Passive smoking heart risk worse than thought

LONDON - Passive smoking may be much more dangerous than scientists had thought, researchers say in a new study that is likely to boost demand for a ban on smoking in public places.

Earlier research into the effects of second-hand smoke had focused on non-smokers living with smokers. Scientists in Britain studied exposure to passive smoke by measuring a breakdown product of tobacco smoke called cotinine in the blood of non-smokers.

They found high concentrations of blood cotinine levels were associated with a 50 to 60 per cent higher risk of coronary heart disease.

Previous studies had estimated the raised risk of heart disease from passive smoking in non-smokers at 25 to 30 per cent.

"We've studied only people who are non-smokers and seen how their levels of cotinine, which reflect the amount of passive smoking they have been exposed to, and then related it to their subsequent heart disease risk," said Professor Peter Whincup, of St George's Hospital Medical School in London.

"People who were non-smokers but had relatively high levels of cotinine had a heart disease risk of about 50 per cent higher than those people who were exposed to low levels."

Professor Whincup, who reported the findings on BMJ Online First, said the research provided further evidence that passive smoking had adverse effects that might have been underestimated in the past. Supporters of a ban on smoking in the workplace, bars and restaurants described the findings as further evidence for new smoking legislation.

"The need for a ban on smoking in public places in the UK has never been better illustrated than by this potentially pivotal study. We have known for some time that passive smoking was strongly associated with increased risk of coronary heart disease but this study strengthens the evidence considerably," said Dr Tim Bowker of the British Heart Foundation, which partly funded the research.

"The evidence is now compelling. The Government should not delay any further in introducing legislation to protect non-smokers from this unnecessary risk."

Ireland recently became the first country to ban smoking in public places. New York and parts of Australia have taken similar measures.

- REUTERS