Passive smoking may be much more dangerous than scientists had thought, British researchers said today in a new study that is likely to boost demand for a ban on smoking in public places.
Scientists in Britain studied exposure to passive smoke by measuring a breakdown product of tobacco smoke called cotinine in the blood of non-smokers.
Previous research has found that passive smoking is linked with a 25 to 30 per cent increased risk of coronary heart disease.
But the latest study found that non-smokers faced a 50 to 60 per cent increased risk of falling victim to the disease.
The researchers noted that most studies on passive smoking examined the risks of living with someone who smoked.
They said while this was important it did not take into account the additional exposure at work and other places like pubs and restaurants.
The researchers took blood samples to measure cotinine, concluding that higher concentrations in the blood of non-smokers were associated with a 50 to 60 per cent greater risk of heart disease.