Black women.

According to the study published in the Journal of the National Cancer Institute, about 60% of participants who reported using hair straighteners in the previous year were self-identified Black women. Although the study did not find that the association between hair straightener use and incidence of uterine cancer varies by race, the negative health effects may be greater among black women due to the higher prevalence of use.

"Because Black women use hair straightening or relaxing products more frequently and tend to start using them earlier than other races and ethnicities, these findings may be even more relevant to them," said Che-Jung Chang, Ph.D., an author on the new study and a research associate in the NIEHS Division of Epidemiology.

The results are consistent with previous studies showing that hair straighteners may increase the risk of hormone-related cancers in women.

The researchers did not collect information about brands or ingredients of the hair products the women used. However, they point out in the article that several chemicals found in hair straighteners (such as parabens, bisphenol A, metals and formaldehyde) may contribute to the observed increased risk of uterine cancer. Exposure to chemicals from the use of hair products, particularly hair straighteners, may be more concerning than other personal care products due to increased absorption through the scalp, which can be exacerbated by burns and lesions caused by hair straighteners.

“To our knowledge, this is the first epidemiological study to examine the association between hair straightener use and uterine cancer,” White said. “Further research is needed to confirm these findings in different populations, to determine whether hair products contribute to health disparities in uterine cancer, and to identify the specific chemicals that may increase cancer risk in women.”

This team previously found that permanent hair dyes and hair straighteners can increase the risk of breast and ovarian cancer.

Source:

National Institutes of Health

Reference:

Chang, C.J., et al. (2022) Use of straighteners and other hair products and incident of uterine cancer. JNCI: Journal of the National Cancer Institute. doi.org/10.1093/jnci/djac165.

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