Researchers from Rutgers University recruited 4,285 African-American and Caucasian women, both with and without breast cancer, who were aged 20 to 75. The study authors examined the established probable breast cancer risk factors, such as personal health history, reproductive history, and hormone use, along with the use of personal hair products, including hair dyes, chemical relaxers/straighteners, and deep conditioning creams containing cholesterol or placenta.
And here’s what they discovered: Dark-hued hair dyes (dark brown or black) were associated with a 51 percent increased overall risk of developing breast cancer among African-American women and a 72 percent increased risk of estrogen-receptor-positive breast cancer among African-Americans. The medical investigators also concluded that the use of chemical relaxers or straighteners was associated with a 74 percent increased risk among Caucasians, with some differences in breast cancer risk observed by estrogen-receptor status.
“Our findings highlight the need for further examinations of the link between the use of hair products as important exposures that may contribute to the development of breast cancer, as well as ways to reduce the associated risks,” stated the researchers in a press release.
Jack Jacoub, MD, medical oncologist at MemorialCare Cancer Institute at Orange Coast Memorial Medical Center in Fountain Valley, Calif., tells Yahoo Beauty that he is not completely surprised by these results, which were published in the online issue of Carcinogenesis.
“Anything that is accumulative or repetitively done that involves any potentially harmful chemical, over time” could possibly lead to the development of cancer “in a predisposed individual,” he states.
However, Jacoub quickly points out that cancer, in general, is a “complex condition where there are a lot of different factors that are all working together, to some degree.”
In the case of breast cancer, other common risk factors include genetics, having a family history, race and ethnicity, and having dense breasts, as well as drinking alcohol, being overweight or obese, and being physically inactive, according to the American Cancer Society.
“And then the factor — that is not as well understood — is the dance between these factors and what eventually leads to cancer,” continues Jacoub. “It is uncommon to have just one factor, unless someone has a fairly profound heredity disposition to cancer.”
Keep in mind that the study authors solely focused on the issue of hair products, notes Jacoub. “There’s very little evidence to directly link it with breast cancer because it’s a very hard thing to prove,” he notes. “It requires thousands of patients to make the observation and then to be able to statistically prove there’s a relationship.”
His suggestion: Become more diligent about controlling your environment.
“Be careful what you ingest and what you put on yourself,” stresses Jacoub. Along with maintaining a healthy weight, “don’t smoke, don’t drink, watch your diet, cut out animal proteins if you can, and eat a more plant-based diet,” he suggests. “Know exactly what’s in everything, like medicines, vitamins, herbals, along with deodorants, hair dyes, and hair relaxers — it’s an interplay of all these things.”
Read more from Yahoo Style + Beauty:
- Mom Who Beat Cancer Goes Viral for Epic Exit From Oncology Wing
- Vigorous Exercise Helps Lower Breast Cancer Risk for Both Younger and Older Women
- Lots of Sleep Tied to Worse Breast Cancer Survival Odds