The association of APOE genotype and cognitive decline in interaction with risk factors in a 65-69 year old community sample.
BACKGROUND
While the evidence of an association between the apolipoprotein E (APOE) *E4 allele and Alzheimer's disease is very strong, the effect of the *E4 allele on cognitive decline in the general population is more equivocal. A cross-sectional study on the lifespan effects of the *E4 allele 1 failed to find any effect of the *E4 allele on cognitive performance at ages 20-24, 40-44 or 60-64 years.


METHODS
In this four year follow-up study, we reexamine the effect of *E4 in the sample of 2,021 individuals, now aged 65-69 years.


RESULTS
Performance on the Mini-Mental State Examination (MMSE) was significantly poorer for *E4 homozygotes than heterozygotes or non-carriers. The effects of the *E4 genotype on cognitive decline over four years were found on the MMSE and Symbol-Digit Modalities test but only when controlling for risk factors such as head injury and education. Analyses were repeated with the exclusion of participants diagnosed with a mild cognitive disorder, with little change.


CONCLUSIONS
It is possible that *E4 carriers become vulnerable to greater cognitive decline in the presence of other risk factors at 65-69 years of age.
Christensen
Helen
H
The Australian National University, Canberra, Australia. helen.christensen@anu.edu.au
Batterham
Philip J
PJ
Mackinnon
Andrew J
AJ
Jorm
Anthony F
AF
Mack
Holly A
HA
Mather
Karen A
KA
Anstey
Kaarin J
KJ
Sachdev
Perminder S
PS
Easteal
Simon
S
D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000235:genetics; D001057:Apolipoproteins E / Q000235:genetics*; D001315:Australia; D003072:Cognition Disorders / Q000175:diagnosis / Q000235:genetics*; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D015577:Geriatric Assessment / Q000379:methods*; D006579:Heterozygote; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
D001057:Apolipoproteins E