LpA-I, LpA-I:A-II HDL and CHD-risk: The Framingham Offspring Study and the Veterans Affairs HDL Intervention Trial

Objective We tested the hypothesis that concentrations of LpA-I and/or LpA-I:A-II HDL subclasses are significantly associated with CHD prevalence and recurrent cardiovascular events. Methods LpA-I levels were determined by differential electroimmunoassay in male participants with (n = 169) and without CHD (n = 850) from the Framingham Offspring Study (FOS) and in male participants with CHD from the placebo arm of the Veterans Affairs HDL Intervention Trial (VA-HIT) (n = 741). Data were analyzed cross-sectionally (FOS) and prospectively (VA-HIT) and were adjusted for established lipid and non-lipid CHD risk factors. Results We observed slightly but significantly higher LpA-I levels in CHD cases compared to all or to HDL-C-matched controls and slightly but significantly higher LpA-I:A-II levels in CHD cases compared to HDL-C-matched controls it the FOS. Neither LpA-I nor LpA-I:A-II levels were significantly different between groups with and without recurrent cardiovascular events in the VA-HIT. No significant differences were observed in LpA-I and LpA-I:A-II levels in low HDL-C (≤40mg/dl) subjects with CHD (VA-HIT, n = 711) and without CHD (FOS, n = 373). Plasma LpA-I concentration had a positive correlation with the large LpA-I HDL particle (α-1) but no correlation with the small LpA-I HDL particle (preβ-1). LpA-I:A-II concentration had a positive correlation with the large (α-2) and an inverse correlation with the small (α-3) LpA-I:A-II HDL particles. Conclusion Our data do not support the hypothesis that CHD prevalence (FOS) or recurrence of cardiovascular events (VA-HIT) are associated with significant reductions in the concentrations of LpA-I and/or LpA-I:A-II HDL subclasses.