The Relationship Between 25 (OH) Vitamin D Level and the Severity of Disease and Sleep Quality in Restless Legs Syndrome

Abstract

Objective: Restless legs syndrome (RLS) is a common chronic sensory-motor neurologic disease with serious disabling effects on affected individuals’ physical and emotional health and quality of life. The underlying pathophysiology of the disease is not clear but iron metabolism disorders and dopaminergic dysfunction along with a genetic predisposition are blamed, and recently vitamin D deficiency was considered to play an important role in RLS. In this study, we aimed to investigate the relationship of concentrations of a vitamin D metabolite, 25 (OH) vitamin D, with RLS severity and quality of sleep.

Materials and Methods: We enrolled 152 patients aged between 18 and 75 years who were referred to our general neurology outpatient clinic in Istanbul Training and Research Hospital, and diagnosed with RLS according to the International Restless Legs Syndrome Study Group diagnostic criteria, between September 2016 and September 2018. The patients were classified as the vitamin D deficiency group (<20 ng/mL, group 1) and normal vitamin D group (>20 ng/mL, group 2). Both groups were evaluated for their RLS severity index and Pittsburgh Sleep Quality Index (PQI). Both groups are compared statistically.

Results: Of the 152 patients, 89 patients had low vitamin D concentrations (<20 ng/mL) (group 1) and 63 had normal vitamin D concentrations (>20 ng/mL) (group 2). There was no significant difference in terms of age, sex, body mass index, and cigarette consumption (p>0.05). There were significant differences between the two groups in terms of upper extremity involvement, ferritin concentrations, PQI, and RLS severity scores (p<0.05).

Conclusion: The present study demonstrated that patients who are vitamin D deficient might have more severe RLS symptoms and an impaired quality of sleep compared with other patients with RLS.