SYDNEY: Children exposed to their parents' cigarette smoke are at greater risk of suffering serious cardiovascular health problems later in life, a study showed on Wednesday.

The Menzies Research Institute in Tasmania collected data from a Finnish and Australian study following children first examined 20 years ago who are now aged in their mid-30s.

It found that those exposed to passive smoke as youngsters have less elasticity in their arteries, an indicator of poor cardiovascular health.

Study author and Menzies Research fellow Seana Gall said while it has been previously known that passive smoke was harmful, this was the world's first examination on the long-term effects on blood vessel health.

“We looked at blood vessel elasticity by measuring the ability of an artery in the arm to expand and contract,” she said.

“We found that people who had been exposed to parental smoking when they were children had less elastic arteries, an early indicator of poor cardiovascular health.” Gall added that it was not explained by the participants' own smoking habits.

“The effect was seen up to 27 years later, suggesting a long-term and irreversible effect of passive smoking in childhood on the health of arteries,” she said.

“The chemicals in cigarette smoke interact with the lining of the blood vessels and that seems to be causing an inability of them to expand and contract properly.” The World Health Organisation estimates that about 40 per cent of the world's children are regularly exposed to second-hand smoke at home, with 600,000 deaths annually caused by passive smoking.

“The highest prevalence of smoking is still seen in those age groups that correspond with people first becoming parents, so that's still a concern and we'd want to get the prevalence down in those groups particularly,” said Gall.