Particle Size Not Cholesterol Determines Capacity of HDL to Reduce CVD

Results of a recent study suggested that the number and size of high-density lipoprotein (HDL) particles in the blood were better indicators of cardiovascular disease (CVD) risk than was the classical measurement of HDL-cholesterol.

To try to explain why treatments to elevate plasma high-density lipoprotein cholesterol (HDL-C) fail to reduce CVD risk, investigators at the Hebrew University of Jerusalem (Israel) recruited a study population comprising 504 Jerusalem residents (274 Arabs and 230 Jews). The participants' HDL was measured and classified by NMR spectroscopy, and calcification in their coronary arteries (CAC), reflecting the overall burden of coronary atherosclerosis, was determined by multidetector helical CT-scanning.

Results revealed that HDL-C was not protectively associated with CAC, but that HDL particle number (HDL-P) was strongly protectively associated with CAC. Small and medium-sized HDL (MS-HDL-P) and HDL-P accounted for the protective effects of HDL-P. Large HDL-P and average HDL-P size were not significantly associated with CAC. Therefore, MS-HDL-P and HDL-P were better risk markers for CAC than the traditional HDL-C.

"Our findings indicate that HDL-P and MS-HDL-P are better independent markers of coronary artery disease, as reflected by coronary artery calcification, than HDL-C, at least in this bi-ethnic population of Israelis and Palestinians," said first author Dr. Chobufo Ditah, (from Cameroon) a master of public health student at the Hebrew University of Jerusalem. "These findings support previous reports, based on studies in other population groups, suggesting that small dense HDL particles are protectively associated with risk of coronary heart disease. The consistency of this finding in a new population of urban Arabs and Jews, using different disease outcomes and different separation methods, add more strength to those findings."

"With a better understanding of HDL's complexity and a better ability to measure its components, it is now possible to move past HDL-C to more refined measures that better reflect HDL's role in coronary heart disease risk. Based on the accumulating evidence, incorporation of MS-HDL-P or HDL-P into the routine prediction of coronary heart disease risk should be considered," said senior author Dr. Jeremy Kark, professor of epidemiology at the Hebrew University of Jerusalem.

The study was published in the August 2016 issue of the journal Atherosclerosis.

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Hebrew University of Jerusalem