Vitamin D deficiency may be linked to restless legs syndrome

A new study from Turkey reports that people with low blood vitamin D concentrations may have an increased risk of developing involuntary movements of the legs.

The observational study measured the vitamin D levels in blood samples of 155 patients, between 18 to
65 years of age, with musculoskeletal symptoms and an unpleasant feeling in the lower extremities (1). The study results showed that among the 119 patients who were vitamin D deficient (below 20 ng/ml) about 50% were diagnosed with restless legs syndrome (RLS), compared to only 6.7% of patients identified to have RLS among the 36 participants with normal vitamin D levels (above 20 ng/ml). In addition to the higher presence of RLS in the vitamin D deficiency group, the patients in this group reported more severe symptoms.

The researchers commented that these findings demonstrate a possible association between low levels of vitamin D, involved in the regulation of the nervous system, and the development of RLS, characterized by a dysfunction of the dopamine (neurotransmitter) system effecting the activity of neurons regulating i. a. mo- vements. Intervention studies investigating the effects of vitamin D treatment of RLS patients are needed to confirm this relationship. Vitamin D deficiency should be considered in RLS patients, particularly those who have the diagnosis RLS without known cause (e.g., no related comorbidities).

RLS is a distressing sleep disorder that affects 4 to 29% of adults in the Western industrialized world (2). The major characteristic of this disease is a compelling urge to move the legs, with an unpleasant feeling in the lower extremities. It typically starts or becomes worse during rest periods and deteriorates during the eve- ning and at night; the symptoms partially or totally disappear with movement. The successful results of dopamine agonist use in RLS treatment supports the do- paminergic dysfunction hypothesis in RLS (3).

1. Oran M. et al. Possible association between vitamin D deficiency and restless legs syndrome. Neuropsychiatric Disease and Treatment. 2014; 10:953–958.
   
2. Innes K. E. et al. Prevalence of restless legs syndrome in North American and Western European populations: a systematic review. Sleep Med. 2011; 12(7):623–634.
   
3. Zintzaras E. et al. Randomized trials of dopamine agonists in restless legs syndrome: a systematic review, quality assessment, and meta-analysis. Clin Ther. 2010; 32(2):221–237.