By Kathleen Fackelmann, USA TODAY

About one in five American men ages 30 to 34 may have an advanced case of clogged arteries that creates a high risk of a heart attack in the next 10 to 15 years, says a report out today.

For the most part, those young men have no symptoms of the fatty plaque insidiously building up on the inner walls of their arteries, says Henry C. McGill Jr., lead author of the report in Circulation: Journal of the American Heart Association .

"The tragic part is that they are young men at the peak of their careers, some of whom will drop dead," McGill says.

About half those who die suddenly of heart disease drop dead without any warning sign like chest pain, says the American Heart Association (AHA).

Yet McGill and other experts say that grim outcome doesn't have to happen. In many cases, simple lifestyle changes, including a low-fat diet and regular exercise, can help lower the risk of heart disease, they say.

McGill, a researcher at the Southwest Foundation for Biomedical Research in San Antonio, and his colleagues studied 760 teens and adults ages 15 to 34 who had died as a result of an accident, a homicide or a suicide.

During the autopsy, the researchers took blood and measured the thickness of the plaque clogging the left artery supplying the heart with blood.

Based on autopsy results, researchers project that up to 2% of males ages 15 to 19 have severe atherosclerosis, in which 40% or more of the artery is clogged with plaque.

Most of those teens won't suffer a heart attack tomorrow, McGill says. Yet they are well on their way to an early heart attack, he says.

The study's findings highlight a gender difference. The team found no cases of advanced plaque in females ages 15 to 19. And just 8% of women ages 30 to 34 had severe plaque.

McGill says women appear relatively protected from heart disease until after age 55.

The study also shows that factors known to put older people at risk of heart disease also put younger folks in jeopardy.

The San Antonio team found that:

Teens and young adults with high levels of the bad cholesterol ?low density lipoprotein (LDL) cholesterol ?are 2 1/2 times more likely to have severe blockage than those without that risk.

Overweight teens and young adults also are 2 1/2 times more likely to have advanced plaque than their trim peers.

The results of the study probably provide a snapshot of the general public, but further studies must prove that assumption, AHA spokesman James Moller says.

Still, the study adds to evidence that heart disease isn't just a malady of old age, Moller says. "Heart disease has its antecedents in childhood."

(From US TODAY HEALTH)