The effects of prolonged stress and APOE genotype on memory and cortisol in older adults.
BACKGROUND
Chronic elevations in cortisol associated with prolonged stress have been associated with memory loss, as has the apolipoprotein E gene (APOE-epsilon4) genotype. Combined effects of stress and APOE status on memory and cortisol in humans have not been studied.


METHODS
A semistructured interview with standardized scoring was used to measure stress level and univariate analysis of variance to assess effects of stress and APOE-epsilon4 status on memory and salivary cortisol in 91 nondemented subjects (mean age 78.8 years).


RESULTS
Low-stress subjects performed better than high-stress subjects on delayed recall of stories (p = .04), word lists (p = .02), and visual designs (p = .04). APOE-epsilon4-negative subjects obtained better scores than epsilon4-positive subjects on immediate (p = < .01) and delayed (p < .01) recall of visual designs. Significant stress by APOE-epsilon4 interaction effects on memory (p = .03) and cortisol (p < .01) resulted from consistently worse memory and higher cortisol concentrations in the high stress, epsilon4-positive group.


CONCLUSIONS
These findings are consistent with a model in which prolonged exposure of older, nondemented individuals to stress in the presence of an epsilon4 allele leads to memory decline. Further studies will assess whether stress and APOE-epsilon4 interact to increase the risk of developing Alzheimer's disease.
Peavy
Guerry M
GM
Department of Neurosciences, University of California, San Diego, California, USA. gpeavy@ucsd.edu
Lange
Kelly L
KL
Salmon
David P
DP
Patterson
Thomas L
TL
Goldman
Sherry
S
Gamst
Anthony C
AC
Mills
Paul J
PJ
Khandrika
Srikrishna
S
Galasko
Douglas
D
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001057:Apolipoproteins E / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005838:Genotype; D015577:Geriatric Assessment; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D008568:Memory / Q000502:physiology*; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012463:Saliva / Q000378:metabolism; D013315:Stress, Psychological / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology
D001057:Apolipoproteins E; D006854:Hydrocortisone