Diabetes Forecast

Weight Worsens Cognitive Decline in People With Type 2 Diabetes

By Matt McMillen , , ,

Photo Credit: Fukurou/BigStock

What to Know

Past studies have shown that type 2 diabetes increases the risk of dementia and speeds up the progression of memory loss, difficulty concentrating, and other types of cognitive impairment. Scientists don’t know why diabetes has this effect, though they speculate that the brain may be harmed by insulin resistance, poor control of blood glucose, and inflammation. This study investigated whether excess weight may worsen the impact of type 2 diabetes on the brain in the disease’s early stages.

The Study

Korean researchers recruited participants for three groups: 50 overweight or obese people with type 2 diabetes, 50 people with type 2 diabetes whose weight was in the normal range, and 50 normal-weight people who did not have diabetes. The volunteers ranged in age from 30 to 60. Those with diabetes had been diagnosed within the previous five years. Each participant underwent a physical exam, an MRI brain scan, and a battery of cognitive tests at the start of the study and again a year later.

The Results

People with type 2 diabetes fared worse for a variety of reasons. Parts of the cerebral cortex, which controls language, reasoning, and other essential brain functions, were noticeably thinner in participants with diabetes, particularly those who were overweight or obese, than in those who did not have diabetes. Excess weight was linked to faster deterioration of white matter, a type of brain tissue that helps connect different parts of the brain. And the longer that overweight and obese participants had diabetes, the greater the white matter deterioration. People with type 2 diabetes also performed worse on memory and brain-processing tests than those who did not have diabetes. Among participants with diabetes, brain processing slowed more significantly in those who were overweight or obese.


To protect your brain, don’t delay weight loss once you’ve been diagnosed with diabetes. Brain impairment can occur in the early stages of type 2 diabetes, and excess weight appears to amplify the problem. This study did not include overweight or obese people without diabetes; doing so could have affected the researchers’ conclusions. Glucose-lowering medications, some of whichhave positive effects on the brain, may also have influenced the study results.

Brain Changes in Overweight/Obese and Normal-Weight Adults with Type 2 Diabetes Mellitus.” 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. Diabetologia, July2017; 60(7): 1207-1217

The information on this screen does not take the place of care from your doctor or other health care provider. If you have general questions about diabetes or diabetes-related research, e-mail askada@diabetes.org or call 1-800-DIABETES (800-342-2382).



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