Abstract Background Overwhelming evidence shows that obesity is associated with brain structural alterations in young adults. However, the specific sex related changes in obesity and their associated with crystallized intelligence still remained unclear. Methods In this study, 243 young adults with obesity and matched 243 lean individuals were enrolled from the Human Connectome Project Release S1200 dataset. Surface-based morphometry approach was adopted to investigate altered brain structures and related sex difference in young adults with obesity with three structural indicators including cortical thickness (CT), cortical surface area (CSA), and subcortical gray matter volume (GMV). Results While in female young adults, no significant difference of GMV of right amygdala was observed between obesity and lean groups, in male young adults, obesity group exhibited significantly higher GVM of right amygdala than lean group. Then, obesity male young adults showed significant correlation between GMV of right amygdala and crystallized intelligence, and such significant correlation was not found in obesity female young adults. Conclusions Obesity male young adults showed significantly higher GMV of right amygdala than lean male young adults, which was further associated with crystallized intelligence. Such findings were not observed in obesity female young adults. These findings suggested that the sex difference of adverse effect of obesity may be associated with the alterations of GMV of right amygdala.
He et al. (Sun,) studied this question.