APOE-epsilon4, depressive symptoms, and cognitive decline in Chinese older adults: Singapore Longitudinal Aging Studies.
BACKGROUND
The precise relationship between depression and cognitive decline in older adults is unclear. We investigated the influence of apolipoprotein E (APOE)-epsilon4 genotype in modulating the effect of depressive symptoms on cognitive decline.


METHODS
Prospective cohort study of 1,487 cognitively high-functioning Chinese older adults. Depressive symptoms (Geriatric Depression Scale score >/=5) and Mini-Mental State Examination (MMSE) were assessed at baseline, and cognitive decline (at least 1-point drop in MMSE) at 1-2 years after baseline.


RESULTS
There was no significant difference in cognitive decline between depressed (32.9%) and nondepressed (31.5%) participants in the whole sample or among non-APOE-epsilon4 carriers. Among APOE-epsilon4 carriers, depressed participants showed more cognitive decline (40.0%) than their nondepressed counterparts (28.6%), odds ratio = 2.89, 95% confidence interval: 1.03-8.12; p = .04, after controlling for age, gender, education, vascular risk factors/events, smoking, alcohol drinking, physical functioning, subjective memory complaint, length of follow-up, and baseline MMSE scores (p for interaction = .03).


CONCLUSIONS
Our study suggests that the presence of the APOE-epsilon4 allele significantly enhanced the risk of cognitive decline associated with depressive symptoms. This finding should be independently replicated in future studies.
Niti
Mathew
M
Gerontological Research Programme, National University of Singapore, 5 Lower Kent Ridge Road, Singapore 119074.
Yap
Keng-Bee
KB
Kua
Ee-Heok
EH
Ng
Tze-Pin
TP
D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics*; D000483:Alleles; D053327:Apolipoprotein E4 / Q000235:genetics* / Q000378:metabolism; D044466:Asian People; D002681:China / Q000453:epidemiology; D003072:Cognition Disorders / Q000208:ethnology* / Q000235:genetics*; D015331:Cohort Studies; D003866:Depressive Disorder / Q000208:ethnology* / Q000235:genetics*; D018450:Disease Progression; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D015577:Geriatric Assessment; D006579:Heterozygote; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D017678:Sex Distribution; D012846:Singapore / Q000208:ethnology
D053327:Apolipoprotein E4