Dark Hair Dye May Increase Breast Cancer Risk

Numerous environmental factors—from smoke to the food we eat—are known to increase the risk of certain cancers. While it is well understood that BRCA mutations can increase the risk of breast and gynecological cancers, other factors that may increase cancer risk among women who have not been thoroughly explored.

A study published in Carcinogenesis explored the potential impact of certain hair products on breast cancer risk among African American and Caucasian women. Specifically, the investigators looked at hair dyes, hair relaxers, and cholesterol-based hair care products.

While breast cancer rates have been decreasing, it remains a large driver of mortality among women. Many studies have found that African American women have a higher incidence of breast cancer compared with patients of other racial or ethnic backgrounds; however, the reasons remain unknown.

Previous findings from preclinical studies suggest that exposure to certain compounds found in hair products can play a role in developing cancer, but these studies have included limited populations, were mainly focused on hair dyes, and have not resulted in confirmed findings.

Included in the new study were 4285 women with breast cancer and control patients aged 20 to 75 who were included in the Women’s Circle of Health Study.

The authors gathered sociodemographic information that could influence cancer risk, including family and personal health history, prenatal exposures, reproductive history, and hormone use. They also collected lifestyle exposure data, including the use of hair products, tobacco exposure, alcohol intake, physical activity, and vitamin use. Breast cancer characteristics were also noted.

The authors specifically looked at breast cancer risk alongside the use of hair dyes, chemical relaxers, and deep conditioning creams that included cholesterol or placenta, according to the study.

The investigators found that dark brown or black hair dyes were linked to a 51% increased risk of breast cancer among African American patients. The use of darker hair dye was also linked to a 72% increased risk of estrogen receptor positive breast cancer among this population, according to the study.

There was a 74% increased risk of breast cancer among Caucasians who used chemical relaxers or straighteners. The authors noted some differences in cancer risk by estrogen receptor status.

These findings suggest that there may be a link between hair products and breast cancer risk, according to the study.

The authors said that additional studies are needed to further determine the link between hair products and the development of breast cancer, and how to reduce the risks, the study concluded.