The Potential of Metformin in Preventing Dementia
For decades, metformin has been a cornerstone in the treatment of type 2 diabetes. This inexpensive drug, which has been used for about 100 years, helps regulate blood sugar levels by reducing the amount of glucose produced by the liver and improving the body’s response to insulin. It is the first-line treatment for more than 70 percent of people newly diagnosed with type 2 diabetes.
Doctors have long speculated that metformin might offer benefits beyond controlling blood sugar. Observational studies have suggested that this medication could also play a role in preventing dementia, although the evidence has been mixed. Some research indicated that metformin might worsen the development of Alzheimer’s disease, while others pointed to potential protective effects on the brain.
Now, a recent study from Taipei Medical University in Taiwan has added to the growing body of evidence supporting metformin’s potential as a preventive measure against dementia. Researchers found that among half a million overweight and obese individuals without diabetes, those who took metformin had a lower risk of developing dementia or dying from any cause, regardless of their BMI.
Obesity is a known risk factor for dementia, as it can weaken the body’s defenses against brain damage and contribute to chronic inflammation, which may harm nerve cells. Prior research into metformin’s effects on dementia prevention has largely focused on individuals with diabetes. However, the new study is the first to explore its potential in people with obesity using real-world data.
The researchers analyzed electronic health records from millions of patients across 66 U.S. healthcare systems, including hospitals, specialty centers, and clinics. They emphasized that the data reflects a diverse population, making the findings broadly applicable. The study included approximately 905,000 participants, evenly split into two groups: those taking metformin and those not.
Participants were matched based on age, health status, and other factors to ensure a fair comparison. Those in the metformin group had been prescribed the drug at least twice over a period of six months. While the study did not specify why individuals were prescribed metformin, the drug is used for more than just diabetes, including conditions like prediabetes, metabolic disorders, and polycystic ovary syndrome.
The participants were categorized into four groups based on their BMI: overweight (25–29.9), obese class I (30–34.9), obese class II (35–39.9), and morbidly obese (over 40). After following them for 10 years, the researchers observed that metformin users had a lower risk of developing dementia across all BMI categories.
The risk reduction varied slightly depending on weight, but two groups showed significant results. Individuals with a BMI of 30 to 34.9 had an 8% lower risk of dementia compared to non-users, while those with a BMI of 25 to 29.9 saw a 12.5% reduction. People with a BMI of 35 to 39.9 experienced a 4% lower risk, which was considered statistically insignificant due to a smaller sample size. There was no significant difference for those with a BMI over 40.
In addition to reducing dementia risk, metformin users also had a significantly lower risk of death from any cause across all BMI categories. The effect on mortality was stronger than on dementia risk. For example, individuals with a BMI of 25 to 29.9 had a 28% lower risk of death, while those with a BMI of 30 to 34.9 had a 27% lower risk.
These findings, published in the journal Diabetes, Obesity and Metabolism, highlight the potential of metformin as a tool for both managing diabetes and preventing cognitive decline. Scientists attribute these benefits to the drug’s anti-inflammatory and antioxidant properties, which may help combat the neuroinflammation associated with neurodegenerative diseases.
A 2020 study by Australian researchers further supported these claims. They followed over 1,000 seniors aged 70 to 90 in Sydney for up to six years, assessing their memory and thinking skills. The study found that individuals with type 2 diabetes who took metformin had an 81% lower risk of dementia compared to those with diabetes who did not take the drug. Additionally, brain scans and cognitive tests showed that metformin users experienced a slower decline in cognitive abilities, particularly in decision-making and overall brain function.
As research continues to uncover the broader benefits of metformin, its potential as a preventive measure for dementia and other age-related conditions becomes increasingly promising.
