Oct. 18, 2022 -- Women who use chemical hair straightening products may be at an increased risk for uterine cancer, according to new research from the National Institutes of Health.
Women who use straightening products more than four times per year have the highest risk for developing uterine cancer, according to the study. More specifically, the researchers found that women who used straightening or relaxing products more than four times per year were more than twice as likely to develop uterine cancer compared to those who don't use these products.
Lead study author Alexandra White, PhD, said that about 1.64% of women who don't use chemical hair straightening products develop uterine cancer by age 70. But for frequent users of these products, that risk goes up to 4.05%.
"This double rate is concerning," she said. But "it's important to put this information into context," she noted, as "uterine cancer is a relatively rare type of cancer."
Previous research has linked hair product use, such as hair dye, to increased risks of other hormone-sensitive cancers such as breast cancer. But researchers believe this is the first analysis that examined the use of hair straighteners in relation to uterine cancer.
The study examined hair product usage and uterine cancer incidence during an 11-year period among 33 ,947 women whose ages ranged from 35 to 70. The analysis controlled for variables such as age, race, and risk factors.
Uterine cancer is the ninth most common type of cancer in the United States, according to the National Cancer Institute, with more than 65,000 new cases diagnosed annually. More than 12,000 deaths are caused by uterine cancer each year.
Hair straightening product usage was more common among women with low physical activity and among African American women, the study found.
“Because Black women use hair straightening or relaxer products more frequently and tend to initiate use at earlier ages than other races and ethnicities, these findings may be even more relevant for them,” said Che-Jung Chang, PhD, one of the study authors, in a statement.
The study was funded by the Intramural Research Program of the National Institute of Health and the National Institute of Environmental Health Sciences and was published in the Journal of the National Cancer Institute on Monday.