The effect of vitamin D on restless legs syndrome: prospective self-controlled case study

To evaluate the effect of vitamin D on severity of restless legs syndrome in patients with idiopathic restless legs syndrome (RLS).

Patients with idiopathic RLS completed questionnaires including the International Restless Legs Severity Scale (IRLSS) and were evaluated for vitamin D deficiency. Patients with deficiency of vitamin D were treated with 50,000 units per week for 2 months. At the end of the 2 months, vitamin D levels were re-measured and disease severity was re-evaluated in patients who reached adequate vitamin D level. Subgroups of IRLSS questionnaire were also analyzed.

Of 35 patients enrolled, 21 (60%) had vitamin D deficiency and received vitamin D therapy. In 2 patients, vitamin D levels did not rise to sufficient levels with supplementation and these 2 patients were excluded from analysis. The remaining 19 patients showed vitamin D levels increased from 13.2 ± 4.0 to 42.8 ± 9.6 ng/mL while IRLSS improved from 24.9 ± 5.1 to 21.1 ± 2.9 points (p <0.001). Selected subscores of the IRLSS were also improved including symptom severity (p <0.001), impact on sleep (p <0.001), symptom measures (p =0.002), and disease impact measures (p <0.001). There were trends toward improvement in subscores of frequency (p =0.11) and mood (p =0.051).

The findings suggest that vitamin D levels should be evaluated in patients with RLS and if vitamin D deficiency is revealed, consideration should be given to replacement therapy.u.