Bans on smoking in public places have had a bigger impact on preventing heart attacks than ever expected, data shows.

数据显示，禁止在公共场所吸烟对防止心脏病有未曾想到的影响。

Passive smoke raises heart risk

Smoking bans cut the number of heart attacks in Europe and North America by up to a third, two studies report.

This "heart gain" is far greater than both originally anticipated（预先考虑） and the 10% figure recently quoted by England's Department of Health.

The studies appear in two leading journals - Circulation and the Journal of the American College of Cardiology（心脏学）.

Heart attacks in the UK alone affect an estimated 275,000 people and kill 146,000 each year.

Big impact

Earlier this month it was announced that heart attack rates fell by about 10% in England in the year after the ban on smoking in public places was introduced in July 2007 - which is more than originally anticipated.

But the latest work, based on the results of numerous different studies collectively involving millions of people, indicated that smoking bans have reduced heart attack rates by as much as 26% per year.

Second-hand¹ smoke is thought to increase the chances of a heart attack by making the blood more prone² to clotting³（凝块）, reducing levels of beneficial "good" cholesterol⁴（胆固醇）, and raising the risk of dangerous heart rhythms.

Dr James Lightwood, of the University of California at San Francisco, led the Circulation study that pooled together 13 separate analyses.

His team found that heart attack rates across Europe and North America started to drop immediately following implementation⁵ of anti-smoking laws, reaching 17% after one year, then continuing to decline over time, with a 36% drop three years after enacting⁶ the restrictions⁷.

Dr Lightwood said: "While we obviously won't bring heart attack rates to zero, these findings give us evidence that in the short-to-medium-term, smoking bans will prevent a lot of heart attacks.

"This study adds to the already strong evidence that second-hand smoke causes heart attacks, and that passing 100% smoke-free laws in all workplaces and public places is something we can do to protect the public."

Ellen Mason, of the British Heart Foundation, said: "These studies add to the growing evidence that a ban on smoking in public places seems to have a positive impact on heart attack rates, which is clearly good news for our nation's heart health.

"The statistics also show how quickly the benefits can be felt after a smoking ban is implemented⁸ and indicate how dangerous second-hand smoke can be to the heart.

"If you are a smoker⁹, the single biggest thing you can do to avoid a heart attack is to give up, which could also protect the heart health of friends and family."

Latest figures show at least 70,000 lives have been saved by NHS Stop Smoking Services in the 10 years since they were established in England.