The Population Health Research Institute at McMaster University and Hamilton Health Sciences in Ontario, Canada, coordinated the Interheart study, which included participants from 52 countries and all inhabited continents of the world. Dr. Salim Yusuf, a professor of medicine at the Michael G. DeGroote School of Medicine at McMaster University and director of the health research institute, presented the study at the European Society of Cardiology (ESC) conference in Munich, Germany.

The study found that in addition to cigarette smoking, an abnormal ratio of blood lipids (Apolipoprotein B/Apolipoprotein A-1) is associated with heart attacks. Together, these two factors can predict two-thirds of the global risk.

Additional risk factors are high blood pressure, diabetes, abdominal obesity, stress, a lack of daily consumption of fruits and vegetables and a lack of daily exercise.

Regular consumption of small amounts of alcohol was found to be modestly protective.

Worldwide, these nine factors collectively predict more than 90 per cent of the risk of a heart attack.

The participants in the Interheart study consisted of 15,152 individuals with their first heart attack and 14,820 others who did not have heart disease but who were of the same age, gender, and from the same city as those who did. They included 7,000 people of European extraction; 2,000 from Latin America; 6,000 Chinese; 4,000 South Asians; 2,000 from other parts of Asia; 3,500 Arabs; and 1,400 Africans.

This study is the first substantial examination of whether risk factors for heart attack have a similar or different impact among all major ethnic groups worldwide.

Conventional wisdom previously suggested that only 50 percent of heart attacks could be anticipated, Yusuf said, but the Interheart findings show that the overwhelming majority of heart-attack risk cases can be identified in advance.

"These risk factors appear to predict the majority of the risk in virtually every region, every ethnic group, in men and women and in the old and the young," said Yusuf. "This suggests that the message of preventing cardiovascular disease can be quite simple and, generally, similar across the world, after taking into account economic and cultural differences.

"Since these risk factors may all be modified, this is remarkable and will change the way we look at heart attack prevention. It means we should be able to prevent the majority of premature heart attacks in the world."

There is a growing epidemic of cardiovascular disease worldwide, with more than 15 million deaths from heart attacks in 1998 alone, according to Dr. Alan Bernstein, president of the Canadian Institutes of Health Research.

"This is a landmark study," Bernstein says. "It suggests that a combination of lifestyle changes -- including stopping smoking, eating a healthier diet, and exercising -- could lead to an 80 percent reduction in the risk of heart attacks."

The Interheart study is scheduled for publication in The Lancet on September 11 but already is available on the publication's website.