Youth-onset diabetes linked to higher Alzheimer's risk

By Katie Robinson | Fact-checked by Barbara Bekiesz
Published June 17, 2024

Key Takeaways

  • Young people with diabetes may be at greater risk of developing Alzheimer’s disease (AD) later in life than their peers without diabetes, according to a recent study.

  • Investigators found markers of AD in the blood of teens and young adults with type 1 and type 2 diabetes.

  • The study results show that physicians may want to recommend cognitive testing for their young patients with diabetes.

Young people with diabetes may be at greater risk of developing AD later in life than their peers without diabetes, according to investigators at the University of Colorado Anschutz Medical Campus. Their new study, published in the journal Endocrines, found biomarkers in the blood of teens and young adults with type 1 and type 2 diabetes, indicating early signs of neurodegeneration and AD.[]

“Preliminary evidence shows that preclinical AD neuropathology is present in young people with youth-onset diabetes,” said lead author Allison Shapiro, PhD, in a university press release.[]

"These preliminary data suggest the potential for an early-onset AD risk trajectory in people diagnosed with diabetes in childhood or adolescence."

Allison Shapiro, PhD

Diabetes prevalence

According to 2021 data from the American Diabetes Association, 38.4 million people in the US have diabetes, representing 11.6% of the population.[] This includes about 352,000 individuals younger than age 20, representing around 0.35% of this younger population. The estimated incidence (in 2017–2018) of youth diagnosed with diabetes each year is 18,200 for type 1 diabetes and 5,300 for type 2 diabetes.

In adults, the average age of diabetes onset is 46 years, by which time people with youth-onset diabetes have lived with their disease for more than 30 years. 

While individuals with adult-onset diabetes have as much as an 80% increased risk for cognitive impairment and AD, little research has investigated the link between youth-onset diabetes and AD risk.

Proof-of-concept study

The study by the Colorado researchers included 25 people with type 1 diabetes and 25 with type 2 diabetes. Their ages ranged from 15–27 and 59% were female. The investigators compared the participants to a group without diabetes, which included 25 teens (age approximately 15) and 21 young adults (age approximately 25).

Specifically, the study analyzed the participants’ blood for the presence of biomarkers associated with AD and cognitive impairment. The biomarkers included glial fibrillary acidic protein (GFAP) for nerve degeneration and neurofilament light chain protein (NfL) for inflammation of the nervous system, along with phosphorylated tau-181 (pTau181) and amyloid beta (Aβ40, Aβ42) for pathology of the nervous system linked to AD. Additionally, seven of the young adults with diabetes and six without diabetes underwent positron emission tomography (PET) brain scans to measure the density of amyloid and tau in AD-sensitive areas of the brain.

The results showed that the teens and young adults with diabetes had lower GFAP levels and higher pTau181 levels compared with the participants without diabetes. Those with diabetes also presented with lower plasma levels of Aβ40 and Aβ42, suggesting early and sustained amyloid irregularity in youth-onset diabetes.

All AD biomarkers increased from adolescence to adulthood in participants with diabetes. For the young adults who underwent brain scans, no significant differences in amyloid or tau were seen in those with and without diabetes.

The obesity link

AD is often seen as a late-life disease, but the results from this study suggest that early-life factors may contribute to the development of AD, Dr. Shapiro said.[] She highlighted that around 20% of young people in the US have obesity, which contributes to diabetes and inflammation—conditions linked to AD and an array of other diseases.

“We are about to enter into a different world of healthcare because of the obesity epidemic in young people. Young people are catching up with adults. We are now seeing more aging-related diseases in young people,” Dr. Shapiro said.[]

Clinicians are recognizing the importance of cognitive testing in adults with diabetes as a part of follow-up, explained Dr. Shapiro, who suggested that such testing be considered in individuals with youth-onset diabetes as well.

What this means for you

Teens and young adults with type 1 and type 2 diabetes may be at increased risk of developing AD in later life than their peers without diabetes. Cognitive testing as part of follow-up should be considered in young patients with diabetes. Obesity is on the rise in young adults, which may be exacerbating the issue.

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