Comparison of nonfasting and fasting lipoprotein subfractions and size in 15,397 apparently healthy individuals: An analysis from the VITamin D and OmegA-3 TriaL

Abstract

Background: Elevated postprandial triglycerides reflect a proatherogenic milieu, but underlying mechanisms are unclear.

Objective: We examined differences between fasting and nonfasting profiles of directly measured lipoprotein size and subfractions to assess if postprandial triglycerides reflected increases in very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL) and remnants, or small dense lipid depleted LDL (sdLDL) particles.

Methods: We conducted a cross-sectional analysis of 15,397 participants (10,135 fasting; 5262 nonfasting [<8 hours since last meal]) from the VITamin D and OmegA-3 TriaL. Baseline cholesterol subfractions were measured by the vertical auto profile method and particle subfractions by ion mobility. We performed multivariable linear regression adjusting for cardiovascular and lipoprotein-modifying risk factors.

Results: Mean age (SD) was 68.0 years (±7.0), with 50.9% women. Adjusted mean triglyceride concentrations were higher nonfasting by 17.8 ± 1.3%, with higher nonfasting levels of directly measured VLDL cholesterol (by 3.5 ± 0.6%) and total VLDL particles (by 2.0 ± 0.7%), specifically large VLDL (by 12.3 ± 1.3%) and medium VLDL particles (by 5.3 ± 0.8%), all P < .001. By contrast, lower concentrations of low density lipoprotein (LDL) and IDL cholesterol and particles were noted for nonfasting participants. sdLDL cholesterol levels and particle concentrations showed no statistically significant difference by fasting status (-1.3 ± 2.1% and 0.07 ± 0.6%, respectively, P > .05).

Conclusions: Directly measured particle and cholesterol concentrations of VLDL, not sdLDL, were higher nonfasting and may partly contribute to the proatherogenicity of postprandial hypertriglyceridemia. These differences, although statistically significant, were small and may not fully explain the increased risk of postprandial hypertriglyceridemia.

Trial registration: ClinicalTrials.gov NCT01169259.

Keywords: Lipoprotein subfractions; Nonfasting lipids; Postprandial state; Triglyceride-rich lipoproteins.

Copyright © 2020 National Lipid Association. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

is the graphical representation of the percent difference in lipid and lipoprotein concentrations (and LDL pattern) in nonfasting vs. fasting participants. p-value < 0.0001 represented by ***; p-value <0.001 by ** and p-value <0.05 by *.

Figure 2

is the graphical representation of the percent difference in size separated lipoprotein subfractions and LDL peak size by ion mobility in nonfasting vs. fasting participants. p-value < 0.0001 represented by ***; p-value <0.001 by ** and p-value <0.05 by *.

Figure 3

Graph of mean lipid and lipoprotein levels as a function of time since last meal using cubic spline regression with associated 95 percent confidence intervals. Total Very Small LDL-P is the sum of all the very small LDL particle subfractions: a+b+c+d.