Dying Your Hair Increases
Your Risk Of Cancer
Hairdressers and barbers are at increased risk of developing
cancer – because of their use of hair
dyes. And the risks could extend to personal use of the dyes,
according to international experts.
A review of the evidence by a panel of the International Agency
for Research on Cancer (IARC) in Lyon, France, has found a “small
but consistent risk of bladder cancer in male hairdressers and
barbers".
A second review of the evidence on personal use of hair dyes
found some studies suggesting a possible association with bladder
cancer and with lymphoma and leukaemia.
But the panel found that the evidence was inadequate and concluded
that personal use of hair dyes was “not classifiable as
to its carcinogenicity to humans".
The panel was composed of 17 scientists who met last February
to consider the latest evidence and update advice last issued
by the agency in 1993.
Modern hair dyes are classified as permanent, semi permanent
or temporary dyes. The permanent or oxidative hair dyes represent
80 per cent of the market and consist of colourless “intermediates”
and couplers that, in the presence of peroxide, form the dyes
by chemical reaction.
Dark hair dyes tend to contain the highest concentration of
the colouring ingredients. The use of some such colourants was
discontinued in the 1970s after positive cancer tests in rats.
Dr Robert Baan of the IARC and colleagues say in The Lancet
Oncology: “A small but consistent risk of bladder cancer
was reported in male hairdressers and barbers. 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 haridressers and barbers
as ‘probably carcinogenic to humans'.”
The full report will be published as Volume 99 of the IARC monographs.
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