New research reveals an unexpected link between diabetes medications and dementia risk, while antibiotics and other common drugs may protect against cognitive decline in aging adults.
At a Glance
- Type 2 diabetes significantly increases dementia risk, with Alzheimer’s sometimes called “Type 3 diabetes” due to similar insulin resistance issues
- Certain diabetes medications show promise in reducing dementia risk, with thiazolidinediones (TZDs) offering 22% lower risk compared to metformin
- Antibiotics, antivirals, vaccines, and anti-inflammatory drugs are associated with reduced dementia risk, supporting the infectious trigger hypothesis
- Repurposing existing medications could accelerate dementia treatment developments, potentially saving decades of research and millions in costs
The Diabetes-Dementia Connection
Diabetes has become one of America’s leading causes of death, with an epidemic fueled by an aging and increasingly overweight population. While advances in diabetes treatment have successfully reduced traditional complications like blindness and kidney failure, doctors are now observing a rise in non-traditional complications including cancer, infections, and dementia. The connection between diabetes and cognitive decline is particularly concerning for older adults managing both conditions, prompting researchers to investigate this relationship more deeply.
The shared biological mechanisms between Type 2 diabetes and Alzheimer’s disease have led some researchers to label Alzheimer’s as “Type 3 diabetes.” Both conditions feature insulin resistance, chronic inflammation, and vascular complications. Insulin resistance affects not only the body’s ability to process glucose but also impacts brain function, potentially accelerating cognitive decline. The overlapping risk factors include obesity, high blood pressure, and physical inactivity, suggesting that metabolic health directly influences brain health.
Diabetes Medications Show Promise for Brain Protection
Recent studies have uncovered promising evidence that certain diabetes medications may offer protection against dementia. A comprehensive study of US veterans aged 60 and above with Type 2 diabetes found significant differences in dementia risk based on medication type. Thiazolidinediones (TZDs) were associated with a 22% lower risk of all-cause dementia compared to metformin, while sulfonylurea (SU) monotherapy increased dementia risk by 12% compared to metformin therapy.
GLP1 receptor agonists and SGLT2 inhibitors—newer diabetes medications—are showing particular promise in potentially combating Alzheimer’s disease. These medications improve cognitive function in laboratory studies and reduce inflammation while promoting beneficial changes in metabolism. With the biological overlap between diabetes and dementia becoming clearer, managing blood sugar effectively may be an important strategy for preserving cognitive health as we age.
Unexpected Protection: Antibiotics and Common Medications
In a surprising development, researchers have discovered that commonly prescribed drugs—including antibiotics, antivirals, and certain vaccines—are associated with a lower risk of developing dementia. This finding contradicts earlier concerns that antibiotic use might increase dementia risk by disrupting gut bacteria. A large study involving 13,571 dementia-free participants found no increased dementia risk among those who had taken antibiotics compared to those who hadn’t, even after five years of follow-up.
Anti-inflammatory medications, particularly NSAIDs like ibuprofen, appear to protect against memory decline by blocking inflammation in the brain. Additionally, specific vaccines including those for hepatitis A, typhoid, and diphtheria were linked to lower dementia risk, as was the BCG vaccine, which protects against tuberculosis. These findings support the hypothesis that some forms of dementia may have infectious triggers, and that medications targeting infectious agents or inflammation could play a role in prevention.
Repurposing Existing Medications: A Faster Path to Treatment
With global dementia cases expected to nearly triple to 153 million by 2050, researchers are looking for efficient solutions. Progress in developing new dementia drugs has been painfully slow, with recent medications like lecanemab and donanemab showing only modest benefits. Repurposing existing medications could dramatically accelerate the path to effective dementia treatments, as these drugs have already been proven safe for human use.
The UK government is supporting an Alzheimer’s trial platform to evaluate potential dementia treatments rapidly and efficiently, including repurposed medications. This approach could save decades of research time and millions in development costs. For adults concerned about cognitive health, these findings suggest multiple pathways to potentially reduce dementia risk—from careful diabetes management to discussing appropriate preventive medications with healthcare providers.
Sources:
Unlocking the Diabetes and Dementia Connection for Better Health
The Science Behind Antibiotics, Vaccines, and Lower Dementia Risk
