— Exposure to second-hand smoke in childhood causes
irreversible damage to children's arteries — increasing their risk
of heart attacks or strokes when they grow up, according to a large
international study published on Wednesday.
The research, which lends weight to campaigns for
smoking to be banned in private cars and homes, found passive
smoking leads to a thickening of children's artery walls, adding
some 3.3 years to the age of blood vessels by adulthood.
"Exposure to passive smoke in childhood causes direct and
irreversible damage to the structure of the arteries," said Seana
Gall, a researcher in cardiovascular epidemiology who led the study
at the University of Tasmania.
She said parents, or even those thinking about becoming parents,
should quit smoking — both to aid their own health and protect the
future health of their children.
Smoking causes lung cancer, which is often fatal, and is the world's
biggest cause of premature death from chronic conditions like heart
disease, stroke and high blood pressure.
On top of the 6 million people a year killed by their own smoking,
the World Health Organization (WHO) says another 600,000 die a year
as a result of exposure to other peoples' smoke — so-called
second-hand or passive smoking.
Of the more than 4,000 chemicals in tobacco smoke, at least 250 are
known to be harmful and more than 50 are known to cause cancer, the
WHO says — and creating 100 percent smoke-free environments is the
only way to protect people fully.
About 40 percent of all children are regularly exposed to
second-hand smoke at home, and almost a third of the deaths
attributable to second-hand smoke are in children.
This latest study, published in the European Heart Journal, was the
first to follow children through to adulthood to look at links
between exposure to parents' smoking and thickness of the innermost
two layers of the arterial wall, known as carotid intima-media
Researchers from Finland and Australia looked at data from 2,401
people in Finland 1,375 people in Australia who were asked about
their parents' smoking habits. The scientists used ultrasound to
measure the thickness of the children's artery walls once they had
The results showed that carotid IMT in adulthood was 0.015
millimeters thicker in those exposed to both parents smoking than in
those whose parents did not smoke.
Gall said that while this was a "modest" increase, it was
nonetheless an important extra and irreversible risk for suffering
heart attacks or strokes later in life.
Since children of parents who smoke are also more likely to grow up
to be smokers themselves, and more likely to be overweight, their
heart health risks are often already raised, she said, and the
second-hand smoke adds yet more risk.
The researchers said the findings showed reducing children's
exposure to smoke is a public health priority.
"Legislation can reduce passive smoke exposure, with restriction of
smoking in public places reducing hospitalizations for
cardiovascular and respiratory disease," they wrote, adding that
banning smoking in cars with children in them would also have a
significant positive effect.
The United States, Australia and Canada have already banned smoking
in cars carrying children, and Britain said last month that it too
would be introducing a ban soon.