Relationship Between the Apolipoprotein E Genotype and LDL Particle Size in Patients With Obstructive Sleep Apnea

Abstract

Obstructive sleep apnea (OSA) is associated with dyslipidemia and increased cardiovascular risk. We assessed the effects of apolipoprotein E (APOE) genotype on low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particle size and lipid subclasses (separated by gradient gel electrophoresis) in patients with OSA. Stable patients (n = 181) prospectively recruited underwent full polysomnography. Both LDL particle size and LDL I proportion were reduced from 33 homozygotes to 2 carriers and to 4 carriers (analysis of variance: P = .024; P = .040, respectively); carriers of the 4 allele of the APOE genotype had significantly lower LDL particle size and LDL I proportion compared to 33 homozygotes (P lt .05 for both comparisons). Insulin resistance increased from patients with no OSA to those with mild-moderate and to those with severe OSA (P lt .001). In multivariate analysis, LDL size was independently predicted by APOE genotype, male gender, and the presence of metabolic syndrome (MetS; P = .001, P = .020, P = .027, respectively). The HDL particle size was not affected by APOE genotype. Our data demonstrate that both the 4 APOE genotype and MetS are independently related to smaller LDL size in patients with OSA.