Hopkins PN, Nanjee MN, Wu LL, McGinty MG, Brinton EA, Hunt SC, Anderson JL. Altered composition of triglyceride-rich lipoproteins and coronary artery disease in a large case-control study.
Atherosclerosis 2009;
207:559-66. [PMID:
19524242 DOI:
10.1016/j.atherosclerosis.2009.05.016]
[Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 05/11/2009] [Accepted: 05/16/2009] [Indexed: 12/31/2022]
Abstract
BACKGROUND
Traditional beta-quantification of plasma lipoproteins by ultracentrifugation separates triglyceride-rich lipoproteins (TGRL) from higher density lipoproteins. The cholesterol in the TGRL fraction is referred to as measured very low-density lipoprotein cholesterol (VLDL-C) recognizing that other TGRL may be present. The measured VLDL-C to total plasma triglyceride (VLDL-C/TG) has long been considered an index of average TGRL composition with abnormally high VLDL-C/TG ratios (>or=0.30 with TG>150mg/dL) indicative of atherogenic remnant accumulation (type III hyperlipidemia). However, virtually no reports are available which examine potential associations between CAD and VLDL-C/TG at the lower end of the spectrum.
METHODS AND RESULTS
We performed ultracentrifugation in 1170 cases with premature-onset, familial CAD and 1759 population-based controls and examined the VLDL-C/TG ratio as an index of TGRL composition. As expected, we found very high CAD risk associated with severe type III hyperlipidemia (OR 10.5, p=0.02). Unexpectedly, however, we found a robust, graded, and independent association between CAD risk and lower than average VLDL-C/TG ratios (p<0.0001 as ordered categories or as a continuous variable). Among those in the lowest VLDL-C/TG category (a ratio <0.12), CAD risk was clearly increased (OR 4.5, 95% CI 2.9-6.9) and remained significantly elevated in various subgroups including those with triglycerides below 200mg/dl, in males and females separately, as well as among those with no traditional CAD risk factors (OR 5.8, 95% CI 1.5-22). Significant compositional differences by case status were confirmed in a subset whose samples were re-spun with measurement of lipids and apolipoprotein B (apo B) in each subfraction.
CONCLUSIONS
We found a strong, graded, independent, and robust association between CAD and lower VLDL-C/TG ratios. We consider this a novel, hypothesis-generating observation which will hopefully generate additional future studies to provide confirmation and further insight into potential mechanisms.
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