Diabetes, one of the most common chronic diseases in the U.S., deteriorates almost every part of the body, and researchers are still discovering just how far this damage extends. In a new study, researchers have found that the length of time a person has diabetes, as well as its severity, can affect the level of deterioration the brain goes through, eventually leading to cognitive decline.

“We found that patients having more severe diabetes had less brain tissue, suggesting brain atrophy,” said lead author Dr. R. Nick Bryan, a professor of radiology at the Perelman School of Medicine at the University of Pennsylvania. The researchers concluded that patients’ brain atrophy was linked more to diabetes than a commonly believed cause, small vessel ischemic disease, which damages the blood vessels leading to the brain, eventually depleting oxygen and causing cognitive decline.

For their study, Bryan and his colleagues used magnetic resonance imaging (MRI) to measure the size of 614 patients’ brains — every patient had type 2 diabetes mellitus. They compared the size of each patient’s brain to the severity and length of time that they had the disease — the average time was about 10 years — as well as whether a more atrophied brain also had more ischemic lesions.

They found that although participants’ brains were more likely to show deterioration with longer-lived diabetes, they weren’t more likely to show the lesions. Specifically, the brains deteriorated most in areas with gray matter, or the part of the brain responsible for routing and processing stimuli. “Diabetes duration correlated primarily with brain atrophy,” Bryan said in the release. “Stated another way, our results suggested that, for every 10 years of diabetes duration, the brain of a patient with diabetes looks approximately two years older than that of a non-diabetic person, in terms of gray matter volume.”

Diabetes affects an estimated 25.8 million children and adults, or about eight percent of the population. Of those, about 90 to 95 percent have type 2 diabetes, which develops as a result of insulin deficiency or the body’s inability to use it correctly. The new research gives doctors and other research scientists a new basis for developing management techniques for diabetes, as well as a new understanding of the chronic disease’s true effect on patients, the researchers said.

Source: Bryan N, Bilello M, Launer L, et al. Effect of Diabetes on Brain Structure: The Action to Control Cardiovascular Risk in Diabetes MR Imaging Baseline Data. Radiology. 2014.