Originally published January 26
water found to increase risk of bladder cancer
by M.T. Whitney
(NewsTarget) Drinking, or even immersing yourself
in, chlorinated water may increase your risk of
bladder cancer, says a new study.
The new study is the first to suggest that
chlorine is harmful to humans when ingested or
absorbed through the skin, according to study
leader Cristina M. Villanueva of the Municipal
Institute of Medical Research in Barcelona and her
Chlorine itself is not harmful, but its
byproducts increase the risk of cancer.
Trihalomethanes are the most prevalent by-product,
and they can be absorbed into the body through the
skin or by inhalation. When THM is absorbed
through the skin or into the lungs, they hold
stronger carcinogenic properties because they
aren't detoxified through the liver, Villanueva
and her team found in their research.
Villanueva and her team surveyed 1,219
individuals with bladder cancer and 1,271 control
individuals without the disease, polling them
about their exposure to chlorinated water ,
including their bathing, swimming
and tap water drinking habits.
The researchers also looked at the THM levels in
the water systems of 123 municipalities.
People who live in households with more than 49
micrograms per liter of THM were at double the
risk of bladder cancer
versus households that have below 8
micrograms per liter of THM.
In industrialized countries, the common level is
50 micrograms per liter, the researchers note.
The researchers also found that use of swimming pools
increased the risk by 57 percent and that people
who drank chlorinated water held a 35 percent
greater risk. Taking long showers and bathing also
increases the risk in households that has water
with higher levels of THM.
In the United States, an estimated 67,160 new
cases of bladder cancer are expected to occur in
2007, and 13,750 deaths, according to statistics
from the American Cancer Society.
"If confirmed elsewhere, this observation has
significant public health implications in relation
to preventing exposure to these water
contaminants," the researchers said in their
The study was published in the January issue of
the American Journal of Epidemiology.
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