Sex dimorphism in gray/white matter volume and diffusion tensor during normal aging

• Published in: NMR in biomedicine 2010-06, Vol.23 (5), p.446-458
• Main Authors: Abe, Osamu, Yamasue, Hidenori, Yamada, Haruyasu, Masutani, Yoshitaka, Kabasawa, Hiroyuki, Sasaki, Hiroki, Takei, Kunio, Suga, Motomu, Kasai, Kiyoto, Aoki, Shigeki, Ohtomo, Kuni
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aging; Anisotropy; Brain - growth & development; central nervous system; Diffusion; Diffusion Magnetic Resonance Imaging - methods; diffusion tensor imaging; Female; Humans; magnetic resonance imaging; Male; Middle Aged; Organ Size; Regression Analysis; sex; Sex Characteristics; voxel-based morphometry; Young Adult
• ISSN: 0952-3480; 1099-1492
• DOI: 10.1002/nbm.1479

The purpose of this study is to elucidate sex differences in global and regional gray/white matter volume, mean diffusivity (MD), and fractional anisotropy (FA) during normal aging using voxel‐based analysis. We studied 245 healthy right‐handed subjects with a wide range of ages (115 women, 22–70 years; 130 men, 21–71 years). Regarding global effects, inclusion of a quadratic age term improved the fit to data for white matter fraction and MD, but not for global gray matter volume/fraction or FA. Regarding regional effects, we found anterior‐dominant volume loss, FA decrease predominantly in the anterior white matter, and MD increase predominantly in perisylvian regions and periventricular white matter against age for both sexes. Compared with women, we found a steeper FA decline for men in the right inferior fronto‐temporal areas, extending to the anterior cingulate cortex, and an accelerated MD increase for men in the bilateral frontal, temporal, and parietal areas. There was no area in which interaction of sex with age was significant for regional volume, or in which a steeper FA decline or accelerated MD increase for women was significant. Our results provide strong evidence of sex dimorphism in global and focal diffusion characteristics during normal aging. Copyright © 2010 John Wiley & Sons, Ltd. Although we found a steeper FA decline for men in the right inferior fronto‐temporal areas, extending to the anterior cingulate cortex, and an accelerated MD increase for men in the bilateral frontal, temporal, and parietal areas, compared with women, there was no local area showing significant interaction of sex with age for brain volume. Diffusion tensor characteristics in the human brain appear to be sensitive to the effects of both age and sex.