For eight years, an American study carried out a cohort of 45,000 women and dissected all their habits to measure the impact on their health. Scientists have highlighted a link between hair dyes and the development of breast cancer. To hide the appearance of white hair or simply to change heads, hair coloring is ideal. You can become blonde, brunette, redhead … at will and according to your desires. However, a new American study published in the International Journal of Cancer warns of the dangers of coloring. These would promote the development of breast cancer in women.
For eight years, scientists from the National Institutes of Health followed 45,000 American women, ages 35 to 74, enrolled in the Sister Study. What do all these women have in common? Each of them had a sister with breast cancer . The purpose of the study was to determine the causes of the disease.
Breast cancer: responsible hair colors?
For the purposes of the study, all the participants answered a questionnaire on their health and lifestyle. Answering the researchers’ questions, 22,500 women claimed to color their hair regularly. In addition, one in ten said they used a chemical straightener.
The results fell: women who used a hair product of this type had 9% more risk of getting breast cancer compared to those who did not use it. However, women of color have a 45% higher risk of getting breast cancer compared to white women.
Chemical straighteners: an additional danger for women’s health?
To understand this discrepancy, scientists provide an explanation: 74% of women of color reported using a chemical straightener. Only 3% of white women used it. According to this study, the use of chemical straighteners alone would increase the risk of cancer by 18%.
One of the study’s co-authors, Dale Sandler, also puts forward another hypothesis to The Times: ‘ Thicker hair is likely to absorb more dye.’ But for scientists, this is only a guess for the moment which remains to be verified with other tests.
Breast cancer: should these products be avoided?
For the moment, no recommendation concerning the products to avoid has been made. Alexandra White, epidemiologist and one of the co-authors of the study explains why: ‘ The coloring products contain more than 5,000 different components and their formulas are constantly changing’. It is rather difficult to estimate which products are carcinogenic and which are not.
However, scientists point to aromatic amines, chemical dyes found in large quantities in permanent dyes. They would cause DNA breaks and promote the development of cancers. Aromatic amines are also present in semi-permanent and temporary colors, but in lower doses.
