Carpal tunnel syndrome (CTS) and vitamin D deficiency are two discrete common clinical pictures that can cause chronic pain. In this study, we aimed to evaluate the association of 25 (OH) D deficiency with electrophysiological findings and severity of pain in patients with mild CTS.

The consecutive patients admitted to our laboratory with the symptoms of CTS between May 2016 and August 2016 were enrolled in this study. According to their electrophysiological examination results, only the patients with normal conduction results and ones with mild grade CTS were included. Demographic data, the results of the electrophysiological studies, vitamin D levels (our laboratory normal is>20ng/mL), duration of pain and pain intensity due to CTS, which was assessed with visual analog scale, were collected.

Totally, 76 patients (36 patients with mild CTS and 40 without CTS) were included. In the mild CTS patients, vitamin D levels were significantly lower than those electrophysiologically normal patients (P=0.003). The relationship between gender, duration of pain and vitamin D levels were evaluated in the normal and mild CTS group. There was no significant relationship between the pain and vitamin D levels in the normal group, while vitamin D level was significantly lower in the mild CTS group (P=0.730 and P=0.002; respectively).

Vitamin D deficiency increases the pain intensity in patients with CTS. Treatment of vitamin D deficiency in these patients may play a role in pain relief. Further studies involving analyses of post-vitamin D replacement therapy are warranted to confirm the association between vitamin D deficiency and pain due to CTS.