Type 2 diabetes linked to higher dementia risk, especially at younger ages

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A new study in the journal Diabetologia has found a link between Type 2 diabetes (T2D) and an increased risk of developing dementia later in life.

The risk appears to rise the younger a person is when they develop T2D.

The study was conducted by Jiaqi Hu, a Ph.D. student, Professor Elizabeth Selvin of the Johns Hopkins Bloomberg School of Public Health in Baltimore, and their colleagues.

The Role of Prediabetes

The researchers focused on the relationship between prediabetes and dementia.

Prediabetes is an intermediate stage of high blood sugar levels, not yet reaching the threshold of T2D, but it presents a high risk for its progression.

Prediabetes is also independently associated with other clinical outcomes.

Approximately 5%–10% of middle-aged adults with prediabetes go on to develop T2D each year. Throughout their lifetime, about 70% of those with prediabetes will eventually develop T2D.

In the U.S., as many as 96 million adults have prediabetes, which equates to about 38% of the adult population.

Research Methodology

To examine the risk of dementia-related to prediabetes, the researchers analyzed data from the Atherosclerosis Risk in Communities (ARIC) study.

The participants were aged 45–64 years in 1987–1989, originating from four U.S. counties. The researchers used the second visit of the study (1990–1992) as the baseline period for their analysis.

Cognitive function was assessed using a scoring system that incorporated three cognitive tests, an expanded neuropsychological ten-test collection, and an informant interview.

The Mini-Mental State Examination (MMSE) was also administered. Participants were followed until 2019.

Findings: Early-Onset Type 2 Diabetes Poses the Highest Dementia Risk

Of the 11,656 participants who didn’t have diabetes at the start of the study, 2,330 (20%) had prediabetes.

After accounting for diabetes developing after the baseline period, the researchers found no statistically significant link between prediabetes and dementia.

However, they discovered that the risk of dementia increased with an earlier age of T2D onset: those developing T2D before age 60 had a threefold increased risk of dementia.

This risk decreased to a 73% increase for those developing T2D between 60–69 years old, and a 23% increase for those developing T2D between 70–79 years old.

For those who developed T2D at 80 years or older, there was no associated increased risk of dementia.

The authors concluded, “Prediabetes is associated with dementia risk, but this risk is explained by the development of diabetes. Diabetes onset at an early age is most strongly related to dementia.

Thus, preventing or delaying the progression of prediabetes to diabetes will substantially reduce the future burden of dementia.”

If you care about diabetes, please read studies about leading cause of death in type 2 diabetes, and if you have diabetes, coffee and green tea may help you live longer.

For more information about diabetes, please see recent studies about Keto diet could help control body weight, blood sugar in type 2 diabetes and results showing that blueberries strongly benefit people with metabolic syndrome.

The study was published in Diabetologia.

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