Smoking and Diabetes Linked to Brain Calcifications
Older age also associated with increased risk of hippocampal calcifications on CT images
People who smoke or have diabetes may be at increased risk of hippocampal calcifications according to a new study in Radiology.
Researchers have hypothesized that abnormal buildups of calcifications in the hippocampus may be related to vascular problems that could contribute to hippocampal atrophy and subsequent cognitive deterioration. However, published research on the association between hippocampal calcification and cognitive impairment is limited.
“We know that calcifications in the hippocampus are common, especially with increasing age,” said the study’s lead author, Esther J.M. de Brouwer, MD, 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.”
Dr. de Brouwer and colleagues studied the association between vascular risk factors like high blood pressure, diabetes and smoking and hippocampal calcifications.
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 (odds ratio [OR], 1.05), diabetes (OR, 1.50) and smoking (OR, 1.49) were risk factors associated with the presence of hippocampal calcifications.
The number of risk factors each patient had was associated with the severity of hippocampal calcifications. In patients with moderate or severe calcifications, 17.0 percent had two risk factors and 3.1 percent had three risk factors, while those without hippocampal calcifications or with mild calcifications, only 11.1 percent had two risk factors and 0.5 percent had three risk factors.
Research Reveals Surprising Findings
While the study was not designed to conclusively determine if smoking and diabetes increase the risk of hippocampal calcifications, the results strongly suggest a link.
“We do think that smoking and diabetes are risk factors,” Dr. de Brouwer said. “In a recent histopathology study, hippocampal calcifications were found to be a manifestation of vascular disease. It is well known that smoking and diabetes are risk factors for cardiovascular disease. It is, therefore, likely that smoking and diabetes are risk factors for hippocampal calcifications.”
There was no link between the presence and severity of hippocampal calcifications and cognitive function; a surprising finding, according to Dr. de Brouwer, with several possible explanations.
“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.”
The development of the multiplanar brain CT scans has enabled better distinction between hippocampal calcifications and calcifications in nearby brain structures, according to researchers.
Web Extras
- Access the study, “Hippocampal Calcifications: Risk Factors and Association with Cognitive Function,” at https://pubs.rsna.org/doi/full/10.1148/radiol.2018172588