Serum Vitamin D Level And Rheumatoid Arthritis Disease Activity:Review And Meta-analysis

BackgroundThe evidence from epidemiological studies concerning the relationship between serum vitamin D concentrations and rheumatoid arthritis (RA) disease activity is inconsistent. This Meta-analysis is aimed at determining the magnitude of the correlation between RA and serum vitamin D.MethodsThrough multiple search strategies, relevant literature was identified and evaluated for quality before May 162015. Data extracted from eligible studies was synthesized to calculate pooled correlation coefficient (r), mean difference (MD) and odds ratio (OR).ResultsA total of 24 reports involving 3489 patients were selected for analysis. RA patients had lower serum vitamin D levels than healthy controls (MD:-16.52 nmol/L, 95% confidence intervals [CI]:-18.85 to-14.19 nmol/L). There existed a negative relationship between serum 25-hydroxyvitamin D (25OHD) level and disease activity index, e.g.25OHD vs. Disease Activity Score in 28 joints (DAS28):r=-0.13,95%CI-0.16 to-0.09; 25OHD vs. C-reactive protein:r=-0.12,95% CI-0.23 to-0.00. Additionally, latitude-stratified subgroup analysis yielded a relatively stronger negative correlation between 25OHD and DAS28 in low-latitude areas. This inverse relationship also appeared more significant in developing countries than in developed countries. No publication bias was detected.ConclusionRA patients had lower serum vitamin D values than healthy controls. There was a negative association between serum vitamin D and RA disease activity. However, more strictly controlled studies are needed to validate these findings.