DEAR DR. ROACH: I’m always saddened when a young person dies of an old person’s calling. I read about an actor dying of a heart attack at age 57. Apparently, he was athletic and in otherwise good health. Why do healthy young people suffer from unexpected heart attacks?

— A.C.G.

ANSWER: A heart attack is very rare under the age of 30 — in the order of about 2 men per 100,000 per year. But this number continues to increase throughout lifetime. (Women also get heart disease but at a lower rate than men do at any given age. Roughly speaking, a woman’s risk for a heart attack is about the same as a man who is 10-15 years younger.)

Heart attacks that happen in very young men and women often have to do with anomalous coronary arteries; syndromes like familial hypercholesterolemia; or drugs, especially cocaine. (A famous basketball player died suddenly due to not having a left coronary artery.)

I’m glad to hear you say that 57 is young, but the rate of a heart attack at 57 is about 8 men per 1,000 each year. So, by no means is it a rare event in this age group. At this age, it’s most likely due to atherosclerosis — cholesterol and calcium plaques in the blood vessels of the heart, which can rupture and cause a clot that prevents blood flow to part of the heart. Unless the blood flow is rapidly restored, muscle cells in this part of the heart will die, which is the essence of a heart attack.

The major risk factors for coronary atherosclerosis are high blood pressure, high cholesterol, smoking, poor diet and a lack of activity. Unfortunately, as people get older, heart attacks can happen even in people without risk factors. Blockages in the heart may cause angina — chest pain or pressure, especially with exertion, that is often accompanied by sweating or shortness of breath.

However, coronary atherosclerosis may not cause symptoms, as the blockages can be small enough not to interfere with the blood flow when they rupture. This is why screening for risk factors is so important, even in young people. The newest guidelines recommend screening blood cholesterol levels at age 30.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu.