Associations Between Apolipoprotein E Phenotype, Glucose Metabolism and Cognitive Function in Men. An Explorative Study in a Population Sample

Aims To investigate the associations of the apolipoprotein E phenotype (apoE) and disturbed glucose metabolism with cognitive function in a random population sample. Methods A cross-sectional study was conducted, in which 528 men aged 54 or 60 years were recruited randomly from a larger population-based sample of 1516 men. A subject was defined as having abnormal glucose tolerance (AGT), if he had a clinical diagnosis of diabetes, with either dietary or oral antidiabetic treatment or showed impaired glucose tolerance in an oral glucose tolerance test. The subjects were divided into three groups according to apolipoprotein E phenotypes: (a) E2/4, E3/4 or E4/4 (apoE E4); (b) E 3/3 (apoE E3); and (c) E2/2 or E2/3 (apoE E2). Memory function was examined using a word-list learning with Buschke's selective reminding method and test. Executive functions were assessed with the Trail Making Test A and B. Results Those subjects with apoE E2 and abnormal glucose metabolism demonstrated the worst cognitive executive control compared to other groups. Simple cognitive speed did not differ between the groups. Conclusions The exploratory analyses revealed that subjects with apoE E2 allele and AGT had worse glycaemic control and cognitive executive control compared to other groups. Different apolipoprotein phenotypes together with impaired glucose tolerance may have different cumulative adverse effects on age-related cognitive performance. Some subgroups of subjects may be especially vulnerable to cognitive impairment.