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Secondhand Smoke |
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Secondhand Smoke Increases Heart Risks
Accumulated data supports smoke-free environments,
experts say
The average nonsmoker walking into a smoke-filled
room might not think short-term exposure to cigarette
smoke will affect them.
But a new study suggests that even small amounts
of secondhand smoke can cause life-threatening
changes to a nonsmokers' circulatory system.
And while the immediate effects of this exposure
are reversed within a few hours, exposure to secondhand
smoke over longer periods of time can have devastating
consequences to the heart, including an increased
risk for heart attack, researchers warn.
"Secondhand smoke is even worse than we thought,"
said co-researcher Stanton A. Glantz, a professor
of medicine and longtime antismoking advocate
at the University of California, San Francisco.
"It increases the risk for an acute coronary
event like a heart attack or long-term development
of atherosclerosis," he added.
Chronic exposure to secondhand smoke is about
80 percent as deleterious to health as being a
pack-a-day smoker, Glantz said. "The cardiovascular
system is exquisitely sensitive to the toxins
of secondhand cigarette smoke. Most of the toxic
effects of secondhand smoke occur within five
minutes of exposure," he noted.
In their study, Glantz and his colleague Dr. Joaquin
Barnoya, an assistant adjunct professor of epidemiology
at UCSF, reviewed the existing medical literature
on the effects of secondhand smoke on the cardiovascular
system. They looked at 29 studies published since
1995 that compared the effects of secondhand smoke
with the effects of active smoking.
Their report appears in the May 24 issue of Circulation.
Glantz and Barnoya found there is sufficient evidence
that key aspects of cardiovascular function, including
clotting, the ability of blood vessels to change
size, arterial stiffness, atherosclerosis, oxidative
stress, inflammation, heart rate variability,
energy metabolism, and severity of heart attack
are all sensitive to toxins found in secondhand
smoke.
"The effects of even brief (minutes to hours)
passive smoking are often nearly as large (averaging
80 percent to 90 percent) as chronic active smoking,"
they wrote.
"It doesn't take much to cause big effects,"
Glantz said. "If you already have compromised
coronary circulation and go into a smoky environment,
there is a substantial increase in your risk of
an acute event."
Barnoya believes the findings belie what the tobacco
industry would have people believe. "The
arguments from the tobacco industry have been
that it is not likely that you can find such large
effects in passive smokers, given the dose they
get compared with the dose an active smoker gets,"
he explained.
But nonsmokers are more sensitive to the effect
of tobacco smoke than are active smokers, Barnoya
said. "In some cases, the effects are as
large or even larger than you see in an active
smoker."
The dangers of secondhand smoke are so great that
Barnoya believes everyone should avoid it. "We
should be fighting for smoke-free environments,"
he stressed.
Other experts not involved in the study are unanimous
in their agreement of the dangers of secondhand
smoke.
"Secondhand smoke disables and kills many
people by virtue of its cardiovascular effects
and also by virtue of its effects on the lung,"
said Dr. Norman H. Edelman, chief medical officer
for the American Lung Association.
Another expert sees secondhand smoke as an assault
on the health of nonsmokers. "How can any
society allow tobacco smoke to be imposed on innocent
bystanders?" asked Dr. David L. Katz, an
associate clinical professor of public health
and director of the Prevention Research Center
at Yale University School of Medicine.
"We have clear, convincing evidence that
those who smoke are swinging a big stick indeed
at the noses of those of us who don't," Katz
said. "While they should have autonomy over
their choices, they should not have autonomy over
ours. Smoking in public places does not stop where
my nose begins and therefore, it should be banned.
Not just by some states, but by all. This study
will, I hope, help cultivate the political will
to see that job is done sooner rather than later."
Requests for a response from cigarette maker Philip
Morris Inc., were not answered at press time.
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