Drugs for type 2 diabetes can reduce the risk of dementia and Parkinson's by 22%

• Type 2 diabetes is associated with an increased risk of Alzheimer's and Parkinson's.
• According to a new study, certain diabetes medications can significantly reduce this risk.
• These drugs, called gliflozines or SGLT2 Inhibitors prevent the kidneys from reabsorbing too much blood sugar, thereby improving blood sugar levels.
• Although the results of the study are encouraging, the authors call for further research to confirm their findings.

A team of scientists in Korea recently studied a group of diabetes drugs called gliflozins, or sodium-glucose cotransporter 2 (SGLT2) inhibitors.

They wanted to find out whether these drugs could reduce the risk of neurodegenerative diseases in people with type 2 diabetes (T2D).

Their analysis found that those taking gliflozin had the following compared to people taking other diabetes medications:

• 19% lower risk of developing Alzheimer’s disease
• 20% lower risk of developing Parkinson’s disease
• 31% lower risk of developing vascular dementia

The study appeared in the online edition of neurology on September 18th.

“The results are generally consistent, even after adjusting for factors such as blood pressure, glucose, cholesterol and kidney function,” said study author Minyoung Lee, MD, of Yonsei University College of Medicine in South Korea, in a press release.

For this study, researchers accessed data from 358,862 participants with type 2 diabetes and followed them for an average of 9.6 years.

At the end of the study, 6,837 participants had either dementia or Parkinson's disease.

Overall, taking gliflozin was associated with a 22 percent lower risk of developing dementia or Parkinson's disease.

When researchers broke down the risk of certain neurodegenerative diseases, they found that Alzheimer's risk was reduced by 19%, Parkinson's risk by 20%, and the risk of vascular dementia by 31%.

Daniel Truong, MD, neurologist and medical director of the Truong Neuroscience Institute at MemorialCare Orange Coast Medical Center in Fountain Valley, CA, and editor-in-chief of Journal of Clinical Parkinsonism and Related Disordersshared his thoughts on the study results with Healthline.

He said he was surprised “at how consistent the benefits were across different patient subgroups, including those with different comorbidities such as cardiovascular disease or high blood pressure.” Truong was not involved in the study.

Gliflozins, or SGLT2 inhibitors, work by preventing the kidneys from reabsorbing as much glucose. This allows the body to excrete the glucose in the urine rather than letting it re-enter the blood.

SGLT2 inhibitors are considered second-line drugs. In other words, doctors are more likely to prescribe them when a current diabetes medication is not working well enough.

Recently, there has been growing interest in this class of drugs and their protective effects against neurodegenerative diseases.

For example, another Korean study published last month concluded that taking gliflozin was associated with 35% lower risk the development of dementia compared to taking another common diabetes medication.

The latest study followed a similar approach, but also examined the effects of gliflozines on Parkinson's disease.

In addition, the scientists compared gliflozin with a number of other diabetes medications and not just with the single comparison drug in the previous study.

However, in type 2 diabetes, insulin resistance can occur, meaning that cells no longer respond adequately to insulin and do not absorb glucose as efficiently.

There is growing evidence that insulin resistance in the brain plays an important role in neurodegenerative diseases. When blood sugar levels rise, sensitive brain cells can be damaged.

A recent Meta-analysisFor example, it was found that diabetes is associated with a significantly higher risk of developing dementia.

Likewise, people with type 2 diabetes have a 21% increased risk of developing Parkinson's disease. There is also evidence that the disease may progress more quickly in people with type 2 diabetes.

“An appropriate response to insulin is important not only for the pancreas and many organs in the body, but also for the brain,” explained Dr. Alvaro Pascual-Leone, professor of neurology at Harvard Medical School and chief medical officer and co-founder of Linus Health. Pascual-Leone was not involved in the study.

“Insulin resistance may play a key role in the link between type 2 diabetes and Alzheimer’s disease, as well as other causes of dementia,” he told Healthline.

As the number of people with diabetes increases, many people may be at higher risk of developing neurodegenerative disease as they age.

While the study authors suggest that gliflozines may only slow the progression of neurodegeneration but not completely stop it, this would still provide significant benefits to the aging population.

However, the study does have some limitations. The researchers point out that these neurodegenerative diseases take many years to develop, so some people who did not have dementia or Parkinson's during the study may develop these diseases later.

“Further research is needed to confirm the long-term validity of these findings,” Lee said.

The study also leaves some questions unanswered.

For example, the authors wonder whether starting treatment with gliflozines earlier might further reduce the risk of neurodegeneration. This could be another reason why it is best to start treatment as early as possible.

In addition, the researchers found that the combination of metformin with gliflozines reduced the risk of Parkinson's disease and dementia more than any other drug combination.

This raises the tantalizing possibility that drug combinations may be even more effective.

“To optimize the use of antidiabetics in clinical practice in neurodegenerative diseases, future research should investigate the synergistic relationship between [gliflozins] with various combination therapies,” the authors write.

It is currently unclear whether gliflozins can also reduce the risk of neurodegenerative diseases in people without type 2 diabetes.

“More research is needed to determine whether gliflozines can be neuroprotective and improve brain health and reduce dementia in people without diabetes,” said Clifford Segil, a neurologist at Providence Saint John's Health Center in Santa Monica, California, who was not involved in the study.

“Given their widespread use, it should be clear within a decade whether this is true. We may know the answer by 2035,” Segal added.

Truong noted that these drugs “have the potential to form the basis for future dementia drugs, particularly for people at increased risk of developing dementia.”

“Their ability to improve brain metabolism, reduce inflammation and protect cardiovascular health is consistent with the primary risk factors and mechanisms that cause dementia,” he continued.

“These significant effects on reducing the risk of dementia and neurodegenerative diseases represent an exciting development in diabetes treatment with broader public health implications,” concluded Truong.