Inflammation is the body's natural reaction to infection or injury, like the red swelling around a surface wound. It can also occur in tissues and the blood vessels within body where we can't see or feel it.
It can be caused by the fatty buildups in blood vessels associated with heart disease, but other possible factors include anything that puts low-level but constant pressure on the body's immune system, like high blood pressure or chronic infection.
The good news is that inflammation can be detected early with an inexpensive blood test for the C-reactive protein or CRP, which is produced by the body when it's fighting injury and infection.
This new study offers the strongest evidence yet that inflammation causes heart disease. In the New England Journal of Medicine, researchers in Boston looked at 28,000 women over an eight-year period.
The study showed that women with high levels of CRP were twice as likely as those with high cholesterol to die from heart attacks and strokes. It also showed about half of heart attacks and strokes occurred in those with seemingly safe levels of cholesterol.
Researchers think that the findings apply to men, too, because smaller studies in men have shown similar results.
Lowering CRP Levels
Diet and exercise can lower CRP dramatically. Medications including cholesterol-lowering drugs and aspirin can reduce CRP as well. And the test can predict risk 15 to 25 years in the future, so people with high levels have a long time to make the lifestyle changes necessary to avoid trouble.
The American Heart Association says that a test is likely to be most useful right now for people with other high risk factors for heart problems like age, obesity and high blood pressure.
New guidelines are expected soon that take into account the importance of a CRP test. If further research continues to show that lives can be saved by lowering CRP; it could become as routine as a cholesterol test. The test typically costs between $25 and $50.
Over the past five years, research by Dr. Paul Ridker of Boston's Brigham and Women's Hospital has built the case for the "inflammation hypothesis." With his latest study, many believe the evidence is overwhelming that inflammation is a central factor in cardiovascular disease, by far the world's biggest killer.
"I don't think it's a hypothesis anymore. It's proven," said Dr. Eric Topol, chief of cardiology at the Cleveland Clinic.
Others are reluctant to test people at low outward risk. Dr. Sidney Smith, research director of the American Heart Association, said CRP testing is likely to be most helpful in guiding the care of the 40 percent of U.S. adults already considered at intermediate risk of heart attacks because of other conditions, such as age, obesity and high blood pressure.
"In certain patients the use of this test could be very helpful in motivating them to change their lifestyle," Smith, a professor of medicine at the University of North Carolina, told CBS Radio News - but he doesn't support making blood tests for inflammation part of standard physical exams.
"This test can help predict risk (of heart attack) but we still need to learn more about what to do with it," he said. "(It's) another piece in a puzzle which is very important to solve because heart disease and stroke are the leading cause of death and disability."
In March, the heart association and the Centers for Disease Control and Prevention held a meeting of 50 experts to review the evidence and make recommendations on CRP testing. Although it hoped to be finished this month, the committee went back to the drawing board after learning last week of Ridker's latest results, which are being published in the New England Journal of Medicine.