NASHVILLE—A low level of vitamin D independently predicts a large infarct volume and a poor outcome after ischemic stroke, according to a study described at the 2015 International Stroke Conference. “Though causality remains to be proven, our results highlight the need to further explore vitamin D as a promising biomarker for cerebral ischemic vulnerability and a potential target for stroke prevention,” said Nils Henninger, MD, Assistant Professor of Neurology and Psychiatry at University of Massachusetts Medical School in Worcester.
The prevalence of vitamin D insufficiency in Western countries is high, and low levels of vitamin D have been associated with neurovascular injury. “Many of the people we consider at high risk for developing stroke have low vitamin D levels,” said Dr. Henninger. “Understanding the link between stroke severity and vitamin D status will help us determine if we should treat vitamin D deficiency in these high-risk patients.”
Dr. Henninger and colleagues conducted a data analysis to assess whether low serum 25-hydroxyvitamin D (25[OH]D) predicts ischemic infarct volume and whether it relates to a worse outcome after stroke.
The investigators retrospectively analyzed data for 96 consecutive patients with acute ischemic stroke who were evaluated prospectively between January 2013 and January 2014 at a tertiary referral center. MRI confirmed the diagnosis of acute ischemic stroke for all patients. The researchers used multivariable linear and logistic regression analyses to test whether vitamin D independently predicts infarct volume and poor 90-day outcome, which was defined as a modified Rankin Scale score of greater than 2.
Dr. Henninger’s group found a significant inverse correlation between infarct volume and serum 25(OH)D concentration in patients with lacunar and nonlacunar infarcts. Patients with serum 25(OH)D concentrations of 30 ng/mL or greater had smaller infarct volumes than participants with concentrations less than 30 ng/mL. The association of 25(OH)D levels with ischemic infarct volume was independent of other known predictors of the infarct extent. After adjustment, lower vitamin D (trichotomized as ≥ 30 ng/mL vs 29–20 ng/mL vs < 20 ng/mL) was associated with a poor 90-day outcome.
A limitation of the study is that most of the participants were Caucasian. The results thus might not be applicable to other ethnic groups. “It’s too early to draw firm conclusions from our small study, and patients should discuss the need for vitamin D supplementation with their physician,” said Dr. Henninger. “However, the results do provide the impetus for further rigorous investigations into the association of vitamin D status and stroke severity. If our findings are replicated, the next logical step may be to test whether supplementation can protect patients at high risk for stroke.”
—Erik Greb