Background Vitamin D deficiency contributes to rheumatoid arthritis (RA) activity. It regulates the immune response through various pathways. Augmented pain perception in vitamin D deficiency is linked to increased sensitivity of the nerves. Aim Assessment of vitamin D levels in RA patients and their correlation with disease activity, as well as any potential association between vitamin D and neuropathic pain (NP). Patients and methods The study included 40 RA patients and 40 matched apparently healthy controls without NP. Patients were divided into two groups: group I: ( n =20), RA patients with NP (LANSS≥12), group II: ( n =20), RA patients without NP (LANSS<12). Vitamin D levels were measured in RA patients and controls. RA patients with NP and controls were evaluated by nerve conduction study. Disease activity score 28 (DAS28) was assessed. Results RA patients had significantly lower vitamin D than controls (16.68 ± 7.37 ng/ml and 24.4 ± 6.02 ng/ml vs. 29.86 ± 4.09 ng/ml; P <0.001). Serum vitamin D was correlated inversely with LANSS, DAS28, and modified health assessment questionnaire in RA patients. Carpal tunnel syndrome was detected in (65%), peripheral polyneuropathy in (50%), and mononeuritis multiplex in (10%) of RA patients with NP. Conclusion Vitamin D deficiency is more prevalent in RA, associated with high DAS28, and could be a cause of NP.
Abozeid et al. (Wed,) studied this question.