Public smoking ban 'cuts heart attacks'

By JEREMY LAURANCE

People at risk of heart disease should avoid buildings where smoking is permitted, says a United States federal public health agency, in the starkest warning yet about the dangers of tobacco.

Even 30 minutes of exposure to other people's smoke, while eating in a restaurant or sitting in an office, might be enough to trigger a fatal heart attack for those at risk, the Centres for Disease Control and Prevention in Atlanta said this week.

It is the first time the US Government agency in charge of protecting the nation's health has told non-smokers that they should not enter buildings or enclosed spaces where other people are smoking.

The warning follows growing evidence that, as well as the long-term effects of smoking in causing heart disease and cancer, toxins in tobacco smoke also have rapid short-term effects in causing the blood to clot.

Britain's Department of Health said this week that it had consistently said smoke-free polices were the ideal and had drawn attention in leaflets to the immediate effects of second-hand smoke on the heart.

A spokeswoman said: "People with heart conditions do need to take extra precautions."

The stronger American warning is in an article in the British Medical Journal, accompanying a study of Helena, a small town in Montana, which banned smoking in public in June 2002, only to have the ban rescinded six months later by opponents of the law.

During the ban, when smoking was outlawed in offices, factories, restaurants, bars and all public enclosed spaces, heart attack admissions to the local hospital fell by 40 per cent.

After the ban was lifted, the heart attack rate increased to its former level.

The study was published online this month at www.bmj.com, but this week it has appeared in the paper edition of the journal with, for the first time, the associated comments by the Centres for Disease Control.

Even eating in a smoky restaurant could cause a heart attack, said the authors, Terry Pechacek and Stephen Babb of the centres' Office on Smoking and Health. They said: "As unlikely as this sounds, a growing body of scientific data suggests that this is possible."

Scientists have been puzzled by the disproportionate risks associated with passive smoking.

A non-smoker who lives with a person who smokes 20 cigarettes a day has one-third of the risk of the partner, even though they are exposed to 1 per cent of the smoke.

Laboratory evidence suggests that this is because toxins in tobacco smoke peak at low levels of exposure, increasing the tendency of blood platelets to stick together and inflaming the arteries, increasing the risk of thrombosis - a blood clot that can trigger a heart attack.

The result is that the risk of heart problems increases rapidly for people who smoke one to five cigarettes a day, but then rises more slowly as smoking increases to 20 cigarettes a day.

- INDEPENDENT