Does the Use of Hair Dyes Increase the Risk of Developing Breast Cancer? A Meta-analysis and Review of the Literature

Background/Aim: Hair dye may contain mutagenic compounds which could be associated with an increased incidence of breast cancer in women who use it. The aim of this study was to examine the association between the personal use of hair dyes and the risk of breast cancer. Materials and Methods: We conducted a literature review of epidemiological studies reporting breast cancer-specific risks among hair dye users versus non-users. The data for the incidence of breast cancer following the 'ever' use of hair dye in studies which met the inclusion criteria was analysed using a meta-analysis. The relative risk ratio (RR) and 95% confidence intervals (CI) were determined. Results: A total of eight case-control studies published between 1980 and 2017 met the selection criteria and were included in the meta-analysis. Compared to non-users, using a random effects model and the Duval and Tweedie's trim and fill procedure to adjust for publication bias in the presence of between studies heterogeneity, the adjusted RR for women using hair dyes was 1.1885 (95% CI=1.03228-1.36835). This indicates an 18.8% increased risk of future development of breast cancer among hair dye users. Conclusion: Although further work is required to confirm our results and clarify potential mechanisms, our findings suggest that exposure to hair dyes may contribute to an increased breast cancer risk.