White matter integrity disparities between normal-weight and overweight/obese adolescents: an automated fiber quantification tractography study

Obese adults have been shown to have poorer white brain matter integrity relative to normal-weight peers, but few studies have tested whether white matter integrity is compromised in overweight and obese adolescents. Also, it is unclear if age interacts with body mass to affect white matter integrity in adolescents. We used Automated Fiber Quantification, a tractography method, to compare fractional anisotropy between normal-weight and overweight/obese adolescents in the corpus callosum, corticospinal tract, cingulum, inferior fronto-occipital fasciculus, and uncinate fasciculus. Further, we tested whether any differences were moderated by age. Forty-seven normal-weight and forty overweight/obese adolescents were scanned using a diffusion tensor imaging (DTI) scan sequence. Overweight/obese compared to normal-weight adolescents had decreased white matter integrity in the superior frontal corpus callosum, left and right uncinate fasciculi, left inferior fronto-occipital fasciculus, and left corticospinal tract, which may be related to heightened reward processing. Overweight/obese compared to normal-weight adolescents had increased white matter integrity in the orbital and anterior frontal corpus callosum, right inferior fronto-occipital fasciculus, left cingulum, and left corticospinal tract, which may be related to heightened attentional processing. As age increased, six tracts showed poorer white matter integrity as body mass index percentile (BMI%) increased, but three tracts showed greater white matter integrity as BMI% increased. Future research examining associations between white matter integrity and neural indices of food-related reward and attention are needed to clarify the functional significance of white matter integrity discrepancies between normal-weight and overweight/obese adolescents.