Research: Hair straightening products are associated with an increased risk of uterine cancer

The use of hair straightening products may significantly increase the risk of uterine cancer in women who use them frequently, a major new US scientific study has concluded, the first to make this association.

The researchers, led by Dr Alexandra White of the US National Institute for Environmental Health Security (NIEHS), who published the paper in the journal of the National Cancer Institute, according to Reuters and the New York Times, analysed data on nearly 34,000 women aged 35 to 74 over a period of about 11 years, during which 378 were diagnosed with uterine cancer.

It was found that the likelihood of developing this cancer was about two and a half times higher for women who had used hair straightening products more than four times in the previous year. Less frequent use of such products was associated with only a marginally increased risk of cancer.

“We estimated that by age 70 years, 1,64% of women who had never used hair straighteners developed uterine cancer, but the rate was increased to 4,05% for those who used them frequently. However, it is important to bear in mind that this cancer is relatively rare,” said White.

Previous research had shown that hair-straighteners contain chemicals that disrupt endocrine function. In the past, such products have also been associated with a higher risk of breast, ovarian and other hormone-sensitive cancers.

“Our findings represent the first epidemiological evidence of the association between the use of isotonic products and uterine cancer. Further research is needed to identify specific chemicals responsible for this association,’ the researchers said. Substances such as parabens, bisphenol A, certain metals and formaldehyde, which have been found in isoflavones, may contribute to the increased risk of cancer.

‘However, other hair products such as hair dye or perms did not seem to increase the risk of uterine cancer. This type of gynaecological cancer has generally been on the increase in recent years, particularly in its most aggressive form.

According to the US National Cancer Institute, about 66,000 new cases of uterine cancer are expected in 2022, accounting for 3.4% of all new cancer cases in the country this year. It is also projected that this cancer will account for approximately 12,550 deaths or 2.1% of all cancer deaths in the US in 2022. African-American women make proportionately much more frequent use of hair straightening products and therefore are at greater risk, according to scientists.