Educational attainment and hippocampal atrophy in the Alzheimer's disease neuroimaging initiative cohort.
BACKGROUND
Subjects with higher cognitive reserve (CR) may be at a lower risk for Alzheimer's disease (AD), but the neural mechanisms underlying this are not known. Hippocampal volume loss is an early event in AD that triggers cognitive decline.


METHODS
Regression analyses of the effects of education on MRI-measured baseline HV in 675 subjects (201 normal, 329 with mild cognitive impairment (MCI), and 146 subjects with mild AD), adjusting for age, gender, APOE ɛ4 status and intracranial volume (ICV). Subjects were derived from the Alzheimer's Disease Neuroimaging Initiative (ADNI), a large US national biomarker study.


RESULTS
The association between higher education and larger HV was significant in AD (P=0.014) but not in cognitively normal or MCI subjects. In AD, HV was about 8% larger in a person with 20 years of education relative to someone with 6 years of education. There was also a trend for the interaction between education and APOE ɛ4 to be significant in AD (P=0.056).


CONCLUSIONS
A potential protective association between higher education and lower hippocampal atrophy in patients with AD appears consistent with prior epidemiologic data linking higher education levels with lower rates of incident dementia. Longitudinal studies are warranted to confirm these findings.
Department of psychiatry, neurocognitive disorders program, DUMC-3018, Duke University Medical Center, 27708 Durham, NC, United States; Duke Institute for Brain Sciences, 27708 Durham, NC, United States. Electronic address: yss4@duke.edu.
Katie S
KS
Shpanskaya
Department of radiology, Duke University Medical Center, 27708 Durham, NC, United States.
Kingshuk Roy
KR
Choudhury
Department of radiology, Duke University Medical Center, 27708 Durham, NC, United States.
Christopher
C
Hostage
Department of psychiatry, neurocognitive disorders program, DUMC-3018, Duke University Medical Center, 27708 Durham, NC, United States; Duke Institute for Brain Sciences, 27708 Durham, NC, United States.
Kelly R
KR
Murphy
Department of radiology, Duke University Medical Center, 27708 Durham, NC, United States.
Jeffrey R
JR
Petrella
Department of psychiatry, neurocognitive disorders program, DUMC-3018, Duke University Medical Center, 27708 Durham, NC, United States; Duke Institute for Brain Sciences, 27708 Durham, NC, United States.
P Murali
PM
Doraiswamy
D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000473:pathology*; D001284:Atrophy; D060825:Cognitive Dysfunction / Q000453:epidemiology* / Q000473:pathology*; D058245:Cognitive Reserve; D015897:Comorbidity; D003704:Dementia / Q000453:epidemiology* / Q000473:pathology; D004522:Educational Status; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
Alzheimer's; Cognitive reserve; Education; Hippocampal volume