Scientists at the National Institutes of Health found that women who use permanent hair dye and chemical straighteners have a higher risk of developing breast cancer than women who do not use these products. The study suggests that the risk of breast cancer increased with more frequent use of these chemical hair products.
The researchers found, based on data from 46,709 women who regularly used permanent hair dye in the year prior to enrolling in the study, are 9% more likely than women who did not use hair dye to develop breast cancer. Among African-American women, the use of permanent dyes every five to eight weeks or longer was associated with a 60% increased risk of breast cancer compared with an 8% increased risk for white women. The research team found little to no increase in breast cancer risk for semi-permanent or temporary dye use.
An intriguing finding was the link between the use of chemical hair straighteners and breast cancer. The researchers found that women who used hair straighteners at least every five to eight weeks were about 30% more likely to develop breast cancer. While the association between hair straightening use and breast cancer was similar in African American and Caucasian women, hair straightening use was much more common in African American women.
Co-author Dale Sandler, Ph.D., chief of the NIEHS Epidemiology Branch, cautioned that while there is previous evidence to support the association with chemical hair straighteners, these results need to be replicated in other studies.
When asked whether women should stop dyeing or straightening their hair, Sandler said, "We are exposed to many things that could potentially contribute to breast cancer, and a single factor is unlikely to explain a woman's risk. While it's too early to make a strong recommendation, avoiding these chemicals may be one more thing women can do to reduce their risk of breast cancer. “
