That might be difficult to believe, but the top health concern of millions of Americans is about to be trumped by what medical researchers say is an even bigger trigger of heart attacks.
The condition is low-grade inflammation, which may originate in a variety of unlikely places throughout the body, including excess fat. New federal recommendations are being written that will urge doctors to test middle-aged and older Americans for it. The discovery of its surprising ill effects is causing a top-to-bottom re-thinking of the origins and prevention of heart trouble.
Conventional doctors call it a revolutionary departure from viewing the world's top killer as largely a plumbing problem blamed on cholesterol-clogged arteries, which is the standard theoryin modern cardiology.
"The implications of this are enormous," says Dr. Paul Ridker of Boston's Brigham and Women's Hospital. "It means we have an entire other way of treating, targeting and preventing heart disease that was essentially missed because of our focus solely on cholesterol."
In the past few years the evidence has become overwhelming that inflammation hidden deep in the body is a common trigger of heart attacks, even when plaquing in the arteries is minimal. Inflammation can be measured with a generic $10 test that looks for high levels of a chemical called C-reactive protein (CRP), one of many that increase during inflammation.
While measuring cholesterol is still an important consideration, it is noteworthy that half of all heart attack victims have levels that are normal or even low. Clearly, something big has been missing from the equation, and that something appears to be inflammation.
Ridker estimates that between 25 million and 35 million seemingly healthy middle-aged Americans have normal cholesterol but above-average inflammation, putting them at unusual risk of heart attacks and strokes. A series of landmark studies by his team beginning in 1997 suggest that inflammation is a better predictor of heart attacks than cholesterol. They found those with high levels of CRP have double the risk of people with elevated cholesterol. High amounts of CRP also predict increased risk of heart attacks and strokes years before they occur, even when cholesterol levels are low.
Having both inflammation and high cholesterol together is especially ominous, resulting in a NINE-FOLD increase in risk.
Nearly everyone who reaches middle age has at least some degree of fatty buildup, known as plaque, in the arteries. The new evidence suggests it becomes threatening if weakened by inflammation, which makes it squishy and fragile. Even a small lump of plaque can burst, prompting the formation of a clot that in turn chokes off blood flow and causes a heart attack or stroke.
Many people with no outward signs of anything wrong have high levels of internal inflammation. It is exactly the same sort that causes swelling, heat, and redness during infections or allergic rashes.
Researchers believe the internal inflammation has many possible sources. Often, the plaque itself becomes inflamed as immune cells invade the area in a defense response. But inflammation that arises elsewhere apparently can be just as bad, because it bombards the plaque with damaging chemicals.
For example, fat cells churn out these inflammatory mediators, which is one of many reasons why being overweight is so bad for the heart. Fat cells, or adipocytes, are now being referred to as “endocrine organs” by researchers because of their ability to “talk” to the rest of body through inflammatory mediators, and the language they speak is one of alarm. Being overweight sets off an ongoing state of alarm throughout the body through the production of inflammatory chemicals, and they in turn can cause muscle tissue breakdown and a catabolic snowball process that leads to more inflammation, more production of fat cells, and an accelerated rate of aging and degeneration through increased oxidation.
Other possible triggers of CRP include high blood pressure, smoking and lingering low-level infections such as chronic gum disease.
Although many chemicals increase during inflammation, CRP is particularly easy to measure. Many doctors believe that CRP should measured in everyone over age 40, just like cholesterol, regardless of their other risk factors like cholesterol or high blood pressure.
"It begins to look like a standard risk factor that one would evaluate at least once in middle age in most people," says Dr. Wayne Alexander of Emory University. "This is a very important concept for the general public to be aware of and to think about for their own health."
"We believe the niche for C-reactive protein - and it is a large niche - is the healthy population who want to do what they can to lower their risk of cardiovascular disease," says Dr. Richard Cannon of the National Heart, Lung and Blood Institute.
Screening is important because inflammation can be readily lowered in several ways. One of the most powerful is losing weight. Exercise also helps, as does moderating alcohol intake, giving up smoking and lowering one’s blood pressure. Thus, doctors are likely to urge these habits for people with high CRP readings who until now would have seemed to be at no special risk of heart problems.
"In the last decade, people talked about their cholesterol levels," Dr. Cannon says. "In the next decade, the cocktail chatter will be, 'What's your C-reactive protein?' Everyone will need to know that."
