Biomarkers of Alzheimer's disease identified in young people with diabetes

With obesity rates rising in the United States and around the world, the prevalence of diabetes is also expected to increase, affecting more young people.

Previous studies have shown that people over 40 with these biomarkers are 60% to 80% more likely to develop dementia or Alzheimer's disease.

New research shows that biomarkers associated with the development of Alzheimer's disease (AD) later in life are present in people with type 1 and type 2 diabetes that began in at a young age.

The study authors observed blood biomarkers associated with Alzheimer's disease, as well as increased levels of amyloid protein in brain regions associated with Alzheimer's disease in adolescents and young adults with diabetes.

This study is the first to examine the presence of these potential preclinical signs of Alzheimer's disease in adolescents and young adults. The study was recently published in the journal Endocrines.

“There is a growing body of research examining how the pathophysiology of diabetes may contribute to the development of Alzheimer's disease and dementia,” said study first author Allison L. Shapiro, MD, MPH, assistant professor of pediatric endocrinology at the University of Colorado.

“Main hypotheses include insulin dysregulation (eg, insulin resistance and impaired insulin secretion) and hyperglycemia,” she said.

What is the connection between diabetes and Alzheimer's disease?

The present study's authors note that previous studies have shown that people with adult-onset diabetes are 60 to 80 percent more likely to develop dementia or Alzheimer's disease compared with those without diabetes.

For the new study, researchers at the University of Colorado Anschutz Medical Campus analyzed data from the SEARCH cohort.

In this cohort, 25 people had type 1 diabetes and 25 people had type 2 diabetes. The average age of the youngest group was 15 years, and the younger adults were about 27 years old. Of the entire group, 59% were women.

A healthy control group provided a basis for comparison. It included 25 teenagers, just under 15 years of age, and 21 young adults with an average age of about 25 years.

Blood plasma from the SEARCH cohort was analyzed for biomarkers of Alzheimer's disease. In addition, the new study recruited seven people with diabetes from the cohort and six controls for PET brain scans.

People with young-onset diabetes were noted to have higher levels of blood biomarkers associated with Alzheimer's disease.

The scans revealed the presence of densities of amyloid and tau—both associated with Alzheimer's disease—in areas of the brain associated with Alzheimer's among those who had the biomarkers. However, these differences did not reach statistical significance.

What type of diabetes is associated with Alzheimer's disease?

Shapiro said the study was too small to determine which type of diabetes carries the greatest risk.

“We will need larger groups of people and longer follow-up times to fully answer this question,” she said.

It is also not yet known whether a person with early onset diabetes will continue to exhibit biomarkers associated with Alzheimer's disease as they age.

“Other studies in adults who developed diabetes in adulthood have shown similar trends to what we found in our younger adults with young-onset diabetes,” Shapiro said.

“Together with the data in adults, we would hypothesize that the trends we see in young adulthood will continue into later life.”

Courtney Kloske, Ph.D., director of scientific affairs for the Alzheimer's Association, who was not involved in the study, noted that both Alzheimer's disease and diabetes are complex diseases.

“Research shows that they share some underlying mechanisms, such as disruptions in the energy production of certain cells,” Kloske said.

Kloske noted that diabetes and cardiovascular problems, such as hypertension and cholesterol problems, are risk factors for cognitive impairment and dementia, including Alzheimer's disease.

Kloske cautioned against taking the study as definitive, saying it has limitations that mean "we can't take their findings as definitive, but they certainly merit further research."

She said the study was too small and preliminary to “test the idea that early-onset diabetes may begin a series of changes in the brain that ultimately lead to cognitive decline and/or dementia.”

What can reduce the risk of Alzheimer's disease?

“Although research into diabetes and Alzheimer's disease is accelerating, there is still not enough information at this time to determine exactly what it is about diabetes that contributes to the increased risk of Alzheimer's disease and dementia,” Shapiro said.

“For people with diabetes, continuing to control their blood sugar levels is a good practice to prevent diabetes complications. This practice may also help prevent the increased risk of cognitive problems due to Alzheimer's disease and dementia." — Allison L. Shapiro, MD, MPH, first author of the study

The most immediate action that can be taken for those at high risk is regular cognitive assessments to monitor the progression of dementia or Alzheimer's disease.

“Risk factors for Alzheimer's disease and other dementias occur throughout life,” Kloske said.

“The sooner we can identify changes in the brain and intervene, and the longer we can practice brain-healthy habits, the better,” she added.

Kloske noted that the Alzheimer's Association provides guidelines for maintaining brain health, emphasizing the following health and lifestyle recommendations:

• regular physical activity
• diabetes and blood pressure management
• avoiding smoking
• good sleep
• balanced nutrition.

Kloske also mentioned a study called U.S. POINTER.

This two-year clinical trial, she explained, “is assessing whether lifestyle interventions targeting multiple risk factors simultaneously can protect cognitive function in older adults (aged 60-79 years) who are at increased risk of cognitive decline " Data and test results are expected in 2025.