A new study from the National Institutes of Health, National Institute of Environmental Health Sciences investigated the relationship between hair products and the incidence of uterine cancer.
Here's what is known:
Past research has shown that hair products are a way for chemicals that can disrupt your endocrine system to enter into your body and these chemicals are also associated with hormone sensitive cancers such as breast and ovarian cancer.
Many hair products like straighteners and hair dyes contain chemicals like formaldehyde and formaldehyde releasing chemicals that are chemicals known to cause cancer.
Here’s what is not known:
Uterine cancer is a type of cancer that begins in the uterus and has not been studied as much as breast and ovarian cancer. Prior to this study, it was not known whether there is a relationship between chemical hair products and the likelihood of being diagnosed with uterine cancer.
Here’s what was done:
A nationwide initiative established by the National Institutes of Health, National Institute of Environmental Health Sciences called the Sister Study was created back in 2003 to uncover the genetic and environmental causes that lead to breast cancer. The original Sister Study followed the lives of 50,884 women from 2003-2009 who had a sister who had breast cancer. For the study on hair products and uterine cancer, after screening participants of the Sister Study for multiple things that would make some of the participants ineligible, 33,947 women of the 50,884 women were eligible to participate in the hair products and uterine cancer study.
Participants in the study were followed for 10.9 years and they self reported how they use 7 different types of hair products. The 7 hair products were permanent, semi permanent, and temporary hair dyes; bleach; highlights; straighteners, relaxers, or pressing products; and hair permanents or body waves. This study was extremely thorough and even took into account whether the products were applied by a professional, the color of the hair dye, and how long over the participants lifetime they used the product as these types of variables can influence the study results.
Demographics of the study population:
The demographics of the study population consisted of 7.4% Black/African American, 4.4% Hispanic/Latina non-Black, 85.6% non-Hispanic White, and 2.5% were all other races and ethnicities.
Here’s what was found from this study and what we can takeaway:
It was observed that hair straightening product use was positively associated with uterine cancer and there was an increase in this association in participants that frequently used hair straightening products(>4 times a year) vs participants that had never used hair straightening products.
There were no associations observed for other hair products used including permanent dyes, semi permanent dyes, temporary dyes, bleach, highlights, and hair permanents with uterine cancer. This study supports previous notions that hair straighteners play a role in hormone sensitive health outcomes.
Possible ways as to how straighteners can lead to hormone sensitive health outcomes is that higher percutaneous absorption of chemicals have been observed in the scalp compared with other skin such as on the forearm, palm, and abdomen. When chemical straighteners are applied to the hair, it can cause scalp injuries and burns which makes the scalp more permeable to chemicals. After people use chemical straighteners it is likely that hair styling involving heat is performed which can break down the chemicals from the products which leads to potentially higher exposures to the hazardous chemicals.
Due to the high prevalence of straightener use among African Americans and the low representation in this study, more work needs to be done to see if hair products lead to potential health disparities in uterine cancer.
To learn more about this study as well as look at the specific numbers and percentages head to:
Che-Jung Chang, PhD, Katie M O’Brien, PhD, Alexander P Keil, PhD, Symielle A Gaston, PhD, Chandra L Jackson, PhD, Dale P Sandler, PhD, Alexandra J White, PhD, MSPH, Use of Straighteners and Other Hair Products and Incident Uterine Cancer, JNCI: Journal of the National Cancer Institute, 2022;, djac165, https://doi.org/10.1093/jnci/djac165