Prediabetes can be linked to poor brain health
People with prediabetes, whose blood sugar levels are higher than normal, may be at increased risk of cognitive decline and vascular dementia, according to a new study led by UCL researchers.
For this study, published in the journal Diabetes, Obesity and Metabolism, the researchers looked at data from the UK’s Biobank on an average of 58,000 people, aged 58, and found that people with higher than normal levels of blood sugar were 42% more likely to experience cognitive decline, and were 54% more likely to develop vascular dementia over an average of eight years (although absolute rates of both cognitive decline and dementia were low).
The associations remained true after other factors were considered – including age, smoking, BMI and whether or not the participants had cardiovascular disease.
People with prediabetes have higher blood sugar levels than usual, but not high enough to be diagnosed with type 2 diabetes. It means they are more at risk of developing diabetes. There are about five to seven million people with prediabetes in the UK alone.
The lead author of the research, Dr. Victoria Garfield (UCL Institute of Cardiovascular Science and UCL MRC Unit for Lifelong Health & Aging), said: “Our research shows a possible link between higher blood sugar levels – a condition often described as “Prediabetes” – and a greater risk of cognitive decline and vascular dementia. As an observational study, it cannot be proven that higher blood sugar levels cause deterioration in brain health. However, we believe that there is a potential connection that needs to be further investigated.”
Previous research has found a link between poorer cognitive outcomes and diabetes, but our study is the first to investigate how blood sugar levels, which are relatively high but do not yet constitute diabetes, can affect the health of our brains.
In the study, the researchers investigated how different blood sugar levels or glycemic conditions were associated with the performance of cognitive tests over time, diagnoses of dementia and brain structure as measured by brain MRI scans. Each of these measures was limited to smaller subsets of the Biobank sample (for example, only 18,809 participants had cognitive follow-up tests).
At recruitment, all Biobank participants in the UK underwent an HbA1c test, which had average blood sugar levels in the last two to three months. Participants were divided into five groups based on the results – “low-normal” blood sugar, normoglycemia (having a normal blood sugar), prediabetes, undiagnosed diabetes and diabetes.
The researchers used data from repeated assessments of visual memory to determine whether or not participants had cognitive decline. Although absolute rates of cognitive decline were low, people with prediabetes and diabetes had a similarly higher probability of cognitive decline – 42% and 39%, respectively.
Regarding the diagnosis of dementia, the researchers found that prediabetes was associated with a higher likelihood of vascular dementia, a common form of dementia caused by reduced blood flow to the brain, but not Alzheimer’s disease. Meanwhile, people with diabetes were three times more likely to develop vascular dementia, than people whose blood sugar levels were classified as normal, and more likely to develop Alzheimer’s disease.
Among 35,418 participants in the UK Biobank study who underwent brain MRI scans, the researchers found that prediabetes was somewhat associated with a smaller and stronger hippocampus associated with brain damage.
People with prediabetes can reduce their risk of developing type 2 diabetes by consuming a healthy and balanced diet, being more active and staying at a healthy weight. The best way to start a healthy lifestyle is with the help of the Dahna application, which offers you both daily menus inspired by the Mediterranean diet and physical video workouts with coach Diana Stejereanu. Download the app for free from the AppStore or Google Play!