Biomarker doesn't predict high blood pressure

For young adults in their 30s, a blood test for C-reactive protein (CRP), which is linked to inflammation, is unlikely to predict the future risk of high blood pressure, according to a study released this week.

There is increasing evidence that inflammation is related to high blood pressure, Dr. Susan G. Lakoski, from Wake Forest University School of Medicine in Winston-Salem, North Carolina and colleagues note in the Archives of Internal Medicine.

The presence of CRP often indicates low-level ongoing inflammation. In a previous study of women in their 50s, raised CRP levels, as a marker of inflammation, predicted the development of high blood pressure, independent of other risk factors such as obesity.

"My question," Lakoski said, "was, in a younger group of individuals, mainly black and white people in their 30s, would CRP independently predict hypertension? It did not. I think it's an important question that we have answered," she said.

The findings are based on more than 3,900 adults between the ages of 25 and 37 who had CRP levels measured in 1992 and 1993 as part of The Coronary Artery Risk Development in Young Adults (CARDIA) study. The rate of high blood pressure was determined in these individuals in 2000 and 2001.

When factors that contribute to the development of high blood pressure, such as weight, sex and race were factored in, CRP was not independently associated with the future risk of high blood pressure, Lakoski said.

It's possible that obesity, which is an important predictor of high blood pressure in and of itself, confounds the relationship between CRP and high blood pressure, the authors offer. The results of previous studies suggest that obesity is an important factor in high blood pressure, but that is not what we looked at in this study, Lakoski said.

The findings, the authors conclude, suggest that CRP level in young adults is unlikely to help predict the development of high blood pressure in middle age.

SOURCE: Archives of Internal Medicine, February 13, 2006.