Half of all heart attacks in the U.S. occur in people with normal cholesterol levels. Baffled? So were doctors, until November. That's when Dr. Paul Ridker at Boston's Brigham and Women's Hospital confirmed a separate, perhaps equally powerful, risk factor for heart disease: inflammation, the same culprit behind arthritis and other autoimmune diseases. Smaller studies had hinted at the link in the past, but Ridker's recent research, published in the New England Journal of Medicine, showed that when people with normal cholesterol and high levels of CRP — a protein marker for inflammation in the blood — took statins, their CRP levels plummeted and their heart attack risk fell 54%. Compare that to the 20% reduced risk in people who take statins to lower cholesterol alone. Doctors say cholesterol and fatty plaques are still the main indicators of heart disease, but inflammation may be just as important, playing a key role as a trigger: It increases the instability of plaques, making them more likely to rupture, block heart vessels and cause a heart attack.