Despite previous studies that indicated that people who use hair dye have an augmented risk of cancer, especially bladder cancer and breast cancer, in the largest study to date, researchers could not confirm this link. The study appeared in the British Medical Journal.

In this study, researchers followed 117,200 women from the US over 36 years. The results found no correlation between hair dye use and the risk of developing most cancers.

However, the researchers did observe a positive association between permanent hair dye and the risk of basal cell carcinoma, hormone receptor-negative breast cancer (ER-, PR- and ER-/PR-), and ovarian cancer. Furthermore, the study found evidence for heterogeneity due to natural hair color: an increased risk of Hodgkin’s lymphoma was only observed in women with naturally dark hair, and a higher risk of basal cell carcinoma was especially observed in women with naturally light hair, the researchers noted.

“The present prospective cohort study offers some reassurance against concerns that personal use of permanent hair dyes may be associated with an increased risk of cancer or mortality. Nevertheless, we also found a positive correlation for the risk of some cancers,”  said Eva Schernhammer, Head of the Department of Epidemiology at the Medical University of Vienna via a press release.

Moreover, the researchers noted that the current findings are limited to US white women and may not extend to other populations.

“Our results justify further prospective validation,” added Schernhammer. “This depends on different populations and countries, different susceptibility genotypes (e.g. NAT1 or NAT2), cancers if different genotypes and molecular genetic phenotypes, different exposure settings (personal use vs. occupational exposure), different time points and different colours of the permanent hair dyes used (dark dyed vs. light dyed), with refined exposure estimates and should be interpreted in the light of the totality of the evidence.”

Credit: Original article published here.