Type 2 diabetes affects memory and fluency in older people, new study suggests

by Barbara Hewitt on December 17, 2018

Type 2 diabetes is associated with a decline in brain function among older people with the condition over a five-year period, new research has found.

In particular it affects the verbal memory and fluency, according to the study by Australian experts at the University of Tasmania and Monash University in Melbourne.

Memory Loss

(By Lukiyanova Natalia frenta/Shutterstock.com)

However, contrary to previous studies, the decrease in brain volume often found in older people with type 2 diabetes was not found to be directly associated with cognitive decline during this time period.

Yet compared with people without type 2 diabetes, those with type 2 diabetes had evidence of greater brain atrophy at the beginning of the study.

Previous research has shown that type 2 diabetes can double the risk of dementia in older people, in this new study, Dr Michele Callisaya and colleagues aimed to discover whether type 2 diabetes is associated with greater brain atrophy and cognitive decline, and whether the two are linked.

It is the first piece of research to compare decline in both cognition and brain atrophy between people with and without type 2 diabetes together in the same study.

The trial recruited 705 people aged 55 to 90 years old from the Cognition and Diabetes in Older Tasmanians (CDOT) study. There were 348 people with type 2 diabetes with a mean age 68, and 357 without the condition with a mean age 72.

They underwent brain MRI and neuropsychological measures at three time points over a mean follow-up period of 4.6 years and the results were adjusted for age, sex, education and vascular risk factors including past or current smoking, heart attack, stroke, high blood pressure, high cholesterol, and body mass index.

The authors reported there were significant associations found between type 2 diabetes and greater decline in both verbal memory and verbal fluency.

Although people with diabetes had evidence of greater brain atrophy at the start of the study, there was no difference in the rate of brain atrophy between those with and without diabetes over the time course in this study.

There was also no evidence in the study that the rate of brain atrophy directly impacted on the diabetes-cognition relationship. In people without type 2 diabetes, verbal fluency slightly increased on average each year whereas it declined in those with type 2 diabetes.

‘Such accelerated cognitive decline may contribute to executive difficulties in everyday activities and health behaviours, such as medication compliance, which in turn may poorly influence future vascular health and cognitive decline, and possibly an earlier onset of dementia in those with type 2 diabetes,’ the study report says.

‘Contrary to our hypotheses and results from previous cross sectional studies, the rate of brain atrophy over these five years of study did not directly mediate associations between type 2 diabetes and cognitive decline. It is possible that greater accrual of cerebrovascular disease than occurred in our study may be more likely to reveal whether there is such a relationship,’ it points out.

‘In older people, type 2 diabetes is associated with a decline in verbal memory and fluency over approximately five years, but the effect of diabetes on brain atrophy may begin earlier, for example in midlife, given the evidence of greater brain atrophy in people with type 2 diabetes at the start of the study,’ it adds.

‘If this is the case, both pharmacological and lifestyle interventions to prevent brain atrophy in people with type 2 diabetes may need to commence before older age,’ it concludes.


The opinions expressed in this article do not necessarily reflect the views of the DiabetesForum.com Community and should not be interpreted as medical advice. Please see your doctor before making any changes to your diabetes management plan.

{ 0 comments… add one now }

Leave a Comment

Previous post:

Next post: