Chemicals in products used to colour or wave hair could be the cause of higher levels of bladder cancer observed in hairdressers, researchers have concluded. A study published online in the journal Occupational and Environmental Medicine linked frequency of dye and perm use to raised levels of carcinogens found in hairdressers’ blood.

Gabriella M Johansson and others. Exposure of hairdressers to ortho- and meta-toluidine in hair dyes, Occupational and Environmental Medicine, published online first 9 June 2014.  doi:10.1136/oemed-2013-101960. Medical News Today. Risks 659.