Relation of apolipoprotein(a) size to Alzheimer's disease and vascular dementia

Lipoprotein(a)[Lp(a)] level is a newly established vascular risk factor which has been suggested to play a role in dementia. However, the majority of Lp(a) cell-to-cell interactions are mediated by its specific apolipoprotein(a)[apo(a)] moiety. This suggests that the size polymorphism of apo(a) may be of importance in conveying the Lp(a)-related risk. Specifically, we postulated that variation in apo( a) isoform size may lead to increased risk of vascular dementia (VaD), Alzheimer's disease (AD), stroke, or all three of them. Under a case-control design we compared Lp(a) plasma levels and the distribution of apo(a) phenotypes in groups of subjects consisting of 50 VaD patients, 162 sporadic AD patients, 95 non-demented stroke patients (NDS), and 105 normal controls. The prevalence of small-sized apo(a)isoforms in the VaD group was significantly higher than that in the stroke and normal control groups, with an odds ratio of 5.29 (95% CI 2.24-12.49, p=0.0001) for the development of VaD for individuals with at least one apo( a) isoform of low molecular weight (LMW). Furthermore, the possession of at least one small-sized apo(a) isoform significantly increased the risk of AD to 1.92 (95% CI 1.02-3.61, p=0.0434). Our results demonstrate that possession of at least one LMW apo(a) isoform is significantly associated with dementia and specifically offer new evidence of a strong association between the lipoprotein system and post-stroke dementia. Copyright (C) 2004 S. Karger AG, Basel.