Chemical hair-straightening products may increase uterine cancer risk: NIH study
Hair-straightening products may cause uterine cancer, according to new research presented at the 2015 annual meeting of the American Association for Cancer Research.
Uterine cancer has been linked to estrogen replacement, breast-feeding, exposure to the chemical Bisphenol A (BPA), obesity and hormone replacement therapy, among other factors, but new research finds that women who straighten their hair with products containing sodium dehydroacetate (DHA), an ingredient in over-the-counter shampoos, conditioners and hair gels, are more likely to develop the disease — a report in the American Society of Clinical Oncology found that the disease rate in the U.S. has increased by 24 percent since 2005.
In the study, researchers used data from the Surveillance, Epidemiology, and End Results program to compare women with uterine cancer with women who did not have the disease. The study evaluated data from more than 23,000 women in the U.S. between the ages of 40 and 69 who were diagnosed with endometrial cancer, with a comparison group of more than 33,000 women without endometrial cancer.
The researchers assessed the risk of uterine cancer in the women who used hair-strengthening products compared with other consumers who used the products to achieve the same level of hair movement as they did.
The study was conducted by researchers at the National Cancer Institute and the U.S. Environmental Protection Agency.
“There is a substantial body of strong scientific evidence linking the use of DHA to other types of cancer, including ovarian cancer, but to our knowledge, this study is among the first to show a possible link to endometrial cancer,” said senior author Dr. Robert H. Nachtigall, the senior investigator for the NIEHS Program of Molecular Epidemiology of Health and Disease. He said they hope their findings will inform women who may be interested in reducing the risk of cancer by using hair-strengthening products.
“Most of the evidence that DHA is linked to multiple cancers comes from epidemiological studies in animals, which do not exactly mimic human exposure patterns in response to chemical exposures to DHA and other chemicals,” Nachtigall said. “In addition, most of the studies have not taken into