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.
Coffey
C E
CE
Department of Psychiatry, Henry Ford Health System, Detroit, MI 48202, USA. ecoffey1@hfhs.org
Saxton
J A
JA
Ratcliff
G
G
Bryan
R N
RN
Lucke
J F
JF
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