By Serena Gordon
FRIDAY, Dec. 14, 2018 (HealthDay News) -- Diabetes has been tied to a number of complications such as kidney disease, but new research has found that older people with type 2 diabetes can also have more difficulties with thinking and memory.
During a five-year study, participants with diabetes showed a decline in verbal memory and fluency. Using MRI scans, researchers saw that the participants' brains were smaller at the start of the study -- but the rates of decline in brain size did not differ over the years the patients were followed. The investigators didn't find a connection between brain size and the thinking and memory troubles.
"Although memory and executive function [thinking and planning skills] declined at a greater rate in people with type 2 diabetes, this was not explained by a decline in brain volume," said study author Michele Callisaya, a research fellow at the University of Tasmania.
Callisaya said the researchers were surprised by this finding. They expected that decreased brain volume would have been more common in people who were having memory and thinking issues. But she added that it's possible over a longer time, a relationship between these factors might become evident.
And, she added, "The overall message is that type 2 diabetes affects brain function."
Past research has found that having diabetes might double a person's risk of dementia, the researchers said. Although previous studies have shown the connection between the two conditions, none has proven a cause-and-effect relationship. That's what prompted Callisaya and her colleagues to look at whether or not a loss of brain volume might be behind the connection.
They recruited more than 700 people between 55 and 90 years old for the study. At three different points during the five years, the participants underwent testing to measure their thinking, planning and memory skills. They also had an MRI scan each time.
About half of the participants had type 2 diabetes (348 people) and their average age was 68. The group without diabetes had an average age of 73.
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