Association between apolipoprotein E gene polymorphisms and serum lipid indicators and Alzheimer's disease risk

BackgroundApolipoprotein E (<i>APOE</i>) polymorphisms, particularly the <i>APOE4</i> genotype, are established genetic risk factors for Alzheimer's disease (AD). However, the clinical utility of combining <i>APOE</i> genotypes with serum lipids and blood-based AD biomarkers remains incompletely defined.ObjectiveTo investigate the association between <i>APOE</i> gene polymorphisms, serological indicators, and the occurrence of AD.MethodsBlood samples of 109 patients with AD and 85 non-AD participants were used to detect <i>APOE</i> genotypes. Serum levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), amyloid-β 1-42 (Aβ_1-42), and p-tau-181 were measured. Receiver operating characteristic analysis was performed in an independent validation set of 82 cases.ResultsThe frequency of the <i>APOE4</i> genotype was significantly higher in the AD group compared with the non-AD group, whereas <i>APOE2</i> and <i>APOE3</i> genotypes showed no significant differences. TC, HDL-C, and LDL-C levels were significantly elevated in the AD group compared with the non-AD group, while TG, Aβ_1-42, and p-tau-181 levels did not differ significantly. Among patients with AD carrying the <i>APOE4</i> genotype, TC and LDL-C levels were significantly higher than those in non-AD <i>APOE4</i> carriers. Further, within the AD group, <i>APOE4</i> carriers had a significantly higher proportion of elevated TC and LDL-C levels than non-<i>APOE4</i> carriers. Validation experiments revealed that the combination of <i>APOE4</i> genotype with elevated TC and LDL-C demonstrated greater diagnostic efficacy for AD.Conclusions<i>APOE4</i> genotype combined with elevated TC and LDL-C levels strongly correlate with AD onset and may be valuable auxiliary biomarkers for AD diagnosis and treatment.