London, June 13: People who smoke or have diabetes may be at a high risk of developing abnormal deposits of calcium in the brain region crucial to memory, a study has found. Dementia is a major public health problem that affects tens of millions of people worldwide. One focus of dementia research has been the hippocampus, a brain structure important for both short- and long-term memory storage. Alzheimer's disease, the most common type of dementia, is associated with atrophy of the hippocampus.

Researchers have anticipated that calcifications or abnormal buildups of calcium in the hippocampus region of the brain may be related to vascular problems, that could contribute to hippocampal atrophy and subsequent cognitive deterioration. "We know that calcifications in the hippocampus are common, especially with increasing age," said Esther J M de Brouwer, from University Medical Center in Utrecht in The Netherlands. "However, we did not know if calcifications in the hippocampus related to cognitive function," she added.

Researchers studied the association between vascular risk factors like high blood pressure, diabetes and smoking and hippocampal calcifications. While the study was not designed to conclusively determine if smoking and diabetes increase the risk of hippocampal calcifications, the results suggest a link.

"In a recent histopathology study, hippocampal calcifications were found to be a manifestation of a vascular disease. It is well known that smoking and diabetes are risk factors for cardiovascular disease," De Brouwer said. "It is, therefore, likely that smoking and diabetes are risk factors for hippocampal calcifications," she said.

The development of the multiplanar brain CT scans has enabled better distinction between hippocampal calcifications and calcifications in nearby brain structures, according to researchers. "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," she said. "Another explanation could be the selection of our study participants, who all came from a memory clinic," she added.

The study group included 1,991 patients, average age 78 years, who had visited a memory clinic at a Dutch hospital between 2009 and 2015. The patients had a standard diagnostic workup including cognitive tests and multiplanar brain CT scans. The researchers analyzed the CT scans for the presence and severity of hippocampal calcifications. Of the 1,991 patients, 380, or 19.1 percent, had hippocampal calcifications. Researchers found that older age, diabetes and smoking were risk factors associated with the presence of hippocampal calcifications.