(KRT) - Mr. Rao always chalked up his high cholesterol and blood pressure to bad luck, figuring a family history of heart troubles set him up for coronary artery disease. The 48-year-old never suspected his ethnicity could be to blame.

But now researchers have determined that those of Indian and Pakistani descent have the highest rates of heart disease in the world, despite coming from a culture that shuns smoking, encourages a vegetarian diet and lacks many of the other classic risk factors for the disease.

About 25 percent of all heart attacks among men of Indian descent occur while they are younger than 40, unheard of in any other population, according to researchers. Death rates from the disease are up to three times higher among Indians than those of European or East-Asian origin.

Such findings, borne out most recently by a new report, surprise many Indo-Americans - and just as many doctors. Research carried out in the United Kingdom years ago began to suggest a genetic link, but there has not been a push for early screening in the Indo-American community here, and relatively few education campaigns.

"Most physicians trained in the U.S. are not aware their Asian-Indian patients are at risk," said Dr. Susan Ivey, an assistant researcher at the University of California-Berkeley Center for Family and Community Health, which spearheaded the new study.

And this lack of awareness, researchers worry, may be deadly.

"Just being of Asian-Indian descent places you at higher risk for heart disease than having high cholesterol and being a smoker," said Dr. H. Robert Superko, director of research at the Berkeley HeartLab.

Superko launched a separate study, the National Asian Indian Heart Disease Program, several years ago and discovered one gene is responsible for part of the increased risk in heart disease rates. A metabolic disorder common in Indians likely also plays a role, as does having high levels of a dangerous type of cholesterol. Lifestyle, such as diet and lack of exercise, is also to blame.

The problem is coming into sharpest focus in places such as California’s Bay Area, where Indians are the fastest growing of all Asian groups. But there are 1.6 million Indians sprinkled all over the United States who are also at risk. Because the population is scattered, researchers say it is difficult to study the problem fully or raise awareness among doctors and within communities.

The elevated risk of heart disease often catches many Indians off guard. Generally, their overall cholesterol levels have been normal. High blood pressure isn’t prevalent in the community. Smoking rates are low. And about half are vegetarians.

Knowing that doing many of the right things to prevent the disease still might not be enough, "It does make you afraid," said Mr. Rao, a Yuba City sandwich shop owner who immigrated from India nearly three decades ago. His father has been battling heart problems for years.

"A lot of people, they just feel they look healthy, they feel healthy," and so they don’t get tested for heart disease, Mr. Rao said. "By the time some of them find out they have it, they’re either in an ambulance or a hospital bed."

As lifestyles change in India, heart disease is hitting epidemic proportions there - and also among Indo-Americans - with more than 10 percent of urban Indians now suffering from the disease. Over the past three decades, coronary artery disease rates have declined by half in many developed countries, but have more than doubled in India, according to the Coronary Artery Disease among Asian Indians Research Foundation. Rates are significantly higher in urban regions of India than in rural ones.

This helps dispel the theory that a Western lifestyle is entirely to blame for the problem among immigrants, some scientists believe. Dining on greasy fast food and adopting a couch-potato lifestyle can certainly make the situation worse, they said. But other factors clearly are at play.

"Genetics load the gun. Environment pulls the trigger," said Dr. Enas A. Enas, director of the research foundation.

That is all the more reason why Indo-Americans need to be aggressive about preventing heart disease. Parents should be sure to start their children on health diets and exercise programs when they’re as young as age 2, Enas said.

"If you have a loaded gun and you don’t pull the trigger, no harm is done."

Viren Venkat, 66, knows first-hand the importance of a healthy lifestyle. The Sunnyvale resident experienced his first heart attack when he was only 44. His oldest brother, Surendra, had one at 48. Another brother, Narendra, had one at 47.

They were all busy business executives, and none of them got much exercise, he conceded, but they were still surprised to suffer heart problems at such an early age.

At the time of Venkat’s first attack, he lived in Bombay and worked as a record executive in India. His staff included a gardener, a chauffeur and a cook. Venkat didn’t even have to carry his briefcase to his car in the morning.

Like many Indians and Indo-Americans, he ate heavier food cooked in ghee, or clarified butter. Doctors recommend that foods be cooked in olive oil instead.

Enas is convinced that high heart disease rates are partially attributable to what he calls an "influence of affluence," which could help explain the higher rates in urban India versus rural regions. Research into this theory is still ongoing, but Enas points to the highly automated lifestyle that is enjoyed in urban areas.

"Indians are Silicon Valley high-tech execs. What do they do? They do not exercise. How do they go to work? By car," Enas said.

The Berkeley researchers believe that the children and grandchildren of Indian immigrants could be at the highest risk for heart problems, given their lifestyle as children is much more inactive than their parents’ tended be. The scientists, who looked at more than 300 Indo-Americans living in Yuba City and Alameda and Contra Costa counties, anticipate the phenomena won’t be visible, however, for a few more years.

"We haven’t hit the big wave of second- and third-generation" Indo-Americans, Ivey said. "Indians are more at risk when they’re put in a Western environment."