A major new study by a Canadian-led research team has found that almost all heart attacks that occur worldwide are due to preventable factors rather than genetics.

The researchers studied more than 29,000 people in 52 countries over a decade to see how factors like smoking, obesity and cholesterol levels increase the risk for heart disease.

Dr. Salim Yusuf, director of the Population Health Research Institute at Hamilton's McMaster University, found an abnormal ratio of "bad" to "good" cholesterol and smoking were responsible for two-thirds of the global risk of heart attack. These and seven other identifiable factors accounted for almost all preventable heart attacks around the world.

Dr. Salim Yusuf. (file photo)

"This [study] convincingly shows that 90 per cent of the global risk of heart disease is predictable," Yusuf, a professor of medicine at McMaster, told a news conference in Munich, where he presented the results at the European Society of Cardiology conference on Sunday.

"This is good news. It means we can do something about it."

Until now, smaller studies in the developed world suggested known risk factors accounted for about half of the risk of heart disease.

The new results suggest strategies to tackle heart disease, such as quitting smoking and losing weight, can be applied to men and women of all ages, regardless of race, age or geography, he said.

The other factors, in order of importance, were:

• Diabetes.
• High blood pressure.
• Abdominal obesity.
• Psychological stress, such as tension over a divorce.
• Inadequate daily consumption of fruits and vegetables.
• Lack of daily exercise.

Drinking three to five alcoholic drinks per week was a slightly protective factor, Yusuf and his colleagues found.

No. 1 killer

As part of the study, researchers compared about 15,000 people who had suffered their first heart attacks with someone of the same age, sex and location who had not had a heart attack.

Participants were followed over five years, until March 2003. Their cholesterol, diabetes and blood pressure were tested, and they were asked about their diet, exercise and smoking.

Together, heart disease and stroke are the No. 1 killers worldwide, according to the Heart and Stroke Foundation of Canada.

The study will be published in Sept. 11 issue of the medical journal The Lancet.

The study was funded by the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Ontario and 37 other funding sources, including several pharmaceutical companies that didn't attach any conditions to their funding.