RESUMO
Objective To investigate the relative percentage of normal cognitive function (NCF),age associated memory impairment (AAMI),mild cognitive impairment (MCI) and Alzheimer's disease (AD) in the elderly,and the correlation between cognitive function and ApoE genotypes.Methods A total of 2666 elderly people aged ≥65 years (2132 males and 534 females)were divided into 3 groups according age:65-74-year age group (925 cases),75-84 year age group (1054 cases) and 85-100-year age group (687 cases).ApoE genotypes were determined in the controls and patients with AAMI and MCI.The degrees of fundus arteriosclerosis were detected in all subjects except for patients with AD.Results There were 867 cases with NCF,860 cases with AAMI and 782 cases with MCI.The incidence of AAMI was higher in 65-74-year age group than in the other two groups (42.0％ vs.31.1,20.96).The incidences of MCI and AD were higher in 85-100-year age group than in the other groups (42.5％,13.3％).The major degrees of fundus arteriosclerosis were Ⅰ+,Ⅰ-Ⅱ°,Ⅱ in subjects with AAMI (34.7％,x2=10.02,P＜0.01) and were Ⅱ °/ Ⅱ + / Ⅲ° in subjects with MCI (34.9 ％,x2 =23.39,P＜0.001).The APOEε4 allele frequency was significantly higher in patients with MCI than in the controls (x2=8.31,P＜0.05).However,no significant differences in APOEε4 allele frequency were found between patients with AAMI and the controls.Conclusions The incidence of AAMI is highest in 65-74-year age group,while the incidences of MCI and AD are highest in 85-100-year age group.Compared to patients with AAMI,the more serious fundus arteriosclerosis and higher allele frequency of APOEε4 appear in patients with MCI.