Association Of The Apolipoprotein E Genotype With Cognitive Function In Community Elderly

Objective:To investigate the relationship between ApoE gene polymorphism and cognitive change in community elders.Method:Random sampling of the community elderly over 60 years old,145 in Changning District,149 in Pudong new District were recruited in this survey.Interviewer training in use of standard psychometric scales.Data collected included general demographic information,information about daily living.Several psychological and psychosocial measures were assessed by a psychologist:MMSE,MOCA,and NTB.Attending-level psychiatrists collected information on the current and past history of diseases,conducted physical examinations,evaluated functioning and determined the diagnosis using the Structured Clinical Interview for DSM(SCID).Re-evaluate the participant at 1 year follow-up.ApoE genotyping was performed by LDR-PCR sequencing.The APOE genotypes were divided into three groups:APOE ?2 group(?2/?2 and ?2/?3),APOE ?3 group(?3/?3);and APOE ?4 group(?2/?4,?3/?4,and ?4/?4).Demographic data,Lifestyle,past history,and laboratory tests were compared between the groups:the general population,the non-demented group and the follow-up group.Comparison of baseline cognitive function was in non-demented group.Comparison of the score of cognitive change(the score of follow up minus the score of baseline),the rate of cognitive change[(follow-up score-baseline score)/baseline score*100%].Carriers of the ?2 or?4 allele were defined as APOE2 or ApoE4 carriers with a variable of 1;non-carriers were given a variable of O.Those having the ?3/?3 genotype were defined as APOE3 carriers with a variable of 1,those carrying other genotypes were defined as non-APOE3 carriers with a variable of 0.These three types of carriers and non-carriers were converted into a dichotomous variable.The demographic data,lifestyle,past history,laboratory tests,baseline cognitive score and score of cognitive change were compared in the group of ApoE2,ApoE3,and ApoE4.Put the subjects which the P<0.20 into the covariate and do the Logistic regression with the ApoE2,ApoE3,and ApoE4 as the dependent variable.Statistical analysis was performed using SPSS 19.0 software.Result:1.294 participants completed the baseline study.The frequency of?3/?3 was the highest(69.6%),The APOE genotype and allele frequency distributions were found to be accordance with Hardy-Weinberg equilibrium.The education of the ApoE?4 group was higher than ApoE?2,and ApoE?3.The mean age of ApoE?4 was younger than ApoE?2.The fasting plasma glucose of ApoE?2 was lower than ApoE?3.ApoE?2 group got the lowest LDL and ApoE?4 got the highest HDL in three groups.ApoE?4 group got higher incidence of dementia with no significant differences in three groups.2.Excluding 21 elderly people with dementia and 7 people with invalid data,a total of 266 non-demented Elderly completed baseline cognitive assessment.Compared with the 266 non-demented elderly,the exclusion group was older and less educated.The scores of MoCA,digit span,verbal learning test-immediate recall and Wechsler block design were different significantly among ApoE?2,ApoE?3,and ApoE?4.After adjusting the age,education and other confounding factors,no significant differences in the cognitive function among ApoE?2,ApoE?3,ApoE?4 groups.3.194 community elderly completed 1 year followed up,and the expulsion rate was 29%.Excluding 15 people with invalid data,179 completed 1 year follow-up evaluation.In ApoE?2 group,the score of digit span and association test were higher at the follow-up.In ApoE?3 group,the scores of verbal learning test-immediate recall,language fluency,delay recall decreased at the follow-up,the score of digit span was higher than baseline.In ApoE?4 group,the score of verbal learning test-immediate recall,delay recall decreased at the follow-up.After controlling for the confounding factors,the change of verbal learning test-immediate recall in the ApoE?4 group was greater than other two groups.The change of the delay recall in the ApoE?2 group was significantly slighter than the other two groups.Comparison rate of cognitive change obtained similar results.4.ApoE2 group was positively correlated with association test,and change of delay recall.ApoE4 group was positively associated with MoCA,negative correlated with change of immediate recall.ApoE3 group was negatively associated with heart disease rate,immediate recall and change of association test.Conclusion:ApoE genotype is associated with cognitive change among community elderly.?2 allele is probably a protective factor on cognitive function,espespecially at primary memory,verbal ability,episodic memory.?4 allele is associated with the faster change of episodic memory among community elderly.