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Carcinogens From Parents' Tobacco Smoke Found In Their Babies' Urine
ScienceDaily (May 12, 2006) — PHILADELPHIA -- When mom or dad puffs on a
cigarette, their infants may inhale the resulting second-hand smoke. Now,
scientists have detected cancer-causing chemicals associated with tobacco
smoke in the urine of nearly half the babies of smoking parents. 
"The take home message is, 'Don't smoke around your kids,'" said Stephen S.
Hecht, Ph.D., professor and Wallin Chair of Cancer Prevention at The Cancer
Center at the University of Minnesota. 
According to a study of 144 infants, published in the May issue of Cancer
Epidemiology, Biomarkers & Prevention, Hecht and his colleagues found
detectable levels of NNAL* in urine from 47 percent of babies exposed to
environmental tobacco carcinogens from cigarette smoking family members.
NNAL is a cancer-causing chemical produced in the human body as it processes
NNK**, a carcinogenic chemical specific to tobacco. 
"The level of NNAL detected in the urine of these infants was higher than in
most other field studies of environmental tobacco smoke in children and
adults," Hecht said. 
"NNAL is an accepted biomarker for uptake of the tobacco-specific carcinogen
NNK. You don't find NNAL in urine except in people who are exposed to
tobacco smoke, whether they are adults, children, or infants." 
A previous study by Hecht and his colleagues indicated that the first urine
from newborns whose mothers smoked during pregnancy contained as much as
one-third more NNAL compared to the babies in the current study. The newborn
infants, however, took in the carcinogen directly from their mothers through
their placentas rather than by breathing second-hand smoke in the air in
their family homes and cars. 
In the current study, when babies had detectable levels of NNAL, Hecht said
that family members smoked an average of 76 cigarettes per week, in their
home or car while the babies were present. In children of smokers whose
babies had undetectable levels of NNAL in their urine, the average number of
cigarettes smoked by family members was reported at 27 per week. 
"With more sensitive analytical equipment, the NNAL from urine of babies in
lower frequency cigarette smoking households would most likely be detectable
" Hecht said. 
While studies have not determined how the long term risk of exposure to
cancer-causing tobacco smoke affects the genetics of babies during their
early years when they are growing rapidly, Hecht said that this study
demonstrated substantial uptake of NNK and its metabolite NNAL in infants
exposed to environmental tobacco smoke. 
"These findings support the concept that persistent exposure to
environmental tobacco smoke in childhood could be related to cancer later in
life," he said.
Hecht conducted his study in collaboration with Steven G. Carmella, Ky-Ahn
Le, Sharon E. Murphy, Angela J. Boettcher, Chap Le, Joseph Koopmeiners,
Larry An, and Deborah J. Hennrikus from the Transdisciplinary Tobacco Use
Research Center and The Cancer Center, University of Minnesota. 
* 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol 
** 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone

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