South Asians make up 1/4 of the world's population. Researchers have known that they tend to have heart attacks at earlier ages than people from other parts of the world. Now they have identified the reasons why. VOA's David McAlary explains from Washington.

Food vendor in Srinagar

A new study in the Journal of the American Medical Association confirms that people from India and other South Asian countries do have heart attacks earlier. Physician Salim Yusuf of McMaster University and Hamilton Health Sciences in Ontario, Canada is one of the researchers. "The age of 53 or 54 is the mean [average] age in South Asians for heart attack, whereas it is about 58 or 59 in other parts of the world," he said.

This disparity has raised the question of whether South Asians have a special susceptibility for heart attacks not explained by traditional risk factors, such as smoking, lack of exercise, a poor diet, and high cholesterol.

To determine the reason, Yusuf and his colleagues looked at data on more than 27,000 people from South Asia and other parts of the world. Eight years after the first volunteer was recruited, they have answers. "The reason why South Asians get heart disease at an earlier age is because they have a higher proportion of people with bad cholesterol and less good cholesterol."

Yusuf says there is probably an unexplained biological reason for this, although poor diet appears to play a role. He points out that in dishes like curries, vegetables are often cooked so long, they lose health benefits, and that these habits follow South Asians wherever they migrate.

But higher cholesterol is not the only risk factor setting South Asians apart. The study says they also have more diabetes, high blood pressure, tobacco use, depression, and stress at home.

Yusuf says migrating to North America adds to the problem. "I think South Asian immigrants who have come to North America are at even greater risk of heart disease compared to those living in their home countries and the reason for this is that they are even more urbanized," he said.

Dr. Yusuf's advice is to eat healthy foods, exercise, avoid tobacco, and get regular medical examinations. "All these are good general advice that we give anybody, but in South Asians they matter even more," he said.