The National Institutes of Health (NIH) recently published data from their study, which included 33,497 U.S. women ages 35-74. The women were followed for almost 11 years, and during that time 378 uterine cancer cases were diagnosed.

The researchers found that women who had never used hair straighteners were at a 1.64 % risk of developing uterine cancer, while women who did were at double the risk. Moreover, black women were at 60 % higher risk of developing uterine cancer as straightener use was much more common among African American women.

A study published by the NIH on December 4, 2019, in the International Journal of Cancer suggested that breast cancer risk increased with more frequent use of permanent hair dye and chemical hair straighteners.

Women who used hair-straightening products at least every five to eight weeks were about 30% more likely to develop breast cancer. While the association between straightener use and breast cancer was similar in African American and white women, straightener use was much more common among African American women overall.