Cognitive decline and survival in Alzheimer's disease according to education level.
OBJECTIVE
We tested the hypothesis that a higher education level is associated with faster cognitive decline and lower survival in a cohort of 670 Alzheimer's disease patients, followed for 3.5 years at the Lille-Bailleul memory centre.


METHODS
The patients were categorized in 3 groups according to educational levels: low (<or=8 years), intermediate (9-12 years) and high (>12 years). Cognitive function was measured with the Mini Mental State Examination (MMSE) and the Mattis Dementia Rating Scale (DRS). Survival was analyzed with a Cox model. Analyses were adjusted for age, sex, cholinesterase inhibitor treatment, diabetes, hypertension, visible vascular lesions on MRI, baseline DRS and MMSE.


RESULTS
The adjusted mixed random model showed that MMSE declined faster for patients with high and intermediate educational levels compared with those with a low educational level (p < 0.0001). The mean annually adjusted DRS decline was highest for the groups with the most education (p = 0.05). The mortality risk was not higher in the better-educated groups (high vs. low: RR = 0.84; 95% CI = 0.35-1.99, intermediate vs. low: RR = 0.82; 95% CI = 0.41-1.63).


CONCLUSIONS
In our cohort, highly educated patients had a faster cognitive decline than less educated patients but similar mortality rates. Our findings support the cognitive reserve hypothesis.
Bruandet
A
A
INSERM, U744, Institut Pasteur de Lille, Université de Lille 2, Lille, France.
Richard
F
F
Bombois
S
S
Maurage
C A
CA
Masse
I
I
Amouyel
P
P
Pasquier
F
F
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology*; D001284:Atrophy / Q000453:epidemiology / Q000473:pathology; D001921:Brain / Q000473:pathology; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D004522:Educational Status; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D011788:Quality of Life / Q000523:psychology*; D011795:Surveys and Questionnaires