As the prevalence of heart disease increases worldwide, researchers have found that people in developing countries suffer from it for the same reasons people in industrial nations do. Smoking, fatty diets, and stress top the list of heart attack risks.

Heart disease is the largest cause of death worldwide. Eighty-percent of the cases occur in developing nations, but most of what we know about the causes comes from studies among people in Western countries, mainly middle aged white men.

Now a new study of 30,000 men and women in 52 nations on every inhabited continent shows that the rest of the world is no different.

"The factors that cause heart attacks are the same," says Sonia Anand, [physician] at McMaster University in Hamilton, Ontario, Canada, where the findings were analyzed. "What we found is nine simply measured risk factors predict the majority of heart attacks around the world."

The researchers say these risk factors account for 90 percent of heart attacks internationally and are consistent across all regions and ethnic groups, young or old, male or female.

Two of them stand out, smoking and fatty diets. Together they account for two-thirds of heart attack risk.

"The two most important things that we can do as a society, one is to prevent smoking or [encourage] smokers to stop, and the second is that we can see the adverse consequences of weight gain or obesity," says Dr. Anand.

Surprisingly, the international study found the third most-important cause of heart disease is emotional stress. Dr. Anand says it is responsible for one-fifth of heart attacks and is independent of bad life style habits like smoking and poor diet.

"Some people think, well, you are stressed out so you are going to eat more or smoke more, and that is why you get your heart attack," she notes. "What we are seeing is there is an independent relationship between stress and having a heart attack. That is an important area for us to explore because prior studies weren't large enough or precise enough to really show this relationship."

Other but lesser risk factors for heart attack are high blood pressure and diabetes. Genetic inheritance seems to account for a tiny portion of this disease.

Protecting against heart disease are consumption of fruits and vegetables, moderate amounts of alcohol, and regular physical exercise.

While industrial countries have enjoyed a decline in heart disease in the past few decades, death rates have increased dramatically in low and middle income nations. Dr. Anand says the findings can help governments determine how to counter the trend.

"There is a prediction that countries like India and China will experience an epidemic of heart disease by the year 2020," she adds. "These studies allows those countries now to begin to put in place prevention policies to try and curb the epidemic."

The study results appear in the medical journal Lancet.