Study author Dr. Vera Novak, from Harvard Medical School, explains, "People with type 2 diabetes have impaired blood flow regulation. Our results suggest that diabetes and high blood sugar impose a chronic negative effect on cognitive and decision-making skills. Early detection and monitoring of blood flow regulation may be an important predictor of accelerated changes in cognitive and decision-making skills."
Wanting to investigate how inflammation, blood flow regulation in the brain and cognitive decline were related in people with the metabolic disorder, the researchers examined 40 people -- 19 with type 2 diabetes and 21 without it. The average age of the participants was 66. Participants who had type 2 diabetes had been treated for the disease for more than 5 years, receiving an average of 13 years of treatment. The researchers assessed participants' cognitive and memory functions while also measuring brain volume, blood flow and inflammation.
After 2 years, the researchers repeated the tests and discovered that the participants with type 2 diabetes experienced a reduction in their capacity to regulate the blood flow in their brains and performed worse in the cognitive and memory function tests. Average test scores fell by 12 percent, from 46 to 41, among those with type 2 diabetes, while the scores of those without diabetes remained steady at 55 points. Among the participants with type 2 diabetes, blood flow regulation fell by around 65 percent overall.
Other researchers have made the case for a link between type 2 diabetes and Alzheimer's disease, even going so far as calling Alzheimer's disease "type 3 diabetes." According to the Mayo Clinic, diabetes and Alzheimer's disease are connected in ways not completely understood. Studies indicate that people with diabetes, especially type 2 diabetes, are at higher risk of eventually developing Alzheimer's disease or other dementias and should take steps to prevent or control diabetes (http://www.mayoclinic.org/diseases-conditions/alzheimers-disease/in-depth/diabetes-and-alzheimers/art-20046987).
Diabetes can cause several complications, such as damaging blood vessels, says the Mayo Clinic. Diabetes is considered a risk factor for vascular dementia, which occurs because of brain damage triggered reduced or blocked blood flow to the brain. It is also possible that Alzheimer's disease can be the result of the complex ways that type 2 diabetes affects the ability of the brain and other body tissues to use sugar (glucose) and respond to insulin.