When I was told that I have coronary artery disease, I was baffled. After all, I am only 36, and CAD is a condition of the elderly, or so I thought. The heart specialist, however, let me know that anyone may be susceptible to the condition. Coronary artery disease is caused by a buildup of plaque in the arteries of the heart. Uncontrolled blood sugar levels increase the risk of heart attack because the sugar in the blood damages blood vessels throughout the body, including the heart.