Vitamin D status and neuromyelitis optica spectrum disease: A systematic review and meta-analysis

Abstract

Background and objective: There's an increasing body of evidence on vitamin D deficiency and the risk of neuromyelitis optica spectrum disorder (NMOSD). The aim of this meta-analysis was to assess serum vitamin D levels in patients with NMOSD versus healthy controls.

Methods: We searched PubMed, EMBASE, Cochrane Library, Web of Science and CNKI for publications up to November 2022 and explored the relationship between NMOSD and serum vitamin D levels. The standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated using a random-effects model. Subgroup analysis and sensitivity analysis were applied to explore the sources of heterogeneity. Begg's test, Egger's test, and Egger's funnel plot were adopted to evaluate publication bias.

Results: 6 studies (including 319 patients and 595 healthy controls) met the inclusion criteria and all compared vitamin D levels in patients with NMOSD versus healthy controls. Levels of serum vitamin D detected in NMOSD patients were significantly lower than those in healthy controls (SMD=-1.57, 95% CI=-2.27 ∼ -0.87, P<0.001, I² = 94.6%). The results of the different sensitivity analysis remained statistically significant, which demonstrated the robustness of the meta-analysis. There was no significant publication bias in our meta-analysis (P>0.05).

Conclusion: Patients with NMOSD showed significantly reduced vitamin D levels compared with healthy controls. Our findings highlighted the importance of measuring vitamin D levels in patients with NMOSD. Multi-center randomized controlled trials with large samples will further confirm whether the association is casual and modifiable.

Keywords: Meta-analysis; Neuromyelitis optica spectrum disease; Sensitivity analysis; Systematic review; Vitamin D.