Efficacy of vitamin D replacement therapy in restless legs syndrome: a randomized control trial

Purpose Restless legs syndrome is a movement sleep disorder that may be linked to dopaminergic dysfunction and in which vitamin D may play a role. This 12-week randomized, placebo-controlled trial elucidated the efficacy of vitamin D supplements in decreasing restless legs syndrome symptom severity. Methods Thirty-five subjects with restless legs syndrome, diagnosed using the International Restless Legs Syndrome Study Group criteria, were enrolled. The subjects were randomized to orally receive either vitamin D (50,000 IU caplets) or a placebo. All medications were administered weekly using a direct observation technique. Clinical assessments, including those for restless legs syndrome severity, were conducted at baseline and the end of the study using the International Restless Legs Syndrome Study Group rating scale. The serum vitamin D levels and bone profiles were measured at baseline and every 4 weeks. The primary endpoint was the change in the restless legs syndrome severity score from baseline to week 12. There were 17 and 18 patients in the vitamin D and placebo groups, respectively. Results The groups did not differ with respect to age, sex, restless legs syndrome severity, or vitamin D levels. Participants in the vitamin D group showed no significant change in the mean restless legs syndrome severity score compared with the placebo group. Conclusions The results suggest that vitamin D supplementation does not improve restless legs syndrome symptoms. Clinical trial registration number ClinicalTrials.gov : NCT02256215 (available from: https://clinicaltrials.gov/ct2/show/NCT02256215 ).