Diabetes Drug May Protect the Brain
Study found patients taking metformin were 20 percent less likely to develop dementia
During the study, nearly 10 percent of the patients were diagnosed with dementia. (The study was not able to differentiate between Alzheimer's disease and other forms of dementia, Whitmer said.)
Compared to people taking sulfonylureas, those on metformin had a 20 percent decreased risk of developing dementia, according to the study. There was no difference in dementia risk for those on TZDs or insulin compared to those on sulfonylureas.
The researchers controlled the data for a number of factors, including age, duration of diabetes, blood sugar control, race and education, Whitmer said.
So what is it about metformin that might help protect the brain? Whitmer said one theory stemming from animal research is that metformin may play a role in the development of new brain cells (neurogenesis). It has also been linked to reduced inflammation, she added.
One expert was excited by the findings.
"Insulin promotes the survival of certain nerve cells. A drug like metformin, [which is] an insulin sensitizer in the body, may also be an insulin sensitizer in the brain," said Dr. Richard Lipton, director of the division of cognitive aging and dementia at Montefiore Medical Center in New York City. "We know that people with Alzheimer's lose brain volume, which may be a poor replacement of nerve cells. The notion that metformin might promote neurogenesis and brain cell replacement is a very attractive hypothesis."
"The idea that how we treat diabetes could affect all-cause dementia is very exciting," Lipton said.
Whitmer hopes to do more research to determine whether the long-term use of metformin would have an even greater effect, whether larger doses make a difference and whether there would be a difference in risk reduction based on the type of dementia.
For now, she said, it's important to remember this: "The brain isn't isolated. When you think about your brain health you should be thinking about whole body health, and think about it over your life course. Dementia shows up late in life, but those changes start a decade or more before they show up. What's good for the health of the heart is also what's good for the brain."