November 18, 2002
IL (AHA) – Children with one parent
who smoked in their presence had up to 50 percent higher levels
of a biological marker of oxidative stress in their blood,
Austrian researchers reported at American Heart Association's
Scientific Sessions 2002.
In another study
on the effects of second-hand smoke, Japanese researchers sought
to determine if short-term exposure to environmental tobacco
smoke affected free-radical production in young, healthy
evidence shows that second-hand smoke breaks down the
antioxidant defenses, which is associated with impairment of the
endothelial-dependent function of arterial walls. Endothelial
dysfunction is an early feature of atherosclerosis, the disease
process that underlies heart disease and stroke, and is an
important marker of vascular damage.
which are unstable molecules produced during a process called
oxidation, can damage cells in the body. This damage is often
called oxidative stress. It is significantly higher in children
exposed to second-hand smoke.
oxidation injury, the Austrian researchers examined levels of a
biological compound called 8-epi-PGF2alpha in the blood and
urine of 158 children (71 boys, 87 girls) ages 3 to 15. The
compound is formed when free radicals attack arachidonic acid, a
chemical whose normal function includes blood vessel dilation,
blood clot prevention and inflammation reaction.
"It is a very
potent blood vessel constrictor and may help create blood vessel
spasm and set the stage for blood clot formation," says senior
researcher Helmut F. Sinzinger, M.D., of the University of
Vienna in Austria.
grouped according to the smoking levels of their parents,
whether both parents were smoking at home, and according to the
number of cigarettes smoked each day. Researchers compared
results to those from a nonsmoking control group.
Blood and urinary
8-epi-PGF2alpha levels were elevated if children were exposed to
second-hand smoke by smoking parents. "Even if exposed to the
second-hand smoke from less than 20 cigarettes a day by one
smoking parent, levels were elevated in plasma by 35 to 50
percent and in urine by 20 to 30 percent," Sinzinger says.
number of cigarettes smoked in the home correlated to higher
levels of 8-epi-PGF2alpha, regardless of the child's age or
gender. Researchers found that if parents were together smoking
more than 40 cigarettes a day, blood 8-epi-PGF2alpha was as much
as 130 percent higher than that of the control group and urinary
8-epi-PGF2alpha was about 65 percent higher than in the control
group. Further, smoking by the mother had a significantly more
that mothers may have closer contact with their children at
home," Sinzinger says. It's too early to speculate on measures
other than recommending parents not smoke when their children
"It is well known
that atherosclerotic lesions on vascular tissue are strongly
correlated to risk factors that include cigarette smoking,"
Sinzinger says. "Considering that in the United States and
Western Europe nearly half of all children are exposed to
second-hand smoke in some way, these findings could be of great
importance. Later vascular disease might be triggered early in
childhood by exposure to second-hand smoke."
In the Japanese
study, researchers recruited 12 non-smoking men, average age 30,
with no history of cardiovascular disease, high blood pressure
or diabetes. They tested their levels of 8-epi-PGF2alpha and
used ultrasound to measure endothelial function in subjects'
brachial artery before and after a 30-minute exposure to
environmental tobacco smoke. Flow-mediated dilation (FMD) is an
inexpensive and safe way to evaluate endothelial function. It
measures changes in the amount of blood flow through a
particular blood vessel.
is the inner lining of blood vessels. This thin layer of cells
helps vessels expand and contract in response to different
amounts of blood flow. If these cells are damaged, the blood
vessels will be "stiff" and less able to handle the body's
changing blood flow needs.
After exposure to
tobacco smoke, the men’s blood levels of 8-epi-PGF2alpha
significantly increased from an average of 20 picograms per
milliliter (pg/mL) to 36 pg/mL. Their FMD decreased from 7.8
percent to 3.9 percent.
may add relevance to the idea that everyone should be protected
from even short-term exposure to second-hand smoke," says lead
researcher Toru Kato, M.D., Ph.D., of the division of cardiology
at Saitama Medical Center, Saitama Medical School in Japan.
Co-authors of the
Japanese study are Shunichi Sato, M.D.; Toshihiko Nishioka;
Mikio Yuhara; Yoshiro Inoue; Hiroyuki Ito; Yoshiaki Maruyama;
Shugo Tanaka; and Nobuo Yoshimoto, M.D., Ph.D.
Co-authors of the
Austrian study are Anthony Oguogho, M.D., and Heidemarie Pilz,