Researchers investigate why people with type 2 diabetes develop dementia

The research, presented at the Diabetes UK Professional Conference 2021, looked at ‘cardiometabolic factors’ – such as blood pressure, blood sugars and cholesterol levels – in people with type 2 diabetes over 20 years. Researchers identified changes in these factors during this period that were linked with developing dementia in later life.

Dementia, a group of conditions that affect the brain, causing memory loss and other changes to brain function, is more common in people with type 2 diabetes.

However, the reason why people with type 2 are more at risk hasn’t been clear.

High blood sugar levels, blood pressure and cholesterol in people with type 2 diabetes can damage blood vessels and lead to serious cardiovascular problems, such as heart attacks and strokes.

It has been suggested that these ‘cardiometabolic factors’ that are known to affect heart health might also affect brain health and could potentially play a role in the development of dementia in people with type 2 diabetes.

A team of researchers, led by Dr Eszter Vamos at Imperial College London, looked to see if the factors affecting heart health in people with type 2 diabetes could also impact their dementia risk.

They analysed figures from 227,580 people with type 2 diabetes over the age of 42 years, around 10% of whom went on to develop dementia.

The team examined the participants’ medical history across the 20 years prior to their dementia diagnosis to look at changes in cardiometabolic factors and bodyweight and compared these to people who didn’t develop dementia.

Over the two decades of the study period, researchers noted changes in blood pressure between those who did and didn’t develop dementia.

People who developed dementia had higher blood pressure between 11-19 years before their dementia diagnosis, which reduced faster closer to their diagnosis, compared to those who didn’t develop dementia.

Weight loss starting at 11 years before a dementia diagnosis was found in people who developed the condition and this was higher than in those who did not develop the condition.

Blood sugar and cholesterol levels were also found to be generally higher across the entire 20-year period among people with type 2 diabetes who developed dementia, compared to those who did not.

Eating healthily, keeping active, reducing alcohol intake and stopping smoking are all advised to help everyone reduce their risk of dementia

Researchers said these findings suggested that by monitoring cardiometabolic factors and managing blood sugar, blood pressure, cholesterol and bodyweight, people with type 2 diabetes could be supported to lower their risk of dementia.

Study lead Dr Eszter Vamos said: “Our results emphasise the importance of carefully managing cardiometabolic factors such as blood pressure, cholesterol and glucose levels early on, for people with type 2 diabetes.

“While this study cannot confirm causal associations, these results show that blood pressure and other cardiometabolic factors could be contributing to dementia development up to two decades before diagnosis.”

The researchers plan to follow-up their studies by looking at whether diabetes-related complications such as eye and kidney problems could be linked to dementia risk. The team will also examine whether risk factors for type 2 diabetes that cannot be controlled – such as age and ethnicity – could work alongside cardiometabolic factors to determine dementia risk.