"The number of people with Alzheimer's and the number that will soon get it is rising dramatically," said Ronald Peterson, professor of neurology at the Mayo Medical School in Rochester, Minn.
"A connection between Alzheimer's and diabetes has major public health implications," Peterson said, speaking at the 10th International Conference on Alzheimer's disease and Related Disorders this week in Madrid.
At the opening sessions of the meeting, researchers suggested that failure of diabetic patients to maintain control of their blood-sugar levels increased their risk of developing dementia 10 years down the road by as much as 78 percent when compared to those patients who were able to keep their disease under control.
Glycosated hemoglobin -- known as HbA1c -- kept under 10 percent in the blood appeared to be the point where the likelihood of developing dementia begins, said Rachel Whitmer, a researcher at Kaiser Permanente of Oakland, Calif.
In her study that involved 22,852 patients with adult-onset diabetes, HbA1c levels that were between 10 percent and 12 percent increased the risk of dementia by 16 percent over someone who kept blood sugars in control. The risk of dementia rose to 25 percent if that level was 12 percent to 15 percent and jumped dramatically to 78 percent if the level was over 15 percent.
"The least well controlled diabetics have the greatest increase in risk of dementia," Peterson told United Press International at a news briefing he chaired Sunday.
In another study, Laura Fratiglioni, director of the Aging Research Center at the Karolinska Institutet in Stockholm, Sweden, described how patients with borderline diabetes were 67 percent more likely to develop dementia nine years after diagnosis and were 77 percent more likely to develop Alzheimer's disease after nine years than people who had not shown difficulty in processing body sugars.
What's more, Fratiglioni told UPI that if a person with borderline diabetes also developed severe high blood pressure the risk of Alzheimer's disease soars to six times normal.
"We have been aware that diabetes is linked to dementia because it affects blood vessels, including blood vessels in the brain," said Donald Miller, associate professor of health services at the Boston University School of Public Health, "but now we are seeing specific links between diabetes and Alzheimer's disease."
Miller detailed his research that considered whether drugs known as thiazolidinediones -- such as Actos and Avandia -- might slow down the progression to Alzheimer's disease. He said the risk of Alzheimer's disease was 19 percent less if the patients were taking the newer anti-diabetes medicines than if they were not on those drugs. The study looked at records of 142,328 veterans treated in Veterans Affairs hospitals.
While those results are intriguing, Miller said further studies will need to be performed to see if the diabetes drugs can be used to protect people against dementias.
Another researcher, David Geldmacher, director of the memory-disorders program at the University of Virginia in Charlottesville, performed a small study of 25 patients with Alzheimer's disease who were given Actos in attempts to slow the progression of the disease. The results appeared to show some areas of improvement, which Geldmacher said were promising enough to move forward to further testing.
While the drug studies may be promising, Geldmacher urged patients to exercise more and reduce their lifestyle risk for diabetes while research continues.