Type 2 Diabetes & Brain Effects in Native Americans: What A New Study Suggests

A new study looked at how having diabetes may impact brain health in Native Americans.

The researchers found that the longer someone had diabetes, the more it affected their brain.

But other health issues like obesity did not appear to impact the brain as much.

Key facts:

The study involved 51 Native Americans with type 2 diabetes. Their average age was 48 years old.
They had diabetes for about 20 years on average. Most were obese.
Their thinking skills were similar to people without diabetes. But the longer they had diabetes, the worse their memory was.
The longer someone had diabetes, the thinner their brain’s outer layer and the smaller some brain areas were. These changes can harm thinking skills.
Kidney problems and nerve damage from diabetes also linked to less gray matter and more white spots in the brain.
But obesity did not relate to changes in the brain. This was surprising since obesity often affects thinking skills.
The results suggest diabetes may impact Native Americans’ brains more than obesity. This differs from other populations.

Source: Annals of Clinical and Translational Neurology 2023 Jul 30.

Studying Native Americans with high rates of diabetes

The study involved Native Americans from the Gila River Indian Community in Arizona.

This group has very high rates of obesity and type 2 diabetes that start at young ages.

The researchers wanted to see how diabetes, obesity and other health issues affect brain structure and thinking skills in this population.

Previous studies show that obesity and diabetes raise the risk of cognitive problems like memory loss and dementia.

But most research has been in older white adults.

Few studies have looked at younger minority groups with longstanding diabetes like the Native Americans in this study.

The study included 51 Native American adults from the Gila River tribe.

Their average age was 48 years old. About three-quarters were women.

They had type 2 diabetes for about 20 years on average. Most were obese.

Many also had high blood pressure, cholesterol and kidney problems, which often go along with diabetes.

The participants completed standard tests of memory, attention, thinking speed and other thinking skills.

About 45 people also had MRI brain scans. The scans measured different areas of gray and white matter, along with blood flow.

Gray matter contains neuron cell bodies and fuels thinking skills. White matter connects brain areas.

The scans also measured subtle changes like cortical thinning and white spots linked to cognitive problems.

The Native Americans with longstanding diabetes had thinking test scores similar to normal scores for their age and education level.

But diabetes duration did relate to some changes in the brain:

The longer someone had diabetes, the thinner their brain’s cortical layer was. The cortex is the outer shell important for cognition.
Diabetes duration also linked to having less gray matter overall and in deep subcortical areas.
Longer diabetes related to more white spots and damage in the brain’s white matter.
People who had diabetes longer did worse on a memory test. But diabetes duration did not affect other thinking tests.

These results are concerning since thinner cortex, less gray matter, and more white damage are tied to worse thinking and dementia.

Having obesity did not relate to differences in thinking scores in this group of Native Americans with longstanding diabetes.

Obesity also did not link clearly to abnormalities in gray matter, white matter or cortical thickness on the brain scans.

This differs from previous findings in other populations. Most research shows obesity harms cognitive function, especially in mid-life.

The reasons for this discrepancy are unclear. But it may be because diabetes duration had a bigger impact than obesity on the brain in this group.

The researchers also looked at whether diabetes complications linked to changes in gray matter, white matter or thinking skills.

Two complications showed relationships with brain abnormalities:

Kidney disease related to having less gray matter and more white matter damage.
Diabetic nerve damage also connected to less gray matter.

In contrast, vision problems from diabetes did not relate to differences in brain structure or thinking skills.

This study has a few important implications:

For Native Americans with lifelong diabetes, diabetes duration may affect the brain more than obesity. This contrasts with previous research in other populations.
Preventing or delaying kidney disease and nerve damage could help protect brain health in people with diabetes.
Groups with high diabetes rates may benefit from early screening for cognitive impairment. Catching it early allows for interventions and treatment planning.
The results support testing cognitive function in middle-aged adults with longstanding diabetes – not just elderly diabetes patients.
More research is needed in minority groups with high diabetes rates. This can unveil impacts on the brain and guide interventions to protect cognition.

In conclusion, this study reveals new insights into how diabetes relates to brain health in Native Americans.

The results highlight the need for early cognitive screening and prevention efforts in high-risk groups.

Catching cognitive problems early can improve outcomes and quality of life.

References

Study: Association between brain health outcomes and metabolic risk factors in persons with diabetes
Authors: Evan L Reynolds et al. (2023)