Personal use of hair dyes does not appear to raise the risk of most cancers, US researchers say.

But their analysis of Women’s Health Study data reveals a small elevated risk in ovarian cancer, three types of breast cancer and basal cell carcinomas (BCC) that warrant further study, they write in the BMJ.

“This [study] offers some reassurance against concerns that personal use of permanent hair dyes might be associated with increased cancer risk or mortality,” said the researchers from Harvard Medical School in Boston, Massachusetts.

“However, we did find a positive association for risk of some cancers, including basal cell carcinoma, breast cancer (oestrogen receptor negative, progesterone receptor negative, hormone receptor negative) and ovarian cancer.”