Do apolipoprotein E genotype and educational attainment predict the rate of cognitive decline in normal aging? A 12-year follow-up of the Maastricht Aging Study.
OBJECTIVE
We investigated suspected longitudinal interaction effects of apolipoprotein E (APOE) genotype and educational attainment on cognitive decline in normal aging.


METHODS
Our sample consisted of 571 healthy, nondemented adults aged between 49 and 82 years. Linear mixed-models analyses were performed with four measurement time points: baseline, 3-year, 6-year, and 12-year follow-up. Covariates included age at baseline, sex, and self-perceived physical and mental health. Dependent measures were global cognitive functioning (Mini-Mental State Examination; Folstein, Folstein, & McHugh, 1975), Stroop performance (Stroop Color-Word Test; Van der Elst, Van Boxtel, Van Breukelen, & Jolles, 2006a), set-shifting performance (Concept Shifting Test; Van der Elst, Van Boxtel, Van Breukelen, & Jolles, 2006b), cognitive speed (Letter-Digit Substitution Test; Van der Elst, Van Boxtel, Van Breukelen, & Jolles, 2006c), verbal learning (Verbal Learning Test: Sum of five trials; Van der Elst, Van Boxtel, Van Breukelen, & Jolles, 2005), and long-term memory (Verbal Learning Test: Delayed recall).


RESULTS
We found only faint evidence that older, high-educated carriers of the APOE-ε4 allele (irrespective of zygosity) show a more pronounced decline than younger, low-educated carriers and noncarriers (irrespective of educational attainment). Moreover, this outcome was confined to concept-shifting performance and was especially observable between 6- and 12-year follow-ups. No protective effects of higher education were found on any of the six cognitive measures.


CONCLUSIONS
We conclude that the combination of APOE-ε4 allele and high educational attainment may be a risk factor for accelerated cognitive decline in older age, as has been reported before, but only to a very limited extent. Moreover, we conclude that, within the cognitive reserve framework, education does not have significant protective power against age-related cognitive decline.
Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, the Netherlands. p.vangerven@maastrichtuniversity.nl
Pascal W M
PW
Van Gerven
Martin P J
MP
Van Boxtel
Eleonora E B
EE
Ausems
Otto
O
Bekers
Jelle
J
Jolles
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics* / Q000523:psychology*; D001057:Apolipoproteins E / Q000235:genetics*; D001288:Attention / Q000502:physiology; D003072:Cognition Disorders / Q000235:genetics* / Q000523:psychology*; D004522:Educational Status; D005260:Female; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D013997:Time Factors; D014706:Verbal Learning / Q000502:physiology
D001057:Apolipoproteins E