Obesity linked to brain changes in type 2 diabetes
medwireNews: Patients with type 2 diabetes who are overweight or obese have more severe abnormalities in brain structure and cognition than those who are of normal weight, study results suggest.
These findings “highlight the need for early intervention aimed to reduce risk factors for overweight or obesity in type 2 diabetic individuals to preserve their brain structure and cognitive function,” say the researchers.
In Kyoon Lyoo (Ewha Womans University, Seoul, South Korea) and colleagues found that global mean cortical thickness was significantly lower among 50 overweight/obese patients (body mass index [BMI]≥25 kg/m2) with type 2 diabetes relative to 50 normal-weight patients (BMI<25 kg/m2) with type 2 diabetes (z score=–2.96).
The team notes that interactions between weight status and brain changes were specific to certain regions of the brain; participants in the overweight/obese type 2 diabetes group had a significantly thinner cortex in the temporal and motor regions compared with those in the normal-weight type 2 diabetes group (z scores= –4.36 and –2.91, respectively).
“[R]egion-specific interaction effects were primarily observed in the temporal region, indicating that the temporal lobe is vulnerable to the combined effects of overweight/obesity and type 2 diabetes,” explain the authors.
Using a predictive model to estimate whether disease duration has differential effects on brain and cognitive measures over time, Lyoo and colleagues identified a gradual decrease in white matter integrity from baseline to 6 years after diabetes among overweight/obese patients with type 2 diabetes, but not in the normal-weight diabetes group.
And overweight/obese patients with diabetes had a greater decrease in psychomotor speed performance with increasing disease duration than normal-weight patients, but there was no significant interaction between weight status and disease duration for memory or executive function.
Taken together, these findings “suggest that weight status may play additive roles in type 2 diabetes-related brain and cognitive alterations,” say Lyoo and colleagues in Diabetologia.
However, the researchers concede that “it is noteworthy that the current study did not recruit overweight/obese individuals without type 2 diabetes.”
“Therefore, we could not determine the potential effects of overweight/obesity that are completely independent of type 2 diabetes on metabolic, brain and cognitive measures,” they caution.
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