Background: Copper (Cu) and zinc (Zn) have been implicated in the development of Alzheimer's disease (AD) and, in this regard, Cu and Zn serum concentrations have been analysed but with inconclusive results. Serum insulin, glucose and cholesterol concentrations have been related to the apolipoprotein E genotype in non-AD populations.
Design: In this study, we have analysed the relationship between serum Cu, Zn, insulin, glucose and lipid parameters (cholesterol, triglycerides, apoA and apoB apolipoproteins) in AD and AD epsilon 4 apolipoprotein E carriers by multivariate analysis using logistic regression, including the variables that showed a significance of P < 0.05 in the bivariate analysis.
Results: The results obtained show that epsilon 4 apoE allele is an independent AD risk factor (OR = 6. 67, 95% CI = 2.59-17.16). In AD epsilon 4 apoE allele carriers, we found significantly higher Zn, Cu and insulin serum concentrations. Non-demented control subjects with at least one epsilon 4 apoE allele had the lowest serum insulin concentrations. There was no significant association between epsilon 4 apolipoprotein E allele and lipid parameters in the sample studied.
Conclusions: In AD we have found a significant association between higher serum Zn, Cu and insulin concentrations and the presence of an epsilon 4 apoE allele, but only greater serum Zn concentration appears to be an independent risk factor associated with the development of AD.