Effects of age and gender on neuroanatomical volumes

To investigate age-related differences, gender differences, and age-by-gender interactions on the volumes of 18 neuroanatomical structures, with a large sample at a single institution.

A total of 861 normal subjects (mean age = 56.1 ± 9.8 years, age range = 24.0-84.8 years) were included in this study. All subjects were scanned at 3.0 T. Measurement of the 18 neuroanatomical volumes was performed with FreeSurfer v. 4.5. Differences in volumes of neuroanatomical structures were tested using analysis of covariance with intracranial volume-normalized volume as the dependent variable, and independent variables of age, sex, age × sex, age × age, age × age × sex, and scanner. Nonsignificant higher-order terms were removed sequentially from the model. A P value of < 0.0028 (=0.5/18) was considered to indicate a statistically significant difference.

All neuroanatomical volumes, except for the caudate nucleus, pallidum, and 4th ventricle, were significantly related to age (linearly or quadratically). Significant gender differences were found in all neuroanatomical volumes, except for cerebral white matter, cerebellar cortex, caudate nucleus, and amygdala. No neuroanatomical volume showed a significant interaction between age (age × age) and gender.

Our results showed age and gender effects on neuroanatomical volumes, and indicate no gender difference in the aging process of neuroanatomical volumes.