Patients with type 2 diabetes mellitus (T2DM) with overweight or obesity were more likely to show severe and progressive brain function and cognition abnormalities compared with patients at a normal weight, according to recent research published in Diabetologia.
“This study showed that the concurrent presence of overweight/obesity was associated with cortical atrophy, disrupted white matter integrity and cognitive dysfunction in early stage [T2DM],” In Kyoon Lyoo, MD, PhD, from the Ewha Brain Institute and the Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea, and fellow researchers wrote.
“An increased awareness of overweight/obesity-related risk is necessary to prevent and manage [T2DM]-related brain atrophy and cognitive dysfunction from early stage [T2DM] onward.”
The researchers studied 50 patients with overweight or obesity who had been diagnosed with T2DM for fewer than 5 years and compared them with an age-, sex-, and disease duration-matched cohort of 50 patients at a normal weight with T2DM and 50 individuals in a control group who were at a normal weight.
Patients were between 30 and 60 years of age, with body mass index (BMI) cut-offs for overweight and obesity at 25 to 29.9 kg/m2 and ≥30 kg/m2, respectively.
All patient groups underwent brain imaging that included global mean cortical thickness measurements and global mean fractional anisotropy of the whole brain white matter skeleton. Cognitive tests were also administered to assess memory, executive function, and psychomotor speed.
The researchers found a lower global mean cortical thickness in patients in the overweight and obese T2DM group (z, −2.96) compared with patients in the normal weight T2DM group (P for group effect =.003). There was a negative association between disease duration and global white matter integrity in the overweight and obese T2DM group (z, 2.42) compared with the normal weight T2DM group (P for interaction =.02), as well as a decrease in psychomotor speed in the overweight and obese T2DM group (z, −2.12) not seen in the T2DM group at a normal weight (P for interaction =.03).
The researchers recommended longitudinal follow-up for patients with overweight or obesity with T2DM to determine any long-term effects of impaired glucose tolerance on brain function and cognition.
“Our results suggest that a relationship exists between disease duration and metabolic measures in each diabetic group (classified according to BMI),” the researchers wrote. “However, as there was no information on fasting insulin and C-peptide levels in the normal-weight control group, differences in metabolic measures between the type 2 [diabetes] and control groups could not be determined in the present study.”
Yoon S, Cho H, Kim J, et al. Brain changes in overweight/obese and normal-weight adults with type 2 diabetes mellitus [published online April 27, 2017]. Diabetologia. doi:10.1007/s00125-017-4266-7