A new study by researchers at the Medical University of Vienna has determined consumers who regularly dye their hair are not at a higher risk of developing cancer, with some exceptions.
In the largest survey of its kind, which followed more than 117,000 white women from the US over the age of 36, the team found regular hair colouring was not conducive to most cancers.
However, it did find a positive association for the risk of basal cell carcinoma, hormone receptor-negative breast cancer and ovarian cancer.
“The present prospective cohort study offers some reassurance against concerns that personal use of permanent hair dyes may be associated with increased risk of cancer or mortality,” said Eva Schernhammer, the team’s lead researcher.
“Nevertheless, we also found a positive correlation for the risk of some cancers.”
In a study published last year, of almost 47,000 participants, scientists at the National Institutes of Health also found women who use permanent hair dye and chemical hair straighteners have a higher risk of developing breast cancer.
Researchers said those that regularly use permanent hair dye are 9% more likely to develop breast cancer than those that did not.
However, Schernhammer said her team’s results need further validation.
“This depends on different populations and countries, different susceptibility genotypes, eg NAT1 or NAT2, cancers of different genotypes and molecular genetic phenotypes, different exposure settings – personal use versus occupation use – different time points and different colours of the permanent hair dyes used, with refine exposure estimates and should be interpreted in the light of the totality of the evidence.”
The International Agency for Research on Cancer (IARC), part of the World Health Organization, has classified occupational exposure to hair dyes as a probable human carcinogen.
However, personal use could not be classified.
