C-reactive Protein Varies According to Genetic Heritage

C-reactive protein is found in the blood and the levels rise in response to inflammation and is linked to a higher risk for heart disease.

Even though high C-reactive protein (CRP) blood levels have been associated with a greater chance of developing heart disease, the link is uncertain if the association is casual. It is synthesized by the liver in response to factors released by adipocytes (fat cells). Scientists are not sure whether the CRP-lowering effects of statins have any health benefits.

In a study, carried out at the University College London (UCL; London, UK), investigators examined data on 221,287 individuals from 89 published studies. The risk cut-off point used was 2 mg/L based on the findings of the US Food and Drug Administration (FDA; Silver Spring, MD, USA) for males over 50 and females over 60 who have one other heart disease risk factor as well as CRP values over the this level.

The scientists found that CRP blood levels vary according to ethnicity, even after such factors as age and body mass index (BMI) has been taken into account. They found the following geometric mean CRP levels according to ancestry: 2.6 mg/L in 18,585 African-Americans; 2.51 mg/L in 5,049 Hispanics; 2.34 mg/L in 1,053 South Asians; 2.03 mg/L in 104,949 Caucasians; and 1.01 mg/L in 39,521 East Asians. The order remained unchanged when the investigators calculated the probability that individuals in each ethnic group would exceed the 2 mg/L CRP threshold at any age. Over 50% of Hispanics and African-Americans were over the 2 mg/L CRP threshold at the age of 50, compared to fewer than half of East Asians. At the age of 60 under 40% of East Asians and nearly two-thirds of African-Americans and Hispanics would likely have a CRP greater than 2 mg/L.

Tina Shah, Ph.D., coauthor of the study, noted that, "The difference in average population CRP values in populations of different ancestry are sufficiently large as to have bearing on clinical management and statin eligibility based on single CRP cut-off point values." The study was published online on September 28, 2010 in Circulation: Cardiovascular Genetics.

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