Diabetes and cardiovascular disease increase dementia risk

People with at least two conditions out of type 2 diabetes, heart disease and stroke have double the risk of developing dementia, according to new research from the Karolinska Institutet in Sweden.

Type 2 diabetes, heart diseases (ischemic heart disease, heart failure or atrial fibrillation) and stroke – known as cardiometabolic diseases – are some of the main risk factors for dementia.

‘Few studies have examined how the risk of dementia is affected by having more than one of these diseases simultaneously, so that’s what we wanted to examine in our study,’ said Abigail Dove, doctoral student at the Aging Research Centre, part of the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet.

The researchers extracted data from the Swedish National Study on Aging and Care on a total of 2,500 healthy, dementia-free individuals over the age of 60 living on Kungsholmen in Stockholm.

At the start of the study, the incidence of cardiometabolic diseases was assessed through medical records and clinical investigation. The participants were then followed for twelve years with medical examinations and cognitive tests in order to monitor changes in cognitive ability and the development of dementia.

The presence of more than one cardiometabolic disease accelerated the speed of cognitive decline and doubled the risk of cognitive impairment and dementia, expediting their development by two years. The magnitude of the risk was increased with a greater number of diseases.

‘In our study, the combinations of diabetes/heart disease and diabetes/heart disease/stroke were the most damaging to cognitive function,’ says Dove.

However, individuals who had just one cardiometabolic disease did not display a significantly higher risk of dementia.

‘This is good news. The study shows that the risk only increases once someone has at least two of the diseases, so it’s possible that dementia can be averted by preventing the development of a second disease,’ said the researchers.

The correlation between cardiometabolic diseases and the risk for dementia was stronger in the participants who were under 78 years old.

As a result, the authors suggest that cardiometabolic disease prevention efforts focus on middle age, since the risk of cognitive failure and dementia is higher among those who develop a cardiometabolic disease earlier in life.

Photo by Robina Weermeijer