Study On Relationship Between Serum 25-Hydroxyvitamin D3 And Systemic Lupus Erythematosus

Objectives To investigate the level of serum 25-hydroxyvitamin D3[25(OH)D3] in patients with SLE, and to assess the association between 25(OH)D3 and clinical manifestations, laboratory data and disease severity, and explore the role of vitamin D in SLE.Methods1.121 SLE patients admitted to the department of Rheumatology of the First Affiliated Hospital of Zhengzhou University from June to September of 2015 were enrolled in our study. Healthy controls consisted of the 150 healthy volunteers from the Physical Examination Center. Demographic characteristics, laboratory data and blood samples were collected.2.The level of serum 25(OH)D3 was measured by electrochemiluminescence immunoassay(ECLI). All the patients were divided into groups according to organ damage, autoantibodies, disease severity. Then, the difference of serum 25(OH)D3concentrations in different groups and the association between 25(OH)D3 levels and disease severity were analysed.3.All statistical analyses were performed using the statistical software SPSS19.0. Quantitative data were expressed using mean±standard deviation(x±s), and qualitative data were expressed using percentage(%). Comparisons of the level of serum 25OHD3 between two groups were done using the two-tailed Student’s t-test.Single factor variance analysis or nonparametric test(Mann-Whitney U test) were used to compare quantitative data in multi groups. Correlations between 25(OH)D3level and clinical characteristics, autoantibodies were done using c 2 test, and Spearman rank correlation analysis were used to evaluate the association between laboratory data and serum 25OHD3 level. The association between a greater severity of disease and predictors was assessed by fitting inary logistic regression univariate and multivariate models. P-value <0.05 were considered statistically significant.Results1. The level of serum 25(OH)D3 in SLE group and control group: The mean level of 25(OH)D3 in SLE group was significantly lower than control group[(13.48±7.76)ng/ml vs(22.44±7.45)ng/ml, P<0.001], while cases of 25(OH)D3insufficiency/deficiency in SLE group were more than control group(P<0.001).2. The level of serum 25(OH)D3 and clinical characteristics in SLE patients:Positive relationship between the level of 25(OH)D3 and the level of white blood cell count, hemoglobin, lymphocyte count, plasma albumin, globulin, complement C3,immunoglobulin Ig G(all P<0.05). Negative correlation between the level of 24 hours urinary protein quantity, total cholesterol, triglycerideand and 25(OH)D3(all P<0.05).No correlation was found between the level of platelet count, blood sugar,complement C4, erythrocyte sedimentation rate, C reactive protein, immunoglobulin Ig M, immunoglobulin Ig A and 25(OH)D3(all P>0.05).3. The level of serum 25(OH)D3 and autoantibodies in SLE patients: No significant difference in serum 25(OH)D3 concentrations was found between SLE patients with positive antinuclear antibodies, anti-double-stranded DNA, anti-Sm,anti-SSA52, anti-SSA60, anti-Aun A, anti-His, anti-ribosomal P, anti-RNP antibodies,anticardiolipin antibodies or not, respectively(both P>0.05). Significant difference in serum 25(OH)D3 concentrations between SLE patients with anti-SSB or not was found(P<0.05).4. The level of serum 25(OH)D3 and organ damage in SLE patients: There was no difference in 25(OH)D3 serum levels between SLE patients with facial erythema,photosensitivity, dental ulcer, alopecia, arthritis and vasculitis or not(all P>0.05);25(OH)D3 level was influenced by kidney damage, serositis and hematological system(all P<0.05).5. The level of serum 25(OH)D3 and the therapy of SLE patients: No significant difference was found between patients incipient, use of glucocorticoid,hydroxychloroquine, immunosuppressive drugs or not in 25(OH)D3 serum concentrations(all P>0.05). And there was a negative correlation between 25(OH)D3levels and daily average of glucocorticoid(>10mg/d or not) in a month.6. The level of serum 25(OH)D3 and disease severity in SLE patients:1) The mean level of serum 25(OH)D3 was significantly lower in active group than in inactive group [(10.15±7.49)ng/ml vs(15.52±7.25)ng/ml, t=3.902, P<0.001].Pearson correlation analysis indicated a negative correlation between 25(OH)D3levels and SLEDAI(r=-0.413, P<0.001). Logistic regression analysis revealed that the cut-off point of 25(OH)D3 concentration was 10 ng/ml where its level was correlated with increased SLEDAI(OR 6.42, 95%CI 1.726~23.888, P=0.006).2) There was no difference in 25(OH)D3 levels [(12.57±7.22)ng/ml vs(14.87±8.41)ng/ml, t=1.6, P=0.112]between group without organ damage and group with moderate to severe organ damage.Conclusions Vitamin D deficiency is highly prevalent in patients with SLE, which might participate in the pathogenesis of lupus nephritis. There was a negative relationship between serum 25(OH)D3 and SLEDAI, severe deficiency increased the risk for moderate to severe disease activity.