Hair straighteners’ risk too small for docs to advise against their use

Clarissa Ghazi gets lye relaxers, which contain the chemical sodium hydroxide, applied to her hair two to three times a year.

A recent study that made headlines over a potential link between hair straighteners and uterine cancer is not going to make her stop.

“This study is not enough to cause me to say I’ll stay away from this because [the researchers] don’t prove that using relaxers causes cancer,” Ms. Ghazi said.

Indeed, primary care doctors are unlikely to address the increased risk of uterine cancer in women who frequently use hair straighteners that the study reported.

Among frequent users of hair straighteners – meaning those who used them more than four times a year – the researchers found that women were 2.55 times more likely to be diagnosed with uterine cancer than those who never used these products.

In the recently published paper on this research, the authors said that they found an 80% higher adjusted risk of uterine cancer among women who had ever “straightened,” “relaxed,” or used “hair pressing products” in the 12 months before enrolling in their study.

This finding is “real, but small,” says internist Douglas S. Paauw, MD, professor of medicine at the University of Washington in Seattle.

Dr. Paauw is among several primary care doctors interviewed for this story who expressed little concern about the implications of this research for their patients.

“Since we have hundreds of things we are supposed to discuss at our 20-minute clinic visits, this would not make the cut,” Dr. Paauw said.

While it’s good to be able to answer questions a patient might ask about this new research, the study does not prove anything, he said.

Alan Nelson, MD, an internist-endocrinologist and former special adviser to the CEO of the American College of Physicians, said while the study is well done, the number of actual cases of uterine cancer found was small.

One of the reasons he would not recommend discussing the study with patients is that the brands of hair products used to straighten hair in the study were not identified.

Alexandra White, PhD, lead author of the study, said participants were simply asked, “In the past 12 months, how frequently have you or someone else straightened or relaxed your hair, or used hair pressing products?”

The terms “straightened,” “relaxed,” and “hair pressing products” were not defined, and “some women may have interpreted the term ‘pressing products’ to mean nonchemical products” such as flat irons, Dr. White, head of the National Institute of Environmental Health Sciences’ Environment and Cancer Epidemiology group, said in an email.

Dermatologist Crystal Aguh, MD, associate professor of dermatology at Johns Hopkins University, Baltimore, tweeted the following advice in light of the new findings: “The overall risk of uterine cancer is quite low so it’s important to remember that. For now, if you want to change your routine, there’s no downside to decreasing your frequency of hair straightening to every 12 weeks or more, as that may lessen your risk.”

She also noted that “styles like relaxer, silk pressing, and keratin treatments should only be done by a professional, as this will decrease the likelihood of hair damage and scalp irritation.

“I also encourage women to look for hair products free of parabens and phthalates (which are generically listed as “fragrance”) on products to minimize exposure to hormone disrupting chemicals.”