In October 2017 researchers from the USA published their review of the medical scientific literature to assess the association between the use of hair dyes and risk of leukaemia. A total of 20 studies were included in the review. Results showed that ever-use of hair dye did not appear to be a significant risk factor for leukaemia. However, a significantly increased risk of leukaemia did appear to be associated with the use of permanent hair dye and dark hair dye, hair dye use in males, hair dye use pre-1980, and hair dye use for over 15 years. The researchers concluded by stating that hair dye use in certain situations did appear to be associated with a significantly increased risk of leukaemia, but that further research was required to determine whether there was an association between hair dye use and leukaemia or whether these findings were due to methodological limitations in the studies reviewed.
Towle KM et al. Personal use of hair dyes and risk of leukemia: a systematic literature review and meta-analysis. Cancer Med. 2017 Oct;6(10):2471-2486