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- A new study investigates the relationship between specific diabetes drugs and dementia.
- They used data from more than 92,000 people with type 2 diabetes.
- The scientists found that two medications significantly reduce the risk of developing dementia in life.
A new study, published in JAMA Neurology, finds that people with type 2 diabetes who take two common anti-diabetes medications had a reduced risk of Alzheimer’s and associated dementias.
The drugs in question were glucagon-like peptide-1 receptor agonists (GLP-1RAs), like Ozempic and Wegovy, and sodium-glucose cotransporter-2 inhibitors (SGLT2is), like Jardiance.
Specifically, GLP-1RA was linked to a 33% lower risk of dementia, and SGLT2i was linked to a 43% lower risk. Other diabetes medications, however, were not associated with a change in risk.
How are dementia and diabetes linked?
As the average age of the population steadily rises, the number of dementia cases rises in step. Despite decades of intensive research, a cure remains elusive. Although some treatments can slow progress, we are far from a breakthrough.
Adding to these challenges, if an effective drug were found, it would take many years to build up a sufficient evidence base and millions of dollars to bring it to market.
For these reasons, some researchers are focusing on existing drugs. If they can identify a drug that is already widely used and helps lower the risk of dementia, it would be a much shorter road to wider availability.
Some recent research has suggested that type 2 diabetes and dementia may share some physiological similarities, including inflammation and impaired insulin signalling in the brain. People with diabetes also have a higher risk of developing dementia.
This raises an interesting question: If a drug reduces the impact of type 2 diabetes, might it also reduce the risk of dementia? Scientists have now investigated this question, and some evidence does suggest that diabetes medication may reduce dementia risk.
However, as the authors of the latest study explain, we need more evidence. To build the clearest picture to date, they used “a more rigorous methodological approach and robust adjustment for confounding factors.”
Drugs like Ozempic linked to 33% lower dementia risk
To investigate, the scientists accessed data from Florida, Georgia, and Alabama. In total, this amounted to 92,160 people aged 50 or older with type 2 diabetes.
Participants were followed until they died or developed dementia, including Alzheimer’s, vascular dementia, frontotemporal dementia, and Lewy body dementia.
They focused on three comparisons:
- GLP-1RA versus other second-line glucose-lowering drugs
- SGLT2i versus other second-line glucose-lowering drugs
- GLP-1RA versus SGLT2i.
The scientists concluded that GLP-1RAs and SGLT2is were associated with a reduced risk of developing dementias compared with second-line diabetes drugs.
“GLP-1RA use was associated with a 33% lower risk of [dementia], while SGLT2i use was associated with a 43% lower risk compared with other [glucose-lowering drugs],” the authors write.
Medical News Today contacted William Kapp, MD, a longevity expert and CEO of Fountain Life, not involved in tis study.
Kapp shared his thoughts on the findings, saying:
“The results didn’t shock me — but they did give more credence to what we’ve been observing. Brain and body don’t age separately. Metabolic problems such as insulin resistance are linked to inflammation, oxidative stress, and altered blood flow — all of which impact brain health.”
How do these drugs reduce dementia risk?
Although scientists do not know for sure how GLP-1RA and SGLT2i may reduce dementia risk in people with type 2 diabetes, the authors suggest some potential mechanisms.
For instance, GLP-1RAs have been shown to:
- reduce neuroinflammation
- improve insulin signalling in the brain
- promote the growth of new nerve cells (neurogenesis).
Similarly, SGLT2is may protect the brain by:
- improving cerebral blood flow
- reducing oxidative stress
- enhancing mitochondrial activity.
The scientists also explain that both drugs are associated with improved metabolic and vascular health, both of which may support healthy brain function.
Additionally, there is some evidence that these drugs can reduce levels of amyloid-beta and tau proteins in the brain — the hallmarks of Alzheimer’s disease.
Speaking with the Science Media Center, Prof. David Strain,MD, FRCP, associate professor of cardiometabolic health at the University of Exeter Medical School in the United Kingdom, similarly not involved in the study, explained that:
“GLP-1 receptor antagonists and SGLT-2 inhibitors have been demonstrated to control the sugar, and also reduce the inflammation (a key driver of Alzheimer’s disease) and reduce vascular risk (a key driver of vascular dementia) more than would be expected by the sugar control alone.”
“It is therefore no surprise that these data show a lower risk of dementia in people who receive them as part of her routine care,” Strain continued.
Do we have enough data to draw strong conclusions?
This study, which analyzed data from almost 100,000 people is supported by a number of previous studies. However, a paper published in the same journal and on the same day casts a small portion of doubt on the results.
The paper in question, also published in JAMA Neurology, is a systematic review and meta-analysis of 26 clinical trials including data from 164,531 participants.
According to its authors, “glucose-lowering therapy with GLP1-RAs, but not SGLT2is, was associated with a statistically significant reduction in dementia or cognitive impairment.”
So, their conclusions on GLP1-RAs mirror those from the original paper, but they did not find the same effect for SGLT2is. This may be partly due to the short duration of follow-up. The average study follow-up in the meta-analysis and the follow-up in the original study were under 5 years.
As dementia takes many years to develop, this may not be long enough.
“It’s still early, and we’re still not seeing all the long-term data,” Kapp told MNT. But what we’re seeing is that regulating insulin and inflammation might also slow down some of the changes in the brain tied to dementia.”
The inevitable next question is: Will these drugs reduce dementia risk in people without diabetes?
“If the benefit is from reducing insulin resistance or inflammation, it’s possible that these drugs could be good for people without diabetes,” Kapp told MNT before injecting some caution.
“Just because something is good for one group doesn’t mean it is for others. And there are always risks to long-term use,” he warned.
For now, the jury is — at least in part — out. We may have to wait for longer studies before we can draw solid conclusions. Still, it is looking increasingly likely that GLP1-RAs might reduce the risk of dementia for people with type 2 diabetes, which is certainly a positive finding.
