Pauline Anderson

October 09, 2015

BARCELONA — Patients with multiple sclerosis (MS) given vitamin D supplements showed improved cognition at 3 months, a new study shows.

The results suggest that patients with MS should get their vitamin D levels checked and, if deficient, take vitamin D supplements, said Hala Darwish, PhD, a neuroscience expert whose research at the American University of Beirut (AUB) focuses, among other things, on cognitive and inflammatory changes associated with aging.

"I'm one of those who believes that MS patients should take supplements," Dr Darwish told Medscape Medical News.

She presented results of the study here at the Congress of the European Committee for Treatment and Research in MS (ECTRIMS) 2015.

Brain Receptors

Vitamin D, which can be obtained through exposure to the sun or fortified foods, plays a role in the pathogenesis of MS, said Dr Darwish. It has been shown to improve physical function and decrease inflammation. Evidence also links vitamin D to cognitive performance in older adults.

That vitamin D affects cognition makes some biological sense, "We know there are vitamin D receptors in the brain" of both animals and humans, said Dr Darwish. "This suggests a function in cognition."

For the study, researchers recruited adult patients with MS from the AUB center who were being treated with interferon β. From blood tests, they determined that 88 patients qualified for inclusion in that they had normal serum 25-hydroxyvitamin D (25[OH]D) levels (>35 μg/mL) or were vitamin D deficient (<25 μg/mL).

Researchers collected demographic data, health history, and information on lifestyle habits. They assessed depression and anxiety using the Arabic-Hopkins Symptoms Checklist.

The low and normal vitamin D groups were similar in terms of marital status, income, and employment level. Dr Darwish noted that both groups were highly educated, with many having at least a college degree.

As for lifestyle, those with low vitamin D engaged in less physical activity than the normal vitamin D group, and they smoked more and drank more alcohol. This low vitamin D group also tended to participate in fewer leisure activities.

Disease duration did not differ between the groups, but there was a significant difference on the Expanded Disability Status Scale (EDSS), with those in the low vitamin D group having a higher mean score (1.6 vs 1.1; P = .04).

This, said Dr Darwish, might explain their differences in physical activity and being less involved in playing online video games.

Cognitive Tests

Study patients were given a battery of cognitive tests, including the Montreal Cognitive Assessment; Symbol Digit Modalities Test (SDMT); Stroop test; and Brief Visuospatial Memory Test Revised (BVMT-R), immediate (10 and 30 seconds), and delayed recall (DR) (20 minutes).

All the cognitive tests were short and altogether took about 45 minutes to complete. In some cases, researchers used the Arabic version of these tests for the first time.

At baseline, the low vitamin D group scored lower on all cognitive tests except the Stroop test. The difference was significant for SDMT and BVMT-DR.

The low vitamin D group was given high doses of vitamin supplements (10,000 IU daily or 50,000 IU per week) for 3 months. The normal vitamin D group received usual care.

Patients kept a diary documenting sun exposure and vitamin D intake.

After 3 months, serum 25(OH)D levels in the low vitamin D group increased from a mean of 15.8 to 59.6 μg/mL (P < .0001). The normal vitamin D group also increased, but by much less. The difference between the normal and low vitamin D groups remained statistically significant.

After 3 months, performance on the BVMT-DR differed significantly. The test score was 9.4 for the normal vitamin D group compared with 7.8 for the low vitamin D group (P < .04).

At baseline, the difference in performance on the SDMT approached statistical significance (normal, 56.2 vs 50.4 for low; P = .07).

There was no significant between-group difference at either time point for any of the other cognitive tests.

Three months may not be long enough to show statistically significant differences in some test performances, according to Dr Darwish. Additional follow-up studies using more established and validated cognitive tests are needed, she said.

A multivariable analysis showed that, as expected, age was a predictor of cognitive performance for all cognitive tests at baseline and at 3 months. As well, more years of education predicted cognitive performance on the Stroop test and BVMT at baseline and the STMT at 3 months.

Performance Predictors

Vitamin D levels predicted better performance on the BVMT-DR after adjustment for disease duration, EDSS score, age, education, physical activity level, smoking status, alcohol intake, leisure activities, anxiety, and depression.

A higher anxiety score predicted a lower score on the SDMT. Cognitive performance and anxiety in MS seem to be affected by low vitamin D level and improve after vitamin D replacement, said the authors.

Interestingly, alcohol intake predicted a better cognitive score on the SDMT at baseline and at 3 months and the BMT-T1 at 3 months. This association needs further exploration, said Dr Darwish.

Although she didn't attend the presentation, Luanne Metz, MD, a neurologist and professor, clinical neurosciences, University of Calgary, Alberta, Canada, said the study's findings aren't surprising.

"One things that vitamin D does is increase a number of factors, including growth factors, and one of these is BDNF [brain-derived neurotrophic factor], which we know plays a role in cognition as well as inflammation."

At her own clinic, one of the first things patients with MS are told to do is start taking vitamin D supplements at a recommended dose of 4000 to 5000 IU a day. For Canadian patients with MS, "there's no point" in even getting serum vitamin D checked because almost all will have low levels, she said.

The study was funded by the AUB Medical Practice Plan and the Lebanese National Center Research. Dr Darwish has disclosed no relevant financial relationships.

Congress of the European Committee for Treatment and Research in MS (ECTRIMS) 2015. Parallel Session 2 129. Presented October 8, 2015.


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