Type 2 diabetes and prediabetes are associated with accelerated brain ageing, according to a new study from Karolinska Institutet published in the journal Diabetes Care.

Way #1: Healthy Lifestyle’s Effects

The good news is that this may be counteracted by a healthy lifestyle.

Type 2 diabetes is a known risk factor for dementia, but it is unclear how diabetes and its early stages, known as prediabetes, affect brain ageing in people without dementia. Now, a comprehensive brain imaging study shows that both diabetes and prediabetes can be linked to accelerated brain ageing. 

The study included more than 31,000 people between 40 and 70 years of age from the UK Biobank who had undergone a brain MRI scan (magnetic resonance imaging). The researchers used a machine learning approach to estimate brain age in relation to the person’s chronological age.

Early warning sign for dementia

Prediabetes and diabetes were associated with brains that were 0.5 and 2.3 years older than chronological age, respectively. In people with poorly controlled diabetes, the brain appeared more than four years older than chronological age. The researchers also noted that the gap between brain age and chronological age increased slightly over time in people with diabetes. These associations were attenuated among people with high physical activity who abstained from smoking and heavy alcohol consumption.

“Having an older-appearing brain for one’s chronological age can indicate deviation from the normal ageing process and may constitute an early warning sign for dementia,” says the study’s lead author Abigail Dove, a PhD student at the Aging Research Center at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet. “On the positive side, it seems that people with diabetes may be able to influence their brain health through healthy living.”

Prevent cognitive impairment

Repeated MRI data were available for a small proportion of the study participants. Follow-up MRI scans are ongoing and researchers are now continuing to study the association between diabetes and brain ageing over time.

“There’s a high and growing prevalence of type 2 diabetes in the population,” says Abigail Dove. “We hope that our research will help prevent cognitive impairment and dementia in people with diabetes and prediabetes.”

Way #2: New Diabetes Drug Could Lower Dementia Risk by 35%

A recent study has found that a drug used to treat Type 2 diabetes might also help reduce the risk of dementia by 35%. This discovery is exciting because it offers a potential new way to protect our brains as we age.

This discovery is also exciting because dementia is becoming a major economic issue. Research shows health and social costs linked to dementia already exceed $1tn (£780bn) a year. If that number could be lowered by lowering the risk of dementia nationally, it would be a true game-changer.

What’s the Drug?

The drug type is called an SGLT2 inhibitor. This type of drug is used to improve high blood glucose levels in adults with Type 2 diabetes. This name is short for sodium-glucose cotransporter-2 (SGLT-2) inhibitor.

Approved medicines in the SGLT2 inhibitor class include:

• Brenzavvy™ (bexaglifloxin)
• Invokana® (canagliflozin)
• Farxiga® (dapagliflozin)
• Jardiance® (empagliflozin)
• Steglatro® (ertugliflozin)

Jardiance® (empagliflozin) has the highest SGLT2 specificity among all the clinically used or currently tested SGLT2 inhibitors.

The Connection

Type 2 diabetes and dementia share some common risk factors, like poor blood sugar control and inflammation. The drug in question helps manage these issues, which might explain its protective effect on the brain.

The Study

Korean researchers analyzed data from patient records of more than 220,000 people with type 2 diabetes. The patients were aged between 40 and 69 and their records were part of the Korea National Health Insurance Service. None of the patients had dementia at the start of the study.

Type 2 diabetes is one of 14 risk factors associated with a greater risk of developing dementia. Other factors include:

• high levels of bad cholesterol,
• untreated vision loss,
• hearing impairment,
• high blood pressure,
• smoking,
• obesity and
• physical inactivity.

Clear Conclusions

While previous studies have suggested SGLT-2 inhibitors could have a protective effect against dementia for older patients, until now, any protective effect on younger people and specific types of dementia such as Alzheimer’s disease and vascular dementia has been unclear.

Now, with 1,172 of the patients identified with newly diagnosed dementia during the study, there are hard numbers from which researchers can draw these clear and crucial conclusions.

The study also associated these patients with a 39% reduced risk for Alzheimer’s disease and a 52% reduced risk for vascular dementia.

Researchers are continuing to study this connection to understand how the drug works and who might benefit the most.