Breast cancer, new data on the relationship with dyes and straightening hair products – Repubblica.it

Permanent hair dyes and straightening products would increase the risk of developing breast cancer, particularly in African American women. To support it a large study of the National Institutes of Health published today on International Journal of Cancer which reignites the debate around the issue. It is, in fact, a topic that periodically returns to the fore, so far without the existence of solid scientific evidence. Especially after Kefah Mokbel, surgeon at the Princess Grace Hospital in London and author of several studies in molecular genetics in 2017, stated with a tweet that there was a relationship between the use of hair dyes and the risk of developing breast cancer. . According to Mokbel, the risk would increase by 14% for a monthly use of hair dye, but he himself underlined that other studies were necessary, since nobody reached a clear answer.

The new study

Now this new analysis, taking into consideration a very large sample of almost 50 thousand women, seems to finally provide some evidence to think about. Using data from the women of the Sister Study – a cohort study that aims to identify environmental and family risk factors for breast cancer in over 50 thousand sisters of women who have had the disease – researchers from the National Institute of Environmental Health Indeed, Sciences (NIEHS) found that women who regularly used permanent hair dye (in the year prior to their involvement in the survey) were 9% more likely to develop breast cancer than those that they had never used it. Furthermore, among African American women, the use of permanent dyes every 5-8 weeks or more has been associated with an increased risk of 60% breast cancer compared to an 8% increase for white women. The increase is, on the other hand, a minimal or zero result with the use of semi-permanent dyes (which may contain oxidants in lower quantities than permanent ones) and temporary (which wash away after one or two shampoos).

We cannot speak of a causal link

"Hair dyes contain various chemicals that can act as carcinogens and endocrine disruptors and therefore can be important factors for breast cancer risk," he explains to Republic – Breast Health Alexandra White, author of the study and head of the NIEHS Environment and Cancer Epidemiology Group. "Researchers have long studied the possible link between hair dye and cancer, but the results have been inconsistent. In our study, we investigated the exposure to these products by nearly 50,000 women, both African American and white, who did not have a cancer diagnosis. We observed a higher risk of breast cancer associated with the use of hair dye: the effect was stronger in African American women, particularly those who used these products frequently. Obviously this is a correlation and not a cause-and-effect connection, ”White points out.

Smoothing products and increased risk

In particular, an interesting discovery was the association identified between the use of smoothing chemicals for hair and the development of breast cancer: those who had used these hair products at least every 5-8 weeks had about 30% in more likely to develop breast cancer. "This is a statistically significant increase, comparable to that observed for other established breast cancer risk factors, such as alcohol and obesity," says White. While the association was similar in African American and white women, the use of these products was much more common among African American women. "In any case, this association should be further investigated. Furthermore, further studies are needed to identify the specific components that contribute to increasing the risk ".

What to do?

Faced with these results it is inevitable to ask what to do. Should women stop dyeing or smoothing their hair? "They simply need to be informed that the use of these products could be associated with an increased risk of breast cancer in order to make their own decisions," says White. "For example, they may choose to use semi-permanent or temporary products. In any case, there are many factors that can potentially help develop breast cancer: avoiding these products could be just one of many things you can do to reduce your risk of breast cancer. " Already in 2107 Mokbel, together with his tweet, although he stressed that it was not a cause-and-effect connection, had offered a series of tips: for example to reduce the number of colors to 2-6 per year at most or to prefer natural dyes (such as henna) that contain a minimum concentration of potentially carcinogenic compounds, such as aromatic amines. In any case, we must not forget the importance of many other factors, such as maintaining the right weight, carrying out physical activity, limiting the consumption of alcohol and above all using screening for the early detection of breast cancer.Photo by Arturs Budkevics from Pixabay