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Scientists ID Diabetes Link to Cognitive Impairment in Older Adults
Many complications of diabetes, including kidney disease, foot problems, and vision problems are generally well recognized. But the disease's impact on the brain is often overlooked. For the past five years, a team led by Beth Israel Deaconess Medical Center (BIDMC) neurophysiologist Dr. Vera Novak, has been studying the effects of diabetes on cognitive health in older individuals and has determined that memory loss, depression, and other types of cognitive impairment are a serious consequence of this widespread disease. Now, Dr. Novak's team has identified a key mechanism behind this course of events. In a study published in the November 2011 issue of the journal Diabetes Care, they report that in older patients with diabetes, two adhesion molecules – sVCAM and sICAM – cause inflammation in the brain, triggering a series of events that affect blood vessels and, eventually, cause brain tissue to atrophy. Importantly, they found that the gray matter in the brain's frontal and temporal regions -- responsible for such critical functions as decision-making, language, verbal memory, and complex tasks – is the area most affected by these events. "In our previous work, we had found that patients with diabetes had significantly more brain atrophy than did a control group," explains Dr. Novak, Director of the Syncope and Falls in the Elderly (SAFE) Program in the Division of Gerontology at BIDMC and Associate Professor of Medicine at Harvard Medical School. "In fact, at the age of 65, the average person's brain shrinks about one percent a year, but in a diabetic patient, brain volume can be lowered by as much as 15 percent." Diabetes develops when glucose builds up in the blood instead of entering the body's cells to be used as energy. Known as hyperglycemia, this condition often goes hand-in-hand with inflammation. Dr.