SEX-DIFFERENCES IN BRAIN AGING - A QUANTITATIVE MAGNETIC-RESONANCE-IMAGING STUDY

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.