Overweight and obesity are associated with functional and structural alterations in the brain, but how these associations change across critical developmental periods remains unknown. Here, we examined the relationship between age, body mass index (BMI) and cortical thickness (CT) in healthy adolescents (n = 70; 14–19 y) and adults (n = 75; 25–45 y). We also examined the relationship between adiposity, impulsivity, measured by delay discounting (DD), and CT of the inferior frontal gyrus (IFG), a region key to impulse control. A significant age-by-BMI interaction was observed in both adolescents and adults; however, the direction of this relationship differed between age groups. In adolescents, increased age-adjusted BMI Z-score attenuated age-related CT reductions globally and in frontal, temporal and occipital regions. In adults, increased BMI augmented age-related CT reductions, both globally and in bilateral parietal cortex. Although DD was unrelated to adiposity in both groups, increased DD and adiposity were both associated with reduced IFG thickness in adolescents and adults. Our findings suggest that the known age effects on CT in adolescence and adulthood are moderated by adiposity. The association between weight, cortical development and its functional implications would suggest that future studies of adolescent and adult brain development take adiposity into account.

超重和肥胖与大脑功能和结构的改变有关，但这些关联在关键发育时期如何变化仍不清楚。在这里，我们研究了健康青少年（n = 70；14-19 岁）和成人（n = 75；25-45 岁）的年龄、体重指数 (BMI) 和皮质厚度 (CT) 之间的关系。我们还研究了肥胖、冲动性（通过延迟贴现 (DD) 测量）和额下回 (IFG)（冲动控制的关键区域）CT 之间的关系。在青少年和成人中都观察到了显着的年龄与体重指数交互作用；然而，这种关系的方向因年龄组而异。在青少年中，年龄调整后的 BMI Z 分数的增加减弱了整体以及额叶、颞叶和枕骨区域与年龄相关的 CT 降低。在成年人中，体重指数的增加增加了与年龄相关的 CT 降低，无论是整体还是双侧顶叶皮层。尽管两组的 DD 均与肥胖无关，但青少年和成人中 DD 和肥胖的增加均与 IFG 厚度的减少相关。我们的研究结果表明，已知的年龄对青春期和成年期 CT 的影响受到肥胖的影响。体重、皮质发育及其功能影响之间的关联表明，未来对青少年和成人大脑发育的研究应考虑肥胖因素。