Vitamin D deficiency and its supplementation in patients with amyotrophic lateral sclerosis.

We studied 25-hydroxyvitamin D (vitamin D) levels in patients with amyotrophic lateral sclerosis (ALS) and the effect of vitamin D supplementation. Vitamin D levels were checked in 37 consecutive patients with ALS. Demographic data, vitamin D supplementation, change in Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) score, and side effects from vitamin D were noted over a 9 month follow-up period. ALSFRS-R scores were compared between patients who took vitamin D and those who did not. The median age was 55 years and median time since symptom onset was 61 months. The mean vitamin D level was 22.3 ng/mL (normal range, 30-80 ng/mL). Eighty-one percent of patients had a vitamin D level lower than 30 ng/mL and 43% had a vitamin D level lower than 20 ng/mL. Twenty patients took 2000 international units of vitamin D daily. After adjustment for age and baseline vitamin D levels in a linear regression model, the ALSFRS-R score decline was smaller in patients taking vitamin D at 9 months (p=0.02) but was not significantly different at 3 or 6 months. Median vitamin D levels rose from 18.5 to 31.0 ng/mL at 6 months in the group taking vitamin D. No side effects secondary to vitamin D supplementation were reported. Vitamin D supplementation at 2000 international units daily was safe over a period of 9 months and may have a beneficial effect on ALSFRS-R scores. Further studies are warranted to determine whether there is a benefit in vitamin D supplementation for all ALS patients.