DALLAS (American Heart Association) -- There is a significant association between body mass index and C-reactive protein (CRP) levels in children, according to a study in the rapid access issue of Circulation: Journal of the American Heart Association.

"This finding suggests that the inflammatory component of heart disease might be present very early in life," says Earl S. Ford, M.D., M.P.H., medical officer in the Division of Adult and Community Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention in Atlanta.

Body mass index (BMI) is a measure of overall body fatness. Among the study participants, blood levels of CRP increased as BMI increased.

"These findings are interesting from a research perspective," Ford says, "but they do not make a case for testing CRP in all children. CRP has received a fair amount of attention in adults, but we really didn't know much about it in children. However, as with any risk marker, it is useful to look at potential relationships in different age groups."

Ford analyzed data collected by the National Health and Nutrition Examination Survey (NHANES), 1999-2000, a cross-sectional study of the U.S. population. The study included data from 1,479 boys and 1,367 girls ages three to 17. The NHANES survey collects several health measures including age, body mass index, blood pressure and CRP (measured with a high-sensitivity test).

Ford says that while body mass index was the best predictor of CRP concentrations in both boys and girls, it was not the only association identified in his analysis. CRP was higher in older boys suggesting an association with age. For girls ages 12 to 17, as CRP increased, so did systolic blood pressure. Systolic blood pressure is the top number in a blood pressure reading.

CRP concentrations ranged from 0.1 milligrams per liter (mg/L) to 65.2 mg/L among the boys and from 0.1 mg/L to 46.6 mg/L for girls.