Many hair products contain endocrine‐disrupting compounds and carcinogens potentially relevant to breast cancer, said the report. Products used predominately by black women may contain more hormonally‐active compounds, it also said.
However, the Personal Care Product Council noted that it is a fundamental principle of epidemiology that association is not the same as causation; one does not necessarily lead to the other.
“It is important to note that the study’s authors Dale Sandler, PhD and Alexandria White, PhD, researchers at the Epidemiology Branch of the National Institute of Environmental Health Sciences (NIEHS), urged caution when interpreting the study results. They state, ‘we are exposed to many things that could potentially contribute to breast cancer, and it is unlikely that any single factor explains a woman’s risk. The authors went on to say, ‘researchers have been studying the possible link between hair dye and cancer for a long time, but results have been inconsistent,’" observed PCPC.
“The majority of the cohort studied were non-Hispanic white, well educated, and economically well off. Women recruited for the study were at higher risk for breast cancer. While these women had no personal history of breast cancer, they had at least one sister who had breast cancer. Therefore, the conclusions of this study cannot necessarily be applied to the broader population. Clearly, further research is needed."
According to PCPC, in the study, many of the associations linking hair dyes/straighteners and breast cancer are not statistically significant; furthermore, the association reported for current use of permanent hair dye and breast cancer are not seen when past use of hair dye is taken into account. For example, while the study reports an association for black women who used hair dye in the 12 months prior to enrolling in the study, no association is seen in those same women who used hair dye prior to that 12-month period, regardless of duration of use.
“Hair dyes are one of the most thoroughly studied consumer products on the market. As with all cosmetics and personal care products, companies are required to substantiate the safety of hair dyes and straighteners and individual ingredients before marketing to consumers, and the labeling of those products must be truthful and not misleading," concluded PCPC. “Consumers have a right to know the facts about the products and ingredients they use, however, they also have a right to understand. The Personal Care Products Council shares safety information on our science and safety website, www.cosmeticsinfo.org.”
Another hair health issue made Happi headlines in May 2019 regarding the regulation of lead acetate in hair dye, as reported here.