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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

WSU partners in study finding Type 1 diabetes glucose fluctuations hamper brain function

Type 1 diabetes patients showed slower and less accurate cognitive responses when their blood sugar levels were too low or high, according to a study that gives another reason for diabetics to avoid extremes in their daily lives.

The study measured how large swings in blood glucose levels might affect the type of quick thinking that’s important for everyday tasks, from driving and operating machinery to fast decisions in a quick-paced environment. Researchers at Washington State University and McLean Hospital joined in reviewing the impacts.

“It’s similar to being sleep deprived, when maybe you feel like you’re not thinking as quickly, or as well,” said co-senior author Naomi Chaytor, a Spokane professor and chair in the WSU Elson S. Floyd College of Medicine.

“One of the main findings from the paper is that minimizing those glucose extremes is going to maximize your cognition. Obviously, we want to minimize extremes for other reasons, but this is an additional reason.”

The most dramatic effect on cognitive thinking was seen at low glucose levels. More research and a better understanding of these impacts might play a role in preventing long-term cognitive issues such as dementias for Type 1 patients, and indicates people should avoid glucose extremes even in middle age, Chaytor added.

Such findings aren’t a surprise to Brea Seaburg, a Spokane nurse practitioner diagnosed with Type 1 diabetes more than four years ago.

“When my blood sugar is low, it just feels like it takes longer to get those words out; it takes longer to form my thoughts,” Seaburg said.

“It’s very worthwhile research. Keeping those numbers within a tighter, more normal range with less variability, from a purely patient standpoint, you just feel better. From a medical perspective, I think there are biomarkers suggesting lower levels of inflammation and stress on the body when there’s not quite as much variability.”

Josh Neumiller, who wasn’t involved in this study, is a professor in the WSU College of Pharmacy and Pharmaceutical Sciences. He’s had Type 1 nearly 20 years. Neumiller also does separate diabetes research and is a diabetes educator.

“In terms of the highs and lows of blood sugar, that definitely rings true,” he said. “You feel like you’re in a fog, if you’re going from high and low during the day. When people with Type 1 have these large swings in blood sugar, it just makes you feel fatigued both physically and mentally.”

Type 1 diabetes, previously called juvenile diabetes, is an autoimmune disorder in which the body’s immune system destroys insulin-producing cells in the pancreas, so the body produces little or none of the hormone that enables blood sugar to enter the body’s cells for energy.

Type 2 diabetes is an impairment in the way the body regulates and uses blood sugar, or glucose, as a fuel. In 2021, 38.4 million Americans had diabetes. The CDC estimates about 5-10% of those have Type 1, while 90-95% have Type 2.

Researchers previously were limited in studying Type 1 glucose fluctuations related to short-term cognitive function, but that changed in recent years with technology both for cognitive testing and to monitor glucose levels, Chaytor added.

For decades, cognitive testing only was done in a clinic with pencil and paper, but that changed after COVID-19 and advances in smartphones.

The study had 200 people, ages 18 to 84, all who used a provided continuous glucose monitoring device that automatically reads blood glucose level, or blood sugar, every few minutes, day and night.

Through a 15-day study, people did the cognitive tests three times a day. Meanwhile, the research team captured the repeated data on glucose measurements taken every 5 minutes.

“We know that long term, people with Type 1 diabetes are at higher risk for cognitive decline, dementia and brain-based changes due to the diabetes,” Chaytor said. “But we also know some people are at higher risk for that than others. We wanted to see, could this kind of vulnerability to glucose in the short term be a signal that someone’s brain is not optimal, that they’re more vulnerable?

“Are the things associated with long-term cognitive decline in Type 1, do those also associate with being more vulnerable through acute changes in glucose in the short term? And that’s essentially what we found.”

It’s a key to understanding possible brain vulnerability before noticeable cognitive decline, she said.

Chaytor and Zoë Hawks, a McLean researcher, want to understand this with more research, because “we don’t want to wait until they’re older,” Chaytor added. “We want to address these things midlife.”

One study surprise was that participants’ peak cognitive performance coincided with glucose levels that were slightly above their normal range, although performance dropped off as levels rose even further. But it’s possible that the brain habituates itself to that certain glucose level, Chaytor said,

Overall, it’s relatively new to study brain cognition in Type 1 diabetes, she said.

“In recent years, there’s been a better understanding of how glucose metabolism and insulin metabolism impacts brain function,” she said. “The focus has been on dementia risk, primarily in Type 2 diabetes, that there’s an increased risk for Alzheimer’s and vascular dementia, so we started looking at that in Type 1 diabetes, as well.”

The WSU-McLean research also showed that older people, and those with certain health conditions such as kidney damage, might be more affected by glucose extremes. The study was novel in that it was the first to compare moment-to-moment glucose variations with moment-to-moment changes in cognition.

Depending on medication and technology, it’s getting somewhat easier for patients to maintain a glucose range, Neumiller said. That includes newer insulins and technology that loops glucose monitoring devices with automated insulin pumps to minimize fluctuations.

Although he uses such a system and it works most days, “they’re not foolproof, and I still run into issues where I have lows and highs.”

Fluctuations can vary by individuals and other factors. Highs and lows can impact daily activities, he said.

“All kinds of things can affect our blood sugars, from what we eat to the amount of physical activity we’re engaging in, and differences in how our insulin works from day to day,” he said.

“We do really encourage people to check their blood sugar before they get behind the wheel of a car to make sure they are safe,” Neumiller said. “Another issue with this is you can be confused when your blood sugar is low and not really recognize that you’re impaired.”