Researchers at the National Institutes of Health (NIH) have found that women who frequently use permanent hair dyes and chemical straighteners face a higher risk of breast cancer compared to those who don't. The study's data shows risk escalates with more regular use of these products.
Analyzing data from 46,709 women who used permanent hair dye in the year before joining the study, the team determined they were 9% more likely to develop breast cancer than non-users. For African American women using permanent dyes every five to eight weeks or more, the risk rose by 60%—compared to just 8% for white women. Semi-permanent or temporary dyes showed little to no increased risk.
A notable association emerged with chemical hair straighteners: Women using them every five to eight weeks were about 30% more likely to develop breast cancer. While the link was consistent across African American and white women, straightener use was far more prevalent among African American participants.
Co-author Dale Sandler, Ph.D., chief of the National Institute of Environmental Health Sciences (NIEHS) Epidemiology Branch, emphasized that while prior evidence supports the straightener connection, further studies are needed to confirm these findings.
Addressing whether women should avoid dyeing or straightening their hair, Sandler noted: "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 help reduce their risk."
