Science

Sujung Yoon, Hanbyul Cho, Jungyoon Kim, Do-Wan Lee, Geon Ha Kim, Young Sun Hong, Sohyeon Moon, & Shinwon Park, & Sunho Lee, & Suji Lee, & Sujin Bae, Donald C. Simonson, In Kyoon Lyoo

Aims/hypothesis
Overweight and obesity may significantly worsen glycaemic and metabolic control in type 2 diabetes. However, little is known about the effects of overweight and obesity on the brains of people with type 2 diabetes. Here, we investigate whether the presence of overweight or obesity influences the brain and cognitive functions during early stage type 2 diabetes.
Methods
This study attempted to uncouple the effects of overweight/obesity from those of type 2 diabetes on brain structures and cognition. Overweight/obese participants with type 2 diabetes had more severe and progressive abnormalities in their brain structures and cognition during early stage type 2 diabetes compared with participants with normal weight. Relationships between each of these measures and disease duration were also examined.
Results
Global mean cortical thickness was lower in the overweight/obese type 2 diabetes group than in the normal-weight type 2 diabetes group (z = −2.96, p for group effect = 0.003). A negative correlation was observed between disease duration and global mean white matter integrity (z = 2.42, p for interaction = 0.02) in the overweight/obese type 2 diabetes group, but not in the normal-weight type 2 diabetes group. Overweight/obese individuals with type 2 diabetes showed a decrease in psychomotor speed performance related to disease duration (z = −2.12, p for interaction = 0.03), while normal-weight participants did not.
Conclusions/interpretation
The current study attempted to uncouple the effects of overweight/obesity from those of type 2 diabetes on brain structures and cognition. Overweight/ obese participants with type 2 diabetes had more severe and progressive abnormalities in brain structures and cognition during early stage type 2 diabetes compared with normal- weight participants.