Undiagnosed prediabetes and diabetes are common in people with early Alzheimer's disease, a researcher says.
Georgetown University neurologist Dr R. Scott Turner made the finding when he began enrolling people with mild to moderate Alzheimer's disease into a study last year. The study's goal was to determine if resveratrol, a compound found in red grapes and red wine, might change blood sugar (glucose) levels in patients with mild to moderate Alzheimer's disease.
Turner said he was shocked by what he found in this group of patients because they were already under a doctor's care, and those with known diabetes were excluded from the study.
"The number of people with glucose intolerance (prediabetes) was much higher than expected," Turner said in a university medical centre news release. "I was surprised by how many people didn't know they were prediabetic, and these are individuals who already get the best medical care."
Impaired glucose tolerance
To join the study, patients were first given a fasting glucose tolerance test, and then retested two hours after eating. The blood sugar level increases during digestion, but the pancreas produces insulin to lower it. A high sugar level after two hours reveals glucose intolerance (prediabetes) or diabetes if the level is very high.
Five of 128 patients (4%) had impaired fasting glucose levels. Meanwhile, 2% had findings consistent with type 2 diabetes. Of the 125 patients who completed the two-hour test, 30% had glucose intolerance while 13% had results consistent with diabetes. The findings showed that 43% of the patients had impaired glucose tolerance or diabetes at two hours.
Turner said the results raise a number of questions: "How does glucose intolerance or diabetes lead to [Alzheimer's disease]? Does the inflammation associated with Alzheimer's trigger glucose intolerance? Or do both events create a vicious cycle of Alzheimer's and glucose intolerance?"
Although the study wasn't designed to answer these questions, it may offer important clues. "Although a glucose tolerance test is not typically ordered by neurologists, this result suggests that perhaps we should test all our patients with early Alzheimer's," Turner said. "It's a simple, inexpensive study that reveals critical health information."
Turner was scheduled to present his findings on Sunday at the Alzheimer's Association International Congress in Boston. The data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
The U.S. Centers for Disease Control and Prevention has more about prediabetes.