Back in the day, Army researchers performed autopsies on Korean War soldiers who died in the line of action. What they found astounded them and radically changed our view of heart disease.

Nearly 77 percent of these young men showed some sign of arteriosclerosis. These weren’t 60-year-olds, these were 20-year-olds in the prime of their lives.

How could they have hardening of the arteries?

At the time, this was thought of as an old man’s disease. You can see how women took a back seat when it came to medical care back then.

The medical establishment sprang into action, looking at factors that caused this. The result: We now know that lifestyle matters. Stop smoking, start exercising, eat right, lose weight.

We also learned more about medications – including high blood pressure meds and cholesterol pills – and cardiac procedures such as stents and bypass surgery. All of this has added nearly 10 years to our average longevity.

Dramatic, isn’t it?

But a new study shows we shouldn’t rest on our laurels. A recent article in the Journal of the American Medical Association shows that heart disease is still prevalent in our young men and women serving in the military.

Between 2001 and 2011, researchers performed autopsies on nearly all U.S. soldiers who died in combat or from unintentional injuries during the wars in Iraq. That included 4,000 men and women whose average age was 26.

What those autopsies found was good news and bad news.

The overall arteriosclerosis rate had dropped to 12 percent, far lower than Korea. But that still meant that one out of eight military personnel had undiagnosed hardening of the arteries. And what shocked me was that 2.3 percent of these young people had severe heart disease.

Think about this, now: Soldiers traipsing around in the field, doing much more physical and hazardous work than you and I do, some of them in the prime of their lives, already have heart disease – with no symptoms at all. Doesn’t this shock you? It certainly shocks me.

Diving deep into the data, researchers found other risk factors. Those who smoked or were overweight were more at risk. No shock here, is there? But something else fascinated me. Soldiers who had dropped out of high school or had come from a poor family had higher risk. Soldiers, who had one to two years of post-high school education, in college or tech school, had lower risk.

So education seems to form a protective shield against heart disease. That’s a “wow,” isn’t it?

My spin: Whether you’re young or old, lifestyle counts. And what we doctors have failed to recognize is that education and a good-paying job might count just as much. Maybe we should start to say: Stay in school, you’ll live longer. Stay well.

Dr. Zorba Paster is a family physician, university professor, author and broadcast journalist. He also hosts a popular radio call-in program at 3 p.m. Saturdays on WNED.