New research on dementia has found that smoking and diabetes aren’t just vaguely linked to health problems—they also may lead to build up of calcium deposits in the hippocampus, the brain’s memory center, according to a new study.
Dutch researchers looked at almost 2,000 patients with an average age of 78. They gave all of them cognitive tests and CT scans, which allowed them to see who had calcium build-up. They found that around 19 percent, or 380 people, had brain calcification in the hippocampus. Those same people had a strong likelihood of being smokers and/or diabetics.
The hippocampus plays an important role in the brain’s ability to store short- and long-term memories. It’s necessary for the formation of what’s known as episodic memories—the kind of memories that help you recall past personal experiences, like the birth of your child or a loved one’s wedding. Some scientists believe that the hippocampus is also responsible for transferring memories into long-term storage in the cerebral cortex. In dementia, these kinds of memories become inaccessible fairly early in the disease. Studies have shown that shrinkage of the hippocampus can actually predict dementia. In the brain scans of patients with mild cognitive impairment, which often leads to Alzheimer’s, a shrinking hippocampus sets them apart from people with normal cognitive abilities.
“We know that calcifications in the hippocampus are common, especially with increasing age,” said the study’s lead author, Esther J.M. de Brouwer, M.D., a geriatrician at the University Medical Center in Utrecht, the Netherlands. “However, we did not know if calcifications in the hippocampus related to cognitive function.”
In these patients, the scientists did not find a link between cognitive ability and calcification around the hippocampus, which they found surprising. But they have a possible explanation:
“The hippocampus is made up of different layers, and it is possible that the calcifications did not damage the hippocampal structure that is important for memory storage,” said de Brouwer. “Another explanation could be the selection of our study participants, who all came from a memory clinic.”
But that’s not to say that hippocampus calcifications are harmless. “In a recent histopathology study, hippocampal calcifications were found to be a manifestation of vascular disease,” said de Brouwer. Cardiovascular events like stroke and heart attack significantly increase the risk of dementia.
And while this study was observational and can’t directly link smoking and diabetes to calcifications or dementia, both are still considered risk factors for many reasons.
“It is well known that smoking and diabetes are risk factors for cardiovascular disease,” said de Brouwer. “It is, therefore, likely that smoking and diabetes are risk factors for hippocampal calcifications.”
This study was published in the journal Radiology.