Uterine cancer, also known as endometrial cancer, is the sixth most commonly occurring cancer for women around the world, with more than 417,000 cases reported in 2020. WHO research shows that the rate of endometrial cancer has increased globally from 1990 to 2019.
According to a new research published in the Journal of the National Cancer Institute, the use of chemical hair straightening products is associated with an increased risk of uterine cancer. Researchers observed an 80 per cent higher risk of uterine cancer among study participants who had used straightening products, and that risk increased with more frequent use. “Previous studies have found hair product use to be associated with a higher risk of hormone-sensitive cancers, including breast and ovarian cancer; however, to our knowledge, no previous study has investigated the relationship with uterine cancer,” the researchers highlighted.
The research collected data from 33,497 women, aged 35-74, who had earlier participated in a sister study, led by the National Institute of Environmental Health Sciences (NIEHS), part of NIH. The women were followed for almost 11 years and during that time 378 cases of uterine cancer were diagnosed. It was found that women who reported they were using hair straightening products were twice as likely to develop uterine cancer than those who did not use these products. "This doubling rate is concerning. However, it is important to put this information into context - uterine cancer is a relatively rare type of cancer," said Alexandra White, PhD, head of the NIEHS Environment and Cancer Epidemiology group and lead author on the new study. "We estimated that 1.64 per cent 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 per cent," added White.
Though the researchers did not collect information on the brand or ingredients in the hair products that the women used, the paper noted that several chemicals found in straightening products like parabens, bisphenol A, metals, and formaldehyde could be contributing to the increased risk of uterine cancer.