Differences in Total Brain Volume between Sexes in a Cognitively Unimpaired Elderly Population

Abstract

Although a large number of studies have shown brain volumetric differences between men and women, only a few investigations have analyzed brain tissue volumes in representative samples of the general elderly population. We investigated differences in gray matter (GM) volumes, white matter (WM) volumes, and intracranial volumes (ICVs) between the sexes in individuals older than 66 years using structural magnetic resonance imaging (MRI). METHODS: Using FreeSurfer version 5.3, we obtained the ICVs and GM and WM volumes from the MRI datasets of 84 men and 92 women. To correct for interindividual variations in ICV, GM and WM volumes were adjusted with a method using the residuals of a least-square-derived linear regression between raw volumes and ICVs. We then performed an analysis of covariance comparing men and women, including age and years of schooling as confounding factors. RESULTS: Women had a lower socioeconomic status overall and fewer years of schooling than men. The comparison of unadjusted brain volumes showed larger GM and WM volumes in men. After the ICV correction, the adjusted volumes of GM and WM were larger in women. CONCLUSION: After the ICV correction and taking into account differences in socioeconomic status and years of schooling, our results confirm previous findings of proportionally larger GM in women, as well as larger WM volumes. These results in an elderly population indicate that brain volumetric differences between sexes persist throughout the aging process. Additional studies combining MRI and other biomarkers to identify the hormonal and molecular bases influencing such differences are warranted.

Central arterial stiffness, brain white matter hyperintensity and total brain volume across the adult lifespan

“…However, normalized brain volumetric measurements with ICV were larger in women (Table 1). These observations are consistent with previous studies of sex-related brain volume differences [43–45] and suggest that women may have higher brain tissue density than men [46].…”

Shared molecular genetic factors influence subcortical brain morphometry and Parkinson’s disease risk

“…We obtained GWAS summary statistics from the ENGIMA-CHARGE consortium through the corresponding data application. GWAS for the UK Biobank and ABCD cohorts were performed using a linear mixed model accounting for genotyping array, sex, age, sex*age, age 2 , sex*age 2 , and the first 20 genetic principal components to adjust further for the potential effects arising from sex differences 73 , fluctuations in brain volumes due to age differences among individuals 74 , and population stratification. Subcortical brain volumes GWAS were adjusted for the effects of total ICV.…”

Sex difference in the associations of socioeconomic status, cognitive function and brain volume with dementia in old adults: Findings from the OASIS study

“…A previous study demonstrated the presence of significant differences in neuroanatomical structure volumes between men and women in a population sample of participants above 66 years of age. 27 It revealed that the adjusted gray and whiter matter volume was larger in women. Since the total brain volume is calculated as the sum of the gray and white matter volumes, this finding is consistent with our analysis that average nWBV was higher in women than in men.…”

“…Consistent with this study, it has been shown to be larger in women than in men, although uncorrected brain volume measurements, such as gray matter and white matter are smaller in women. 27 As the strength of its association with dementia is the same in both men and women, similar to MMSE, the higher average nWBV in women may be the contributor to lower All rights reserved. No reuse allowed without permission.…”