Passive smoking causes lasting damage to children’s arteries, prematurely ageing their blood vessels by more than three years, say researchers.
The damage – thickening of blood vessel walls – increases the risk of heart attacks and strokes in later life, they say in the European Heart Journal.
In their study of more than 2,000 children aged three to 18, the harm occurred if both parents smoked.
Experts say there is no “safe” level of exposure to second-hand smoke.
“This study goes a step further and shows it [passive smoking] can cause potentially irreversible damage to children’s arteries increasing their risk of heart problems in later life”
The research, carried out in Finland and Australia, appears to reveal the physical effects of growing up in a smoke-filled home – although it is impossible to rule out other potentially contributory factors entirely.