New research has found that people with type 2 diabetes, especially those who are overweight or obese, have thinner grey matter in several areas of the brain. This has to be read together with results of earlier research which has linked type 2 diabetes and memory loss.
The affected brain regions are related to memory, executive function, movement generation and visual information processing, according to the study’s senior author, Dr In Kyoon Lyoo, director of the Ewha University Brain Institute in Seoul, South Korea. The study was released last Thursday in the journal Diabetologia, reports Serena Gordon on WebMD News from HealthDay.
Given that obesity leads to increased risk of type 2 diabetes, metabolic dysfunction and is also associated with brain alterations independently, the new research aimed to investigate whether overweight/obesity influenced brain structure and cognitive function in individuals with early stage of type 2 diabetes.
The study included: 50 overweight or obese people with type 2 diabetes; 50 normal-weight people with type 2 diabetes, and 50 normal-weight people without diabetes. The Korean study volunteers were between 30 and 60 years old. Those with diabetes had it for five years or less, and were attempting lifestyle modifications and/or taking oral medication to lower blood sugar levels. No one was taking insulin.
The normal-weight group with type 2 diabetes had slightly better blood sugar control – a haemoglobin A1C level of 7%. The overweight folks with type 2 diabetes had haemoglobin A1C levels of 7.3%. Haemoglobin A1C is a two- to three- month estimate of average blood sugar levels. The American Diabetes Association generally recommends an A1C of 7% or less.
All study participants underwent MRI brain scans and tests to measure memory and thinking skills. Cortical thickness was decreased in several regions of the diabetic brains. Further thinning of the temporal lobes found in overweight/obese individuals with type 2 diabetes suggests that these regions are specifically vulnerable to combined effects of obesity and type 2 diabetes.
Though Dr Lyoo said this study alone cannot tease out whether the effect is from excess weight or diabetes or both, it did find that the longer someone had diabetes, the more likely they were to have brain changes. Factors such as insulin resistance, inflammation and poor blood sugar management might bring about the changes.
Memory and thinking skills were decreased in people with diabetes – regardless of weight – compared to the normal-weight people without type 2 diabetes, the study found. Because the study only included an Asian population, Dr Lyoo said it is not clear if these effects would apply to other populations. He also said it is not known if these effects occur in people with type 1 diabetes, the less common form of diabetes. Good blood-sugar management would probably help slow down or prevent these diabetes- or obesity-related brain changes. In short, the latest study also reiterates that diabetes, if left unchecked, wreaks havoc with health.
