A common medicine used in the treatment of diabetes can reduce the risk of Alzheimer’s by almost a fifth, according to a new study.
Research published in the BMJ Open Diabetes Research & Care journal found that thiazolidinediones, commonly known as TZDs, can increase oxygen supply to the brain.
Experts review health records of 559.106 adults in the US who were diagnosed with type 2 diabetes between January 2000 and December 2019.
They found that of those taking TZDs, 22 per cent were less likely to develop Alzheimer’s.
Alzheimer’s disease is the most common cause of dementia – an ongoing decline of brain functioning – in the UK. The disease worsens the memory, thinking skills and other mental abilities. Around 900,000 people in the UK suffer from dementia.
Diabetic patients typically take TZDs twice a day, with or without food. The medicine works by targeting insulin resistance and increases ability to improve glucose control in the body.
But the study found that the medicine can also reduce bad cholesterol in the blood, lower blood pressure, and boost blood flow.
Experts said the findings were significant given that people with type 2 diabetes are more vulnerable to dementia, as both conditions have been linked to poor blood circulation.
Dr Jin Zhou from the University of Arizona, a lead author of the study, commented: “Type 2 diabetes is associated with elevated risk of all cause dementia, including its two main subtypes, Alzheimer’s disease and vascular dementia.”
In the UK, patients have been prescribed TZDs under the brand name Actos for more than 20 years.
Researchers tracked patients for an average of almost eight years and found that cases of Alzheimer’s and vascular dementia fell between 11 and 57 per cent in those taking TZD.
The patients were compared to others receiving alternative diabetes medications – such as metformin or sulfonylureas.
After at least one year of treatment, TZD was found to be associated with a 22 per cent lower risk of dementia, compared with the use of metformin.
Zhou said: “Vascular diseases increase the risk of Alzheimer’s, so TZD’s reduction in vascular dementia may also reduce Alzheimer’s development.
“Some studies comparing TZD with either placebo or standard care within patients with type 2 diabetes have reported reduced risk of Alzheimer’s.”
Analysis showed that TZDs were more effective in boosting blood circulation in those under the age of 75, and in overweight or obese patients.
“This may result as TZD reduces central obesity, a recognised risk factor for dementia,” Zhou said.
However, the study also found that those taking sulfonylureas were 12 per cent more likely to develop dementia than those taking metformin.
“In summary, TZD users had a lower risk of dementia, and sulfonylureas users had a higher risk of dementia than metformin users,” Zhou concluded.
“Future studies for repurposing oral anti-diabetic agents for dementia prevention may consider prioritising TZDs.”
