Apolipoprotein e genotype, cortisol, and cognitive function in community-dwelling older adults.
BACKGROUND
Elevated cortisol indicates stress and may be a risk factor for cognitive decline in aging. Genetic factors may influence individual vulnerability to the adverse effects of stress on cognitive function in aging.


METHODS
The authors investigated whether the gene-environment interaction between the genotype for the apolipoprotein E gene (APOE) and cortisol predicted cognitive performance in older urban adults. Cross-sectional data were analyzed from a population-based sample of 50-70-year-old men and women. Cognitive performance, salivary cortisol levels, and APOE genotype were assessed in 962 subjects. Scores on 20 standard cognitive tests were combined into seven domain scores (language, processing speed, eye-hand coordination, executive functioning, verbal memory and learning, visual memory and learning, visuoconstruction).


RESULTS
In adjusted models, while a higher cortisol level was associated with worse cognitive scores, the slopes of the adverse relations were steeper in persons with at least one APOE-epsilon4 allele. Effect sizes were large: for example, the effect of having one epsilon4 allele plus a cortisol area under the curve greater than the 75th percentile was equivalent to a decrease in language score expected from an age increase of 8.0 years (95% confidence interval=1.7-14.4), while having two epsilon4 alleles and a cortisol area under the curve greater than the 75th percentile was equivalent to an age increase of 33.4 years (95% CI=14.8-52.0).


CONCLUSIONS
These data suggest that APOE genotype modifies cortisol's relations with cognitive functioning and that the epsilon4 allele increases vulnerability of the aging brain to adverse effects of stress.
Lee
Brian K
BK
Division of Occupational and Environmental Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
Glass
Thomas A
TA
Wand
Gary S
GS
McAtee
Matthew J
MJ
Bandeen-Roche
Karen
K
Bolla
Karen I
KI
Schwartz
Brian S
BS
D000368:Aged; D000483:Alleles; D000544:Alzheimer Disease / Q000097:blood / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D053327:Apolipoprotein E4 / Q000235:genetics*; D015142:Baltimore; D003072:Cognition Disorders / Q000097:blood / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D003430:Cross-Sectional Studies; D005260:Female; D005838:Genotype; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011594:Psychometrics
D053327:Apolipoprotein E4; D006854:Hydrocortisone