Alzheimer’s is by far the most common form of dementia, and it has long been known that diabetes makes it more likely. The new study tracked blood sugar over time in people with and without diabetes to see how it affects risk for the mind-robbing disease.
The results challenge current thinking by showing that it’s not just the high glucose levels of diabetes that are a concern, said the study’s leader, Dr. Paul Crane of the University of Washington in Seattle.
“This is part of a larger picture” and adds evidence that exercising and controlling blood pressure, blood sugar and cholesterol are a viable way to delay or prevent dementia, said Dallas Anderson, a scientist at the National Institute on Aging, which paid for the study.
In the United States, about 5 million have Alzheimer’s disease. People who have diabetes don’t make enough insulin, or their bodies don’t use insulin efficiently enough, to turn food into energy. That causes sugar in the blood to rise, which can damage the kidneys and other organs – possibly the brain, researchers say.
The new study, published in Thursday’s New England Journal of Medicine, involved 2,067 people 65 and older in the Group Health Cooperative, a Seattle-area health care system. At the start, 232 participants had diabetes; the rest did not.
They each had at least five blood-sugar tests within a few years of starting the study and more after it was under way.