Researchers from Argentina presented their data at the European Society of Cardiology Congress in Birmingham yesterday.
They had looked at 2,000 people who said that they had never smoked and after collecting data on the smoking habits of their spouses and children assessed the relative risks of having a heart attack.
Those who lived with a spouse smoking more than 20 cigarettes a day had nearly two and a half times the risk of those who were married to a non- smoker. People who lived with a lighter smoker or had children who smoked still saw their risk go up by 50 per cent. When high-risk factors, such as high blood pressure, were present passive smoking intensified the danger.
"Passive smoking at home appears to be associated with the risk of acute myocardial infarction [heart attack] and there is a significant increase in relative risk with the amount exposed daily," the researchers said.
Passive smoking has been a contentious issue. In 1992 the United States Environment Protection Agency decided environmental tobacco smoke was a class A carcinogen, estimating that it caused 3,000 deaths a year.
Many public areas such as restaurants, aircraft and railways have banned smoking. High-profile cases such as that of the entertainer Roy Castle whose fatal lung cancer was said to have been caused by passive smoking and Veronica Bland who won pounds 15,000 compensation after claiming she had contracted chronic bronchitis at work, have encouraged bans.
However, last May the European Working Group on Environmental Tobacco Smoke analysed 48 studies and concluded that passive smoking did not cause cancer.
A spokeswoman for the anti-smoking pressure group ASH said: "There's been a lot of research which shows that people whose spouses smoke are at an increased risk of health damage. We do not want to dictate to people about what goes on in their homes but it shows the urgent need for legislation on smoking in public places."
But Martin Ball, of Forest, which supports the right to smoke, said: "The claims of exposure to environmental tobacco smoke have been demolished over the years, shown to be bogus and based on rotten science."
Football players have the highest risk of sudden death while playing sport, and even table tennis and skittles can pose a threat according to new research. But doctors at the European Society of Cardiology Congress insisted yesterday that the benefits of keeping fit far outweighed the risk.
Nearly four out of five sudden deaths in sport are due to cardiovascular disease, and in the over-35s the majority are due to coronary heart disease. In Britain around one in 50,000 active athletes die every year.
Doctors looked at the sudden deaths of more than 2,000 people in German sports clubs from 1981-1994. Football was most dangerous, claiming 628 lives. Tennis claimed 151, cycling 124 - just ahead of gymnastics; table tennis 86, skittles 73, horse riding 55 and canoeing 45.
But Dr Willem Mosterd, a Dutch professor of clinical sports medicine, said the numbers of deaths from sport were "very low" and the benefits of regular exercise had been proved: "Physical inactivity and low fitness contributes substantially to major chronic diseases. The most convincing group concerns coronary heart disease. People who are regularly active have about half the risk of those who are sedentary."Reuse content