From the American Academy of Neurology
SAN DIEGO—High serum calcium levels at hospital admission are associated with less severe strokes and result in improved functional outcomes at discharge, according to study results presented at the 2006 annual meeting of the American Academy of Neurology. These new data also support the ability of elevated extracellular calcium to prevent cell death.
In models of stroke, both calcium and magnesium have been shown to be intricately involved in the pathways of cell death. And studies have shown that high dietary intake of these minerals may reduce risk for stroke.
Included in this study were 240 consecutive patients (50% women; mean age, 60.1 years) presenting within 24 hours of ischemic stroke at the University of California Los Angeles (UCLA) Stroke Center over an 18-month period. Patients were categorized into quartiles based on total serum calcium and magnesium levels at admission. Stroke severity was measured using an admission National Institutes of Health Stroke Scale score; functional outcomes were based on modified Rankin Scale score at the time of hospital discharge.
Multivariate logistic regression model analysis controlled for potential confounding factors, including age, atrial fibrillation, premorbid statin or antithrombotic use, glucose level, blood pressure, temperature, and stroke subtype.
Strokes in patients with the highest calcium levels at the time of admission were one third as severe as those with the lowest levels. Highest calcium levels also correlated with a 50% to 70% lower risk of a poor functional outcome. Magnesium levels were unrelated to either stroke severity or outcome.
“The results suggest a connection between high calcium level in the blood and reduced cell death from stroke,” said lead investigator Bruce Ovbiagele, MD, of the UCLA Medical Center. “However, it is not yet known whether modifying dietary calcium in people at risk for stroke may help protect against poor stroke outcome.”
He told IMWR, “We were surprised by the magnitude of the effect. There are 2 issues here. Is this a primary effect or secondary effect of calcium? We are not sure if calcium is doing something to protect the brain, or is this just a marker of good health? Is this just a marker that people who eat well tend to have more resistant bodies that recover much better?”
Animal studies have demonstrated that calcium administration can reduce both infarct size and stroke-related mortality. Studies in cancer patients have suggested that higher levels of calcium in extracellular fluid may result in subtle changes in the intracellular second messenger system that initiate an antiapoptosis pathway.
Dr Ovbiagele said that further support for the role of calcium as a prognosticator are general medical studies showing that emergency room and critically ill patients with hypocalcaemia tend to have generally poorer clinical outcomes.