Abstract

As a part of the WHO Age-Associated Dementia Project, Chile has been participating in a cross-national survey on dementia frequency and determinants since 1989. In the present study, apolipoprotein E (ApoE) polymorphism genotypes have been compared in 95 patients with Alzheimer's disease (AD) (mean age 80.7; 95% CI 79.2-82.2, range 6697) and 187 healthy people (mean age 78.2; 95% CI 77.2-79.2, range 65-93). Isoelectric focusing and immunoblotting with anti-human ApoE polyclonal antibody were used to determine the distribution of ApoE genotypes. Dementia was diagnosed according to DSM-III-R and ICD-10 clinical criteria. The diagnosis of probable or possible AD was made according to the NINCDS-ADRDA criteria. The ApoE allele frequencies in healthy people were calculated to be ?2=0.07, ?3=0.74 and ?4=0.19. In the probable AD disease group, the frequencies were ?2=0.08, ?3=0.52 and ?4=0.40. The odds ratio (OR) for ?4 carriers compared with non-?4 carriers was estimated to be 2.9 (95% CI 1.7-5.1). Taking the genotype ?3/?3 as the reference group, the OR for the ?4/?4 genotype was estimated to be 12.8 (95% CI 3.9-47.6) and for ?3/?4 subjects it was 2.4 (1.3-4.5). These results support the association between ApoE ?4 allele with late-onset AD in a Chilean population.