Relation of education to brain size in normal aging: implications for the reserve hypothesis.
OBJECTIVE
To examine the relations between education and age-related changes in brain structure in a nonclinical sample of elderly adults.


BACKGROUND
Education may protect against cognitive decline in late life--an observation that has led to the "reserve" hypothesis of brain aging. Little is known, however, about the effect of education on age-related changes in brain structure.


METHODS
Quantitative MRI of the brain was performed in 320 elderly volunteers (age range, 66 to 90 years) living independently in the community (Mini-Mental State Examination scores > or =24), all of whom were participants in the Cardiovascular Health Study. Blinded measurements of global and regional brain size were made from T1-weighted axial images using computer-assisted edge detection and trace methodology. High measurement reliabilities were obtained.


RESULTS
Regression analyses (adjusting for the effects of intracranial size, sex, age, age-by-sex interactions, and potential confounders) revealed significant main effects of education on peripheral (sulcal) CSF volume-a marker of cortical atrophy. Each year of education was associated with an increase in peripheral CSF volume of 1.77 mL (p<0.03). As reported previously, main effects of age (but not education) were observed for all of the remaining brain regions examined, including cerebral hemisphere volume, frontal region area, temporoparietal region area, parieto-occipital region area, lateral (Sylvian) fissure volume, lateral ventricular volume, and third ventricle volume.


CONCLUSIONS
The authors' findings demonstrate a relation between education and age-related cortical atrophy in a nonclinical sample of elderly persons, and are consistent with the reserve hypothesis as well as with a small number of brain imaging studies in patients with dementia. The neurobiological basis and functional correlates of this education effect require additional investigation.
Department of Psychiatry, Henry Ford Health System, Detroit, MI 48202, USA. ecoffey1@hfhs.org
C E
CE
Coffey
J A
JA
Saxton
G
G
Ratcliff
R N
RN
Bryan
J F
JF
Lucke
D000368:Aged / Q000502:physiology* / Q000523:psychology; D000369:Aged, 80 and over / Q000502:physiology* / Q000523:psychology; D001284:Atrophy; D001921:Brain / Q000033:anatomy & histology* / Q000254:growth & development; D002540:Cerebral Cortex / Q000254:growth & development / Q000473:pathology / Q000502:physiology; D002555:Cerebrospinal Fluid; D004522:Educational Status; D005260:Female; D007839:Functional Laterality; D006304:Health Status; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008609:Mental Status Schedule; D012044:Regression Analysis; D012727:Sex Characteristics