Type 2 Diabetes May Have Link to Alzheimer’s


Study Shows Insulin Resistance May Raise Risk of Brain Plaques Associated With Alzheimer’s

Aug. 25, 2010 — People with insulin resistance or type 2 diabetes may be at increased risk for developing telltale brain plaques that are closely linked to Alzheimer’s disease, a study shows.

The new findings, which appear in the Aug. 25 issue of Neurology, may give more evidence of the connection between diabetes and Alzheimer’s disease.

In insulin resistance, the hormone insulin, produced by the pancreas, becomes less effective in lowering blood sugar.  People with insulin resistance are at risk for developing type 2 diabetes.

“Type 2 diabetes and Alzheimer’s disease are two epidemics growing at alarming levels around the world,” says study researcher Kensuke Sasaki, MD, PhD, with Kyushu University in Fukuoka, Japan, in a news release. “With the rising obesity rates and the fact that obesity is related to the rise in type 2 diabetes, these results are very concerning.”

Checking for Signs of Alzheimer’s

In the new study, 135 Japanese men and women underwent diabetes screening tests in 1988 and were followed for up to 15 years for signs of Alzheimer’s disease. Overall, 16% showed signs of clinical Alzheimer’s disease before they died; 65% of people in the study also showed evidence of plaques in their autopsied brains after death.

People who had abnormal results on their blood sugar tests were more likely to have plaques in their brain, the study shows. This relationship was more pronounced among people who also had a form of the ApoE gene that’s been linked to a higher risk of developing Alzheimer’s disease.

There was no link between insulin resistance and type 2 diabetes and risk for developing brain tangles, another brain abnormality seen with Alzheimer’s disease, the study shows.

“Further studies are needed to determine if insulin resistance is a cause of the development of these plaques,” Sasaki says. If it is,”it’s possible that by controlling or preventing diabetes, we might also be helping to prevent Alzheimer’s disease.”

The new study “supports the hypothesis that insulin resistance and type 2 diabetes is causally related to a higher risk of dementia including Alzheimer’s disease,” writes Jose A. Luchsinger, MD, MPH, in an accompanying editorial.

More studies are needed to figure out precisely how the conditions are connected, he writes.

“This is urgent considering that over half of the U.S. population in the age group most at risk for cognitive impairment has prediabetes or type 2 diabetes,” he writes.

Some current trials are looking at how available insulin-sensitizing drugs affect cognitive impairment.

Prophylactic Use of an Intra-Aortic Balloon Pump


Findings from a randomized study show no benefit in patients at high risk for complications of percutaneous coronary intervention.

Intra-aortic balloon pumps (IABPs) are commonly used to reduce the likelihood of complications in stable high-risk patients undergoing percutaneous coronary intervention (PCI). Investigators for the randomized controlled Balloon Pump–Assisted Coronary Intervention Study evaluated this practice in 301 patients (mean age, 71; 80% men) with left ventricular (LV) ejection fractions of ≤30% and a large amount of myocardium at risk. The investigators excluded patients who fulfill American College of Cardiology/American Heart Association Class I and II recommendations for IABP use: cardiogenic shock, acute myocardial infarction (AMI) within 48 hours before scheduled PCI, or complications of AMI requiring circulatory support. The primary endpoint was the composite of death, AMI, stroke, or further revascularization before hospital discharge.

Twelve percent of patients assigned to no planned IABP underwent rescue IABP insertion. A primary endpoint occurred in 15% of the IABP group and in 16% of the no-planned–IABP group. Three deaths occurred in the IABP group compared with one death in the no-planned–IABP group. MI occurred in about 13% of each group. Two strokes occurred in the IABP group and none in the no-planned–IABP group. Predefined procedural complications (primarily hypotension) were less frequent in the IABP group than in the no-planned–IABP group (1% vs. 11%). However, bleeding was more common in the IABP group (19% vs. 11%), as were access-site complications (3% vs. 0%).

Comment: This trial failed to demonstrate a benefit of elective IABP use in stable high-risk patients undergoing PCI. The results are not definitive; importantly, patients with a Class I or II indication for the device were excluded, and the guideline recommendation for hemodynamic support in these highest-risk patients remains unchallenged. Nonetheless, these findings not only call into question the merits of routine IABP placement in patients with severe LV dysfunction and extensive coronary disease, they also illustrate the importance of testing such “common-sense” strategies in clinical trials.

Published in Journal Watch Cardiology August 25, 2010