Diabetes and Heart Disease Sharply Increase the Risk of Developing Dementia

You can sharply reduce your chances of suffering from dementia if you take steps to avoid contracting more than one of these diseases: type 2 diabetes, heart disease, and stroke.

That is the message from a Swedish study that finds you are at double the risk of developing dementia if you have at least two of those ailments, which are known as cardiometabolic diseases.

Earlier findings have shown that type 2 diabetes, stroke, and heart disease—such as heart failure, ischemic heart disease, or atrial fibrillation—are among the leading risk factors for developing dementia. Those projects, however, failed to examine how suffering from more than one of those three cardiometabolic diseases affects the risk of dementia, notes Abigail Dove, a doctoral student at the Aging Research Centre, which is part of the Department of Neurobiology, Care Sciences and Society at the Karolinska Institutet in Sweden.

Now this extensive study, of which Dove was the lead author, takes those findings a big step further by concluding that it is only when people suffer from more than one of those diseases that the threat to developing dementia becomes significant.

Develops slowly

Dementia takes place slowly over decades, the study authors explain. It first shows itself as a gradual decline in brain function that presents itself only in cognitive tests. Later it degenerates into brain impairment in which people will notice that their memories are failing, but they are still able to take care of themselves.

Finally, the condition develops into full dementia.

Study covered 12 years

To reach their conclusions, the researchers examined statistics on 2,500 people from the Swedish National Study on Aging and Care. They were all people aged over 60 who were free of dementia. At the outset of the study, the number of people suffering from cardiometabolic diseases (type 2 diabetes, heart disease, and stroke) was gathered through clinical investigation and medical records.

The participants in the study were then followed for 12 years during which time brain tests and medical examinations were conducted in order to monitor the development of dementia and cognitive ability.

Brain function declined

At the end of the study the researchers concluded that the presence of more than one cardiometabolic disease caused the speed of brain functions to decline. It also doubled the risk of developing brain impairment and dementia, speeding up the process by two years.

The more cardiometabolic diseases that the person suffered, the greater was the risk of developing dementia.

In the study the most damaging impact on brain function was the combination of heart disease/diabetes as well as stroke/heart disease/diabetes, Dove says.

Prevention of second disease vital

Those who had only one cardiometabolic disease failed to show any significantly higher risks of developing dementia.

This finding is good news, Dove says. It shows that the risk is greater only when a person has at least two of the cardiometabolic diseases. It is likely, therefore, that dementia can be avoided if you have one of the diseases by taking measures to prevent the development of a second or third cardiometabolic disease.

Should focus on middle aged

The link between cardiometabolic diseases and dementia risk was stronger in those participants who were under 78 years of age, the study found. As a result, we should focus on preventing cardiometabolic disease in middle age, Dove says.

The risk of decline in brain function and dementia seems to be higher among those who develop a cardiometabolic disease earlier in life, Dove explains.

Future studies

The researchers say they hope to learn more in future studies about the mechanism that drives the correlation between these diseases and dementia. Among the factors that could be examined are the effect of genetic factors and the use of brain imaging to learn the way in which cardiometabolic diseases can harm the brain.

The study appears in the journal Alzheimer’s & Dementia.