They also had lower scores on several tests of memory and thinking skills – and found it harder to carry out daily tasks such as bathing and cooking.
In previous studies, Novak and her colleagues showed that people with diabetes have brains that look five years older than those of similar-aged controls; for children with the disease, that could take a drastic toll on their cognitive skills as they age.
The study was published online July 8 in the journal Neurology. About half had type 2 diabetes, and half did not. It was funded by the USA National Institute on Aging, the American Diabetes Association, the Harvard Clinical and Translational Science Center and the USA National Center for Research Resources.
The bodies of patients with type 2 diabetes fail to use insulin efficiently and can’t make enough of it to keep blood sugar levels under control.
A study by experts at Harvard Medical School suggests that the impact can be seen in memory and cognition tests – with the decrease in thinking skills dropping over just two years.
Many factors contribute to cognitive decline in those with diabetes, the study authors said. The volunteers completed thinking and memory tests. Those with diabetes had been treated for the disease for an average of 13 years. On a test of learning and memory, the scores of the people with diabetes decreased by 12 per cent, from 46 points to 41 points over the span of two years, on the other hand, for those without diabetes, the scores stayed the same at 55 points. What this means is that type 2 diabetes patients who remembered 10 words on the first round of tests, only remembered 8 or 9 in the second one. “It’s only [in] two years, that’s what is concerning”. Both at the study’s start and more noticeably after two years, blood vessels in the diabetics’ brains showed less ability to expand and contract to accommodate changing mental tasks.
“Higher levels of inflammation were also associated with greater decreases in blood flow regulation, even if people had good control of their diabetes and blood pressure”, Novak said.
Dr. Marc Gordon, chief of neurology at Zucker Hillside Hospital, North Shore Long Island Jewish Health System, Manhasset, said it’s not new to suggest type 2 diabetes is linked with inflammation and stress to the cells that can lead to problems in the blood vessels.
“Early detection and monitoring of blood flow regulation may be an important predictor of accelerated changes in cognitive and decision-making skills”, Novak said.
The research could explain why people with diabetes are at an increased risk of dementia.
What drove the decline, says Novak, were changes in the brains of the diabetic patients.
The researchers added that a study with a larger group of people and done for a longer time is needed to better understand how type 2 diabetes may affect blood flow to the brain.