According to a new study published in the British Medical Journal, women having permanent hair dye have an increased risk of developing certain cancers, such as breast and ovarian cancer.
- This observational study establishes a link between the use of permanent dyes and the appearance of breast cancer, ovarian cancer or even basal cell carcinoma.
Are hair dyes really safe for our health? While each year, nearly 315 million hair dyes are sold in France, a new study points to their dangerousness. Published in the British Medical Journal (BMJ), it associates permanent coloring with an increased risk of developing certain cancers: basal cell carcinoma, which is the most common form of skin cancer, ovarian cancer and breast cancer.
The highly concentrated products in question
To better understand the link between cancer risk and the use of permanent hair dye, researchers reviewed data from 117,200 women in the Nurses’ Health Study at Brigham and Women’s Hospital in Boston, USA. United). This is a large prospective cohort study, which includes assessments of exposure to hair dyes.
At the start of the study, none of the women had cancer. They were followed for 36 years. Data analysis showed that the use of permanent hair dyes is associated with a slightly higher risk of basal cell carcinoma, especially in women with naturally light hair.
Using tinctures also increases the risk of developing three types of breast cancer (estrogen receptor negative, progesterone receptor negative, and hormone receptor negative), as well as ovarian cancer. This risk increases with the cumulative amount of dye to which women are exposed. An increased risk of Hodgkin’s lymphoma has also been found with the use of permanent dyes, but only for women with naturally dark hair. “Possible explanations could be that the shades of permanent hair dyes are associated with the concentration of ingredients, with dark colors having higher concentrations.”, advance the authors.
Limits under study
The authors point out that this is an observational study: it therefore does not establish with any certainty the causal link between permanent hair dyes and the risk of cancer.
The study also has several limitations, starting with the lack of racial diversity among the participants, the latter being mainly Americans of Caucasian origin.
Additionally, hair dye exposure assessments ceased relatively early in the follow-up period, so some women were able to start, stop, or change their hair dye after this time, and some non-permanent hair dye users may have incorrectly classified themselves as permanent hair dye users.
Despite these biases, the researchers believe that the study’s findings “provide some assurance against concerns that personal use of permanent hair dyes may be associated with an increased risk of cancer or death”.
This is not the first work to establish a link between coloring and cancer. In December 2019, a study published onInternational Journal of Cancer estimated that women who regularly used hair products such as dyes and relaxers were 9% more likely to develop breast cancer than non-users of these products.
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