Past studies have linked diabetes to increased risk of cognitive decline. Now, new research suggests that people who develop diabetes and high blood pressure in middle age may be at higher risk of brain cell loss and memory and thinking problems, compared with those who do not have either condition or develop them later in life.
The research team, including Rosebud O. Roberts of the Mayo Clinic in Rochester, MN, recently published their findings in the journal Neurology.
For the study, the researchers assessed the thinking and memory skills of 1,437 individuals with an average age of 80. The participants had either mild cognitive impairment or no memory and/or thinking problems.
The researchers also analyzed the subjects' medical records to determine their history of diabetes and blood pressure, and whether they had been diagnosed with either condition during middle age or later. Middle age was defined as between 40 and 64 years old.
Participants then underwent brain scans so the investigators could search for markers of brain damage that may be a precursor to dementia.
Effects of diabetes and high blood pressure on brain 'take decades to impact brain'
The researchers found that 72 people developed diabetes in middle age, while 142 developed the condition in old age and 1,192 did not have diabetes at all. For high blood pressure, 449 participants developed the condition in middle age, 448 developed it in old age and 369 did not have it.
The brain scans revealed that people who developed diabetes in middle age had a 2.9% smaller total brain volume and a 4% smaller volume in the hippocampus - the area of the brain primarily associated with memory - compared with those who did not have diabetes.
The team also found that individuals who developed diabetes in middle age were twice as likely to have memory and thinking problems than those without diabetes.
People who developed high blood pressure in middle age were twice as likely to have areas of brain damage than those who did not have high blood pressure.
The team also found that people who developed diabetes in old age were also more likely to have areas of brain damage, but developing high blood pressure in old age did not seem to have any adverse effects on the brain.
Commenting on the findings, Roberts says:
"Overall, our findings suggest that the effects of these diseases on the brain take decades to develop and show up as brain damage and lead to symptoms that affect their memory and other thinking skills.
In particular, diabetes has adverse effects regardless of the age at which diabetes develops."
Roberts says that if diabetes and high blood pressure can be prevented in middle age, this would potentially prevent brain damage and cognitive problems later in life.
Medical News today recently reported on a study suggesting that eating grilled meat may increase the risk of both Alzheimer's and diabetes.