Obesity Affects Cognition in Type 2 Diabetes Patients

Being overweight and obese can be a risk factor for more severe and progressive abnormalities in brain structure and cognition in people with type 2 diabetes, Kyoon Lyoo, MD, PhD, and colleagues reported.

The researchers assessed relationships between measures of weight and brain structure and cognition in people with early-stage type 2 diabetes. The study “attempted to uncouple the effects of overweight/obesity from those of type 2 diabetes on brain structures and cognition,” the study’s authors wrote.
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The study included 50 people who were normal weight with type 2 diabetes and 50 people who were overweight or obese and were aged 30 to 60 years when diagnosed as having type 2 diabetes. Participants were classified as overweight if they had a BMI of 25 to 29.9, as obese if their BMI was greater than 30, and as normal weight if their BMI was 18.5 to 25. Participants in the study were matched for age and sex.

Using magnetic resonance imaging, the investigators evaluated white matter connectivity and the thickness of the cerebral cortex. In addition, participants underwent cognitive testing for memory, psychomotor speed, and executive function.

Results indicated lower global mean cortical thickness in individuals who were overweight/obese with type 2 diabetes, compared with individuals who were normal weight with type 2 diabetes. The temporal lobe seemed to be especially at risk for negative effects from the combination of being overweight/obese and having type 2 diabetes, the researchers noted.

Psychomotor speed performance was also decreased among overweight/obese individuals with type 2 diabetes, compared with individuals who were normal weight.

Although more research in this area is needed, this study suggests that the combination of being overweight/obese and having type 2 diabetes has a greater, negative effect on structural and functional aspects of the brain.

—Lauren LeBano

References

Yoon S, Cho H, Kim J, et al. Brain changes in overweight/obese and normal-weight adults with type 2 diabetes mellitus. Diabetologia. 2017. doi:10.1007/s00125-017-4266-7.