Vitamin D supplementation has no effects on progression of motor dysfunction in amyotrophic lateral sclerosis (ALS)

To investigate the effects of cholecalciferol supplementation on the progression of motor disability in a cohort of amyotrophic lateral sclerosis (ALS) patients with low blood 25-hydroxyvitamin D3 [25(OH)D] levels, on the basis of the hypothesis of potential neuroprotective effects of vitamin D supplementation.

Forty-eight ALS patients, 34 with deficient (<20 ng/mL) and 14 with insufficient (20-29 ng/mL) serum levels of 25(OH)D, were randomized and treated by 3 different doses of cholecalciferol [50.000, 75.000 and 100.000 international units (IU) /month] and evaluated after 6-months. Assessment of motor dysfunction at baseline and after 6 months included ALS Functional Rating Scale-Revised (ALFRS-R) and upper motor neuron (UMN) scores and blood samples for 25(OH)D levels.

Clinical data of 33 patients were available after 6 months. Analysis of Covariance (ANCOVA), with pre-treatment measurements included as covariate, did not show statistically significant differences in the ALSFRS-R (p > 0.05) and UMN (p > 0.05) among the patient groups who underwent 3 different doses of cholecalciferol. Conversely, the treatment with 75.000 IU/month or 100.000 IU/month induced a significant increase in serum levels of 25(OH)D in comparison with the supplementation with 50.000 IU/month; no significant differences were found between 75.000 IU/month and 100.000 IU/month.

Our findings highlighted that 6-month supplementation of vitamin D in ALS patients had no significant effects on motor dysfunction. However, it is recommended to prevent medical complications of vitamin D deficiency in ALS patients as well as in other populations of neurodegenerative patients, characterized by low mobility and decreased sun exposure.