Correcting Vitamin D Deficiency May Bolster Cognition in MS – MedPage Today
CHICAGO — Supplementation with high-dose vitamin D may help improve cognition in patients with multiple sclerosis who have low blood levels of the vitamin, researchers reported here.
In a small study of Lebanese patients, those who were deficient in vitamin D had a significant improvement in scores on memory tests 3 months later, even after controlling for several potential confounders, Hala Darwish, PhD, of American University of Beirut, reported during a poster session at the Society for Neuroscience meeting here.
Changes weren’t significant, however, for three other cognitive tests — but Darwish said 3 months may not be long enough to see the effects of supplementation on cognitive function.
“There’s an overall improvement in memory at three months,” Darwish told MedPage Today. “Those who were supplemented performed better. Those who had low vitamin D started below the performance cutoff score, but after three months of supplementation, they actually came to the cutoff or above.”
Many researchers think that vitamin D plays role in the pathogenesis of multiple sclerosis, since sufficient levels of the vitamin are associated with decreased inflammation, improved function, and better cognitive performance.
Current therapies for MS have only a modest effect on cognitive decline in the disease, even though impaired cognition has an impact on morbidity and quality of life in this population — so it’s an area where vitamin D may be able to help, Darwish said.
“MS patients in general tend to have low vitamin D levels, so it makes a lot of sense for us to see if we can supplement them with high doses of the vitamin and see if that has any impact on cognitive performance,” she told MedPage Today.
To test that, the researchers assessed records from 88 MS patients treated at the American University of Beirut, who had either vitamin D deficiency — serum 25-hydroxyvitamin D (25[OH]D) levels of 25 ng/mL or less — or who had normal levels of the vitamin (35 ng/mL or higher).
Those who were vitamin D deficient were then supplemented with high-dose vitamin D — either 10,000 IU daily or 50,000 IU per week — for 3 months, while those with normal levels were given standard care.
Darwish and colleagues conducted a battery of cognitive tests at baseline and then again after 3 months, including the Arabic Montreal Cognitive Assessment (MOCA), the Stroop Test, the Symbol Digit Modalities Test (SDMT), and the Brief Visual Memory Test-Delayed Recall (BVMT-DR).
Overall, they found significantly improved performance for those supplemented with vitamin D on the BVMT-DR test after controlling for confounders including disease duration, disability as measured by EDSS scores, age, education, physical activity, smoking, alcohol, anxiety, and depression (P<0.04).
Although the findings weren’t significant for the other tests, Darwish reiterated that the study may need to go on for longer than 3 months in order to detect a statistically significant difference.
“We think vitamin D is actually a factor in cognitive performance,” Darwish told MedPage Today. “Three months might be too short of a duration, but we chose that because this is the first time we’re supplementing patients and that seemed to be the most logical shortest duration.”
She said the next step is to repeat the study over a longer duration, and to establish normative values of the cognitive tests for Arabic patients, particularly those in Lebanon. Darwish also wants to use more verbal tests, including the California Verbal Learning Test, which she said her group is currently translating and validating in a Lebanese cohort.
Although the study does not have immediate clinical implications, she said, many neurologists may be comfortable prescribing vitamin D supplementation to their MS patients who have a deficiency in the vitamin.
“Some clinicians will be advocates of supplementation, but others are not because there aren’t enough clinical trials,” Darwish said. “But I know the neurologists I work with are highly for supplementation, since vitamin D is associated with reduced inflammation and that could be important in MS given the role of inflammation.”
She added that the findings could have implications beyond multiple sclerosis.
“We have vitamin D receptors in the brain and the hippocampus, which suggests a function in cognition,” she said. “So I don’t think it applies only to MS patients. I think it applies to any patient with cognitive impairment and vitamin D deficiency.”
Darwish disclosed no relevant financial relationships with industry.
F. Perry Wilson, MD, MSCE Assistant Professor, Section of Nephrology, Yale School of Medicine