Study finds cancercausing agent in cigarettes

WASHINGTON (Reuter) U.S. researchers said Wednesday they had found a
cancercausing chemical in the bodies of people exposed to secondhand
smoke the first hard evidence of how passive smoking can cause
cancer.

The compound, NNK, is found in the urine of people exposed to tobacco
smoke but not in those who have not breathed someone else's smoke,
Stephen Hecht and colleagues at the University of Minnesota Cancer
Center in Minneapolis found.

They told a meeting of the American Chemical Society in Las Vegas that
NNK is found only in tobacco smoke.

``This is the first time that a metabolite of a tobaccospecific lung
carcinogen has been found in the urine of nonsmokers exposed to
environmental tobacco smoke under field conditions,'' Hecht said in a
statement released by organizers of the meeting.

His team collected urine samples from nine hospital workers who were
caring for smoking patients in a Canadian veterans hospital. They
compared their samples to the urine of people who did not work around
smokers.

All the workers had signs of NNK in their urine, although at levels 70
times lower those found in smokers.

NNK has been found to cause adenocarcinoma, one type of cancer, in
animal studies. ``Adenocarcinoma is the type of lung cancer that's most
commonly found in nonsmokers who are exposed to environmental tobacco
smoke,'' Hecht said.

Doctors know that smoking causes cancer and heart disease and have
strong evidence that secondhand smoke does, too. But tobacco companies
argue that studies have not positively linked specific components of
tobacco smoke with cancercausing effects.