The results, reported in this month's American Heart Association journal Stroke, indicate that routine check-ups in middle age to look for hidden risk factors may be the key to preventing strokes later in life.

"Things like high blood pressure, smoking, drinking excessively -- these are what we call risk factors," says Dr. Ralph Sacco of Columbia Presbyterian Medical Center. "(Researchers) were able to now find these factors also increase the findings of abnormalities in the brain in later years."

Of all of the risk factors, high blood pressure was considered the strongest. And regular check-ups are key to finding hypertension, because patients often feel perfectly fine and don't know their pressure is elevated.

People can often lower their risk with simple lifestyle changes, including an improved diet and exercise. In some cases, however, medication may be necessary.