Evaluating effects of sex and age on white matter microstructural alterations in alcohol use disorder: A diffusion tensor imaging study

Background Alterations in white matter microstructure associated with chronic alcohol use have been demonstrated in previous diffusion tensor imaging (DTI) research. However, there is conflicting evidence as to whether such differences are influenced by an individual's biological sex. The purpose of the present study was to investigate the prevalence of sex differences in the white matter microstructure of the brains of individuals with alcohol use disorder (AUD) and healthy controls. Methods One hundred participants with AUD (38 female, aged 21 to 68) participating in the National Institute on Alcohol Abuse and Alcoholism's inpatient treatment program and 98 healthy control participants (52 female) underwent a diffusion-weighted scan. Images collected were processed for each subject individually, and voxelwise, tract-based spatial statistics analysis was conducted to test for differences in the DTI measures of fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD). Results A 2-way, between-subjects ANCOVA that tested for differences by group and sex revealed widespread differences between AUD and control subjects, but no interaction between group and sex. Additional analyses exploring demographic and alcohol use variables showed significant impacts of age on white matter microstructure that were more pronounced in individuals with AUD. Plots of FA by age, sex, and group in major white matter tracts suggest a need to explore higher order interactions in larger samples. Conclusions These results bolster recent findings of similar microstructural properties in men and women with AUD but provide a rationale for the consideration of age when investigating the impacts of chronic alcohol use on the brain's white matter.