People who develop type 2 diabetes or high blood pressure in middle age appear more likely to suffer brain damage that can contribute to dementia as they grow older, a new study finds.
Diabetes might actually shrink the brain over a long period of time, reducing the size of crucial areas like the hippocampus, which plays an important role in short- and long-term memory, according to the study.
Additionally, diabetes and high blood pressure both seem to increase a person’s risk of micro-strokes and other damage to the blood vessels that feed the brain, the study authors said.
“People who had diabetes earlier in life had much worse brain [structure] than those who had it later in life,” said lead author Dr. Rosebud Roberts, a Mayo Clinic researcher. “These scans are showing us that cognitive impairment happens over a long period of time. The earlier you develop type 2 diabetes, the more likely you are to have damage.”
Diabetes has long been linked to problems with thinking and memory later in life, but this study is the first to provide solid evidence explaining why that occurs, said Keith Fargo, director of scientific programs and outreach for the Alzheimer’s Association.
“We are very excited about this study,” Fargo said. “It has been known for quite some time that there is some kind of link between diabetes and cognitive ability later in life. What has not been known yet is why this link exists and how it develops over time.”
The study involved more than 1,400 people with an average age of 80, according to the report published online March 19 in the journal Neurology. The study participants had at most slight memory and thinking problems called mild cognitive impairment. The researchers assessed the participants’ thinking and memory skills, noting any signs of mild impairment.
The study participants then underwent MRI brain scans to look for signs of brain damage that can be an early indication of dementia.
Finally, the researchers reviewed the participants’ medical records to see whether they had been diagnosed with diabetes or high blood pressure in middle age, which, for the purposes of this study, ran from 40 to 64.
The study authors found that people who developed diabetes in middle age had brains that were on average 2.9 percent smaller than people who didn’t have diabetes. And their hippocampi were even smaller — an average of 4 percent smaller than those of non-diabetics.
“When your hippocampus begins to shrink, you begin to lose your long-term memory and your ability to remember recent events,” said Roberts, who also is a member of the American Academy of Neurology.
Source: web md