Hair Dyes Linked to Risk of Bladder Cancer
Increased risk seen in hairdressers, barbers; no clear evidence of increased risk from personal use of hair dyes
THURSDAY, March 27 (HealthDay News) -- Hairdressers and barbers may be at an increased risk of bladder cancer, an occupational hazard due to exposure to carcinogens in some types of hair dyes, according to a special report published in the April issue of The Lancet Oncology.
The International Agency for Research on Cancer (IARC) in Lyon, France, brought together 17 scientists from seven countries in February this year to reassess the carcinogenicity of some aromatic amines and hair dyes, and analyzed the risk to hairdressers and barbers due to occupational exposure, as well as the risk from personal use of hair dyes.
The working group reaffirmed the carcinogenicity of some aromatic amines and added several additional aromatic amines to the list. Benzidine, 4-aminobiphenyl, 2-naphthylamine and ortho-toluidine, 4,4'-Methylenebis(chloroaniline) were classified as Group 1 human carcinogens, while 4-Chloro-ortho-toluidine was reaffirmed as a Group 2A probable human carcinogen.
"Many new epidemiological studies on cancer in hairdressers, barbers and beauticians have been published since the last IARC assessment. A small, but consistent, increase in the risk of bladder cancer was reported in male hairdressers and barbers," the authors write. "Because of few supporting findings by duration or period of exposure, the Working Group considered these data as limited evidence of carcinogenicity and reaffirmed occupational exposures of hairdressers and barbers as 'probably carcinogenic to humans.'"