Metformin, the first-line treatment for most cases of type 2 diabetes was found to be associated with slowing the cognitive decline, according to a recent observational study published in the journal Diabetes Care.
The study was led by researchers at the Garvan Institute of Medical Research and the Centre for Healthy Brain Ageing (CHeBA), UNSW Sydney. The study conducted over the course of six years in the Sydney Memory and Ageing Study in 1037 Australians (aged 70 to 90 years old at baseline), has revealed that individuals with type 2 diabetes who used metformin experienced slower cognitive decline with lower dementia rates than those who did not use the medication.
Type 2 diabetes occurs when the body can no longer produce enough insulin to meet its needs, leaving affected individuals unable to maintain blood glucose levels within a normal range. This can lead to long-term health complications, including cognitive decline.
“As they age, people living with type 2 diabetes have a staggering 60% risk of developing dementia, a devastating condition that impacts thinking, behaviour, the ability to perform everyday tasks, and the ability to maintain independence. This has immense personal, family, economic, and societal impacts,” said first author Professor Katherine Samaras, Leader of the Healthy Ageing Research Theme at the Garvan Institute and endocrinologist at St. Vincent’s Hospital Sydney.
The researchers of this study investigated data from participants of CHeBA’s Sydney Memory and Ageing Study. In this cohort, 123 study participants had type 2 diabetes, and 67 received metformin to lower blood sugar levels. The researchers tested cognitive function every two years, using detailed assessments that measured cognition over a number of capabilities, including memory, executive function, attention and speed, and language.
The findings revealed individuals with type 2 diabetes taking metformin had significantly slower cognitive decline and lower dementia risk compared to those not taking metformin. Remarkably, in those with type 2 diabetes taking metformin, there was no difference in the rate of decline in cognitive function over six years compared to those without diabetes.
Metformin works by reducing the amount of glucose released from the liver into the blood stream and allows the body’s cells to better respond to blood glucose levels.
“This study has provided promising initial evidence that metformin may protect against cognitive decline. While type 2 diabetes is thought to increase dementia risk by promoting degenerative pathways in the brain and nerves, these pathways also occur in others at risk of dementia, and it is possible insulin resistance may be the mediator,” said Professor Samaras.
To establish a definitive effect, the researchers are now planning a large, randomized controlled trial of metformin in individuals at risk of dementia and assess their cognitive function over three years.