LONDON — Taking a common diabetes medication can cut the risk of Alzheimer’s by more than a fifth, according to new research. Known as TZDs (thiazolidinediones), researchers say they boost blood flow by reducing bad cholesterol, increasing oxygen supply to the brain.
A study of more than half a million patients found those taking TZDs were 22 percent less likely to develop the neurological disease. People with Type 2 diabetes are more vulnerable to dementia, studies indicate. Both conditions have a link to poor blood circulation.
“Type 2 diabetes is associated with elevated risk of all cause dementia, including its two main subtypes, Alzheimer’s disease and vascular dementia (VaD),” says lead author Dr. Jin Zhou from the University of Arizona, according to a statement from SWNS.
Patients take these tablets once or twice daily with or without food. They work by targeting insulin resistance, enabling the hormone to improve glucose control. By reducing the body’s resistance to insulin, the hormone is able to work more effectively at improving glucose control. They also lower blood pressure.
The U.S. Food and Drug Administration has approved of two TZDs, rosiglitazone and pioglitazone, for the treatment of Type 2 diabetes.
How do TZDs compare to other drugs?
The findings are based on electronic health records of 559,106 people in the national Veteran Affairs (VA) Health System diagnosed with Type 2 diabetes between January 2000 and December 2019. In the most extensive study of its kind, Dr. Zhou and colleagues tracked these veterans for an average of almost eight years.
Specifically, cases of Alzheimer’s and vascular dementia fell by 11 and 57 percent respectively among those taking TZDs. This was compared to peers receiving alternative diabetes medications, including metformin or a class of drugs called sulfonylureas.
The findings open the door to repurposing TZDs to fight dementia. After at least one year of treatment, TZD use led to a 22-percent lower risk of dementia, compared to those using metformin.
“Vascular diseases increase the risk of Alzheimer’s, so TZD’s reduction in VaD may also reduce Alzheimer’s development,” Dr. Zhou tells SWNS. “Some studies comparing TZD with either placebo or standard care within patients with type 2 diabetes have reported reduced risk of Alzheimer’s.”
Further analysis showed people under 75 benefited most, highlighting the importance of early prevention for dementia. One of the reasons drug trials have failed to date is because doctors prescribe medication after the disease takes hold. They also appeared to be more protective in overweight or obese participants, the study finds.
“This may result as TZD reduces central obesity, a recognized risk factor for dementia,” researchers say, according to SWNS.
Sulfonylureas could make dementia worse
Interestingly, those taking sulfonylureas were 12 percent more likely to develop dementia than those on metformin.
“In summary, TZD users had a lower risk of dementia, and SU users had a higher risk of dementia than MET users,” Dr. Zhou says. “Future studies for repurposing oral anti-diabetic agents for dementia prevention may consider prioritizing TZDs. SUs users could be at an elevated risk of dementia, compared with MET or TZD users. Thus, monitoring cognitive functions regularly is more important to this population. Supplementing SU with either MET or TZD may partially offset its pro-dementia effects.
“These findings may help inform medication selection for [older] patients with [type 2 diabetes] at high risk of dementia,” the team concludes in a media release.
The study is published in the journal BMJ Open Diabetes Research & Care.
South West News Service writer Mark Waghorn contributed to this report.