Background: Little is known about the effect of sex on age-related cha
nges in brain structure. Methods: Quantitative magnetic resonance imag
ing of the brain was performed in 330 elderly (age range, 66-96 years)
volunteers living independently in the community, all of whom were pa
rticipants in the Cardiovascular Health Study. Blinded measurements of
global and regional brain size were made from T-1-weighted axial imag
es by means of computer-assisted edge detection and trace methods. Hig
h measurement reliabilities were obtained. Results: Age-specific chang
es in brain size were significantly greater in men than women for the
peripheral (sulcal) cerebrospinal fluid volume, the lateral (sylvian)
fissure cerebrospinal fluid volume, and the parietooccipital region ar
ea. Main effects of age were observed for all the remaining brain regi
ons examined (cerebral hemisphere volume, frontal region area, temporo
parietal region area, lateral ventricular volume, and third ventricle
volume), but these effects were similar in men and women. Asymmetries
in brain structures were not affected by aging in either sex. Conclusi
ons: Our results are generally consistent with the few published studi
es on sex differences in brain aging and suggest that, for at least so
me structures, aging effects may be more apparent in men than women. T
he neurobiological bases and functional correlates of these sex differ
ences require further investigation.