The C-reactive protein (CRP) test has become a popular way to check for inflammation that is linked to heart disease. But CRP's value as a predictor of heart disease has remained a subject of medical debate.
C-reactive protein is produced by the liver and is present when there is inflammation anywhere in the body. But a CRP test cannot indicate where the inflammation is located or what is causing it.
A new study published in the Dec. 16, 2004 issue of The New England Journal of Medicine supports the theory that CRP helps calculate heart disease risk.
Researchers at Harvard investigated the role of CRP in association with three other markers of inflammation and found that "the level of C-reactive protein is a significant marker of the risk of coronary heart disease," even after taking into account other risk factors that increase the risk of heart disease.
The results were based on blood samples from hundreds of participants of the Nurses' Healthy Study and the Health Professionals Follow-up Study. The men and women in these studies did not have heart disease at the start of the study. Additional blood samples were taken over the six- to eight-year study periods.
During this time, more than 500 of the participants suffered heart attacks, some fatal. The researchers show that high blood levels of CRP at the start of the study significantly increased the risk of heart attack in people without heart disease.
The researchers also found that blood cholesterol levels were more strongly associated with an increased heart disease risk than CRP or other inflammatory markers.