Hippocampal atrophy advances with the years that diabetes is present, according to the researchers.
The study’s subjects were residents of Hisayama, Fukuoka Prefecture, southern Japan, where the university is conducting a long-term epidemiological survey.
Earlier sessions of the survey found that people with diabetes have double the risk of developing dementia compared to people without the disease.
The latest study provided the evidence that the brains of people with diabetes are actually damaged by the disease.
“The changes in the brains may have started in diabetics even if they haven’t developed dementia yet,” the research team said.
The findings were presented at a scientific session of the American Diabetes Association, which were held through June 14 in New Orleans, La.
During the study, researchers measured the brain volumes of Hisayama residents aged 65 years or older using magnetic resonance imaging (MRI) of the head and examined the differences between the brains with the presence or absence of diabetes. Of 1,238 participants, 286 had diabetes.
As brain size varies from person to person, researchers assessed the extent of brain atrophy under the guideline “the ratio of brain volume to the volume of the inner skull.” The researchers also used statistical procedures to prevent the participants’ ages from affecting the results.
The results then showed the tendency that the longer patients have the disease, the more likely it is that their brains get smaller.
In particular, the volume of the memory-related hippocampus, located deep within the brain, was about 3 percent smaller among participants who had lived with diabetes for 10 to 16 years than those without the disease. For those with more than 17 years of living with diabetes, it was about 6 percent smaller than in non-diabetics, the results found.
Although diabetes can damage blood vessels and make them fragile, therefore raising the risk of neurological disorders and kidney damage, the disease can apparently damage brains as well.
Types of diabetes that tend to sharply increase blood sugar levels after eating are especially related to the risk of brain atrophy, the researchers said.
“Diabetes also heightens the risks of strokes and other diseases,” said research team member Jun Hata, an associate professor of epidemiology at Kyushu University.
“First and foremost, we should be careful not to become diabetic.”
On the other hand, it is believed that exercise lowers the risk of developing diabetes and dementia.