Role of Vitamin D in rheumatoid arthritis and its association with neuropathic pain: a systematic review and meta-analysis

Abstract

• Background: Rheumatoid arthritis (RA) is the most common autoimmune disease found in about 1% of adults worldwide. The cause of RA is unknown but there is a combination of genetic and multiple environmental factors dietary resulting in systemic inflammation. Vitamin D not only plays a major role in the regulation of bone mineral homeostasis but also plays a role in in the regulation of the immune response through a different mechanism, these data support a vitamin D deficiency role in the development and progression of RA and other autoimmune diseases. Long-term vitamin D deficiency may lead to decreased immune response and chronic inflammation, which may cause disabling pain. Individuals with vitamin D deficiency often report increased pain perception, which has been referred to hyperinnervation and hypersensitivity in nerve fibers. • Methods: We searched the PUBMED, EMBASE, and Cochrane databases and performed a meta-analysis examining the vitamin D level and prevalence of vitamin D deficiency in patients with RA compared to healthy controls and the relation between the vitamin D level and disease activity score 28 (DAS28) in RA patients, also we used (LANSS) to evaluate NP in patients with RA. • Results Systematic review of 8 articles found that the serum vitamin D level in the RA group was significantly lower than that in the control group. In addition, vitamin D deficiency was more observed in RA patients with neuropathic pain. • Conclusion This systematic review and meta-analysis suggest that vitamin D plays a key role in the susceptibility and activity of RA. Further studies are necessary to elucidate that vitamin D status directly contributes to the pathogenesis of RA and to study the effect of vitamin D supplement in RA patients with neuropathic pain.