It is well-known that insulin resistance is common in people who are obese, pre-diabetic or have Type 2 diabetes. The fact that obesity increases the risk of cardiovascular disease and some cancers is known as well. Now, researchers from Iowa State University and the Wisconsin Alzheimer’s Institute have found found a strong association between insulin resistance and memory function decline, increasing the risk for Alzheimer’s disease using neuroimaging. The study is published in the Journal of the American Medical Association Neurology.
The current study examined brain scans in 150 late middle-aged adults, who were at risk for Alzheimer’s disease and showed no sign of memory loss. The neuroimaging focused on the medial temporal lobe, specifically the hippocampus, a critical region of the brain for learning new things and sending information to long-term memory. It is also one of the areas of the brain that first show massive atrophy or shrinkage due to Alzheimer’s disease.
The scans detected if people with higher levels of insulin resistance used less blood sugar in areas of the brain most susceptible to Alzheimer’s. The data findings show that when that happens the brain has less energy to relay information and function. The team explain that this is important with Alzheimer’s disease, because over the course of the disease there is a progressive decrease in the amount of blood sugar used in certain brain regions.
To the team’s knowledge this is the first study to look at insulin resistance in late middle-aged people, identify a pattern of decreased blood sugar use related to Alzheimer’s and link that to memory decline. Participants were recruited through the University of Wisconsin-Madison and Wisconsin Registry for Alzheimer’s Prevention study, an ongoing study that examines genetic, biological and lifestyle factors that contribute to dementia. The average age of study participants was 60.
The researchers state that the link between insulin resistance and Alzheimer’s disease is important for prevention, however, the risk is much more immediate. They go on to add that problems regulating blood sugar may impact cognitive function at any age. The lab conclude that testing for insulin resistance in obese patients and taking corrective action, through improved nutrition and moderate exercise, is a crucial first step.
The team surmise that patients can sometimes find it difficult to adjust their behaviour based on what might happen in the future. They go on to add that this is why people need to know that insulin resistance or related problems with metabolism can have an effect in the here and now on how they think, and it’s important to treat. The lab stress that for Alzheimer’s, it’s not just people with Type 2 diabetes. They note that even people with mild or moderate insulin resistance who don’t have Type 2 diabetes might have an increased risk for Alzheimer’s disease because they’re showing many of the same sorts of brain and memory relationships.
For the future the lab state that understanding the progression of cognitive decline will take additional research. They conclude that following those who are at-risk through the different stages of dementia and Alzheimer’s will offer insight as to what happens as their cognitive function declines.
Source: Iowa State University