Two Proteins Predict Heart Risk, Even In Children

By Paula Rasich
Reviewed by Elizabeth Klodas, MD, FACC

(CardioSmart) Some studies show that abnormal blood cholesterol levels in children begin damaging arteries early in life. Now, new research reveals that measuring levels of the proteins apolipoprotein A (apoA-1) and apolipoprotein B (apoB) in childhood can predict who will develop hardened arteries (atherosclerosis) later in life.

ApoA-1 helps sweep away cholesterol and other blood fats to the liver for disposal, while ApoB carries those substances to blood vessel walls where they’re more likely to oxidize and cause plaque build up. ApoA-1 can be thought of as representing the good cholesterol particles in the blood stream and apoB as representing the bad. Traditional cholesterol measurements actually assess only part of the cholesterol particles floating around in our blood streams, so many doctors are looking at apoA-1 and apoB as additional indicators of cardiovascular risk.

Markus Juonala, MD, PhD, of the University of Turku in Finland, and colleagues examined data from the Cardiovascular Risk in Young Finns Study, a study looking at the relationship between cardiovascular risk factors in childhood and the development of atherosclerosis later in life.

In this study, 879 children, aged 3 to 18, were followed for 21 years. In 1980, blood levels of apoA-1 and apoB were measured and assessed along with other risk factors including weight, smoking, blood pressure, insulin, c-reactive protein, and cholesterol levels. In 2001, ultrasound tests on the young adults found that those who had high apoB levels or low apoA-1 levels in childhood were more likely to show signs of atherosclerosis in early adulthood. In addition, researchers discovered that the ratio of apoB to apoA-1 was a better predictor of plaque buildup on artery walls than the ratio of LDL (bad) to HDL (good) cholesterol.

“I think there is no question that apoB is superior to both LDL cholesterol and non-HDL cholesterol in determining risk and the adequacy of therapy,” says cardiologist Allan Sniderman, MD, of McGill University in Montreal, Quebec, Canada. “This study adds to the total body of evidence importantly because it means that the disease process is getting underway early. And it means that we should be able to identify more precisely than we presently do who’s really at high risk, and then institute effective preventive therapy earlier in life.”

Tests that measure these protein levels are available. While they don’t replace cholesterol checks, they can be used as a final check on adequacy of prevention measures. The American College of Cardiology and the American Diabetes Association reccomend apoB levels for individuals with known coronary disease or diabetes be below 80 mg/dL. Patients without coronary disease or diabetes but with multiple other risk factors should have apoB levels which fall below 90 mg/Dl.

The results are published in the July 22^nd issue of the Journal of the American College of Cardiology.

Sources:

Juonala et al. Childhood Levels of Serum Apolipoproteins B and A-1 Predict Carotid Intima-Media Thickness and Brachial Endothelial Function in Adulthood. Journal of the American College of Cardiology, 2008.

Allan Sniderman, MD, Edwards Professor of Cardiology, McGill University Health Centre, Montreal, Quebec, Canada.

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