A new study has shown that children exposed to secondhand smoke have conditions that put them at a higher risk of developing heart disease.
Researchers at the University of Turku, in Finland, found that 13-year-olds who had had frequent exposure to tobacco smoke exhibited thicker artery walls, higher levels of cholesterol, and other blood vessel problems.
Executive Director of Quit, Fiona Sharkie, said the findings reinforce the message that people should not be smoking around kids.
"The evidence on this issue just keeps mounting. We already know that second hand smoke is associated with a higher incidence of many health problems in children, including asthma attacks, meningococcal disease, pneumonia and SIDS."
"The likelihood that children are being put at a greater risk of heart disease as well should make smokers think twice about lighting up around kids."
The latest Cancer Council Victoria research suggests 4 out of 10 smokers still smoke around children.
Ms Sharkie said new legislation in place banning people from smoking in cars with children is an excellent start, but smokers needed to take responsibility for protecting children in other places.
"This study reinforces that no amount of exposure to tobacco smoke is okay when it comes to children," Ms Sharkie said.
Heart Foundation Victoria CEO Kathy Bell said the study further highlights the dangers of secondhand smoke for children.
"Heart disease isn't something that only affects older people - as we can see from this study the risk factors are mounting in teenagers as young as 13. To give kids the best chance later in life, adults need to do all they can to protect them from any cigarette smoke now."
Although it's been known that secondhand smoke has negative effects on arteries in adults, this is the first time it's been shown to happen in children.
The study was of 494 13-year-olds in Finland, who had been exposed to second-hand smoke since they were 8.