• A new study published in the International Journal of Cancer found women who used permanent hair dyes and chemical straightener were at an increased risk of breast cancer.
• Experts say the results are inconclusive and more definitive studies are needed before doctors will advise changing hair habits.

A new study linking permanent hair dyes and chemical straighteners to increased breast cancer risk had a lot of women worried when it first came out in early December. But should you actually cancel your next appointment at the hair salon?

The research, published by the National Institutes of Health in the International Journal of Cancer, analyzed data from 46,709 women—all of whom had a sister who had been diagnosed with breast cancer, but were cancer-free at the time they enrolled.

Researchers found that women who'd used permanent hair dye in the past year were 9 percent more likely to develop breast cancer than women who hadn't used hair dye. More frequent use increased risk, especially among African-American women: Using permanent hair dye every every five to eight weeks or more was associated with a 60 percent increase in breast cancer risk among African-American women, compared to white women who only had an 8 percent increased risk.

Chemical hair straighteners also came under scrutiny: Researchers discovered that women who used chemical hair straightener every five to eight weeks were 30 percent more likely to develop breast cancer. Rates were similar among white women and African-American women, though hair straightening chemicals were much more commonly used among African-American women in the study.

Researchers speculated that certain chemicals in these hair products disrupted estrogen and other hormones in the body in a way that could increase a person's risk of breast cancer, though the study did not delve into the causation behind the link.

So does this mean you need to swear off hair dye and straightener?

Not necessarily. "These women already inherently have an increased risk of breast cancer because each woman in the study had a sister with breast cancer," Stephanie Bernik, MD, chief of breast surgery at Mount Sinai West, told Women's Health. "Therefore the results are not conclusive."

Still, "the study is provocative and raises questions as to the safety of permanent hair dyes," says Bernik.

While women who are already at higher risk for breast cancer may want to consider altering their habits, "more definitive studies would need to be carried out before doctors would recommend against permanent hair color," Bernik says.

The bottom line: More research is needed on the link between breast cancer, hair dye, and chemical straighteners.