Changes and clinical significance of serum 25-hydroxy-vitamin D levels in rheumatoid arthritis / 中华风湿病学杂志

ABSTRACT

Objective To determine the serum level of 25-hydroxyvitamin D[25(OH)D] in rheumatoid arthritis (RA) patients and to assess the association of 25(OH)D with clinical presentations.Methods Serum 25(OH)D levels were detected by enzyme-linked immunosorbent assay (ELISA) in 130 cases with RA and 80 healthy controls.The detailed clinical data of the RA patients were recorded and bone mineral density (BMD) were measured by dual-energy X-ray absor-ptiometry (DXA).Sharp score of both hands were measured for evaluating the effects of 25(OH)D on bone erosion.T-test and one-way ANOVA test were used for data analysis,and x2 test was used to compare the differences between groups.Pearson's test was adsopted for correlation analysis.Muhi-variate analysis and Logistic analysis were carried out for risk factors identification.Results ① The serum levels of 25 (OH)D were markedly lower in the RA group than the control group [(17±6) ng/ml vs (23±6) ng/ml,t=-6.624,P＜0.01],while cases of 25(OH)D insufficiency/deficiency in the RA group were more than the control group (98.5％ vs 81.5％,x2=26.291,P＜0.01); ② Negative correlation was detected between 25(OH) D levels and the followingduration of morning stiffness,tender joint count (TJC),swollen joint count (SJC),erythrocyte sedimentation rate (ESR),C-reactive protein (CRP),health assessment questionnaire (HAQ) of the patients with RA (r=-0370,-0.307,-0.243,-0.369,-0.175,-0.381,both P＜0.05),respectively; ③ 25 (OH)D levels were signific-antly lower in group with moderate and severe disease activity than in group with stable or low disease activity (both P＜0.05); Insufficiency/deficiency of 25 (OH)D was the risk factor for disease activity by multiple regression analysis (b=-0.46,P=0.029); ④ No statistically significant association was detected between 25(OH)D and degree of bone erosion in RA (P＞0.05); ⑤ BMD was classified into three groupsnormal,osteopenia and osteoporosis,and significant differences of serum 25(OH)D levels were found by compared with each group (P＜0.01).Normal serum 25 (OH)D level was a protective factor for RA-induced osteoporosis by Logistic rcgression analysis (OR=0.898,95％CI 0.830-0.972,P=0.008).Conclusion Significantly low 25 (OH)D level could be found in patients with RA.Negative correlation is detected between 25 (OH)D level and disease activity and osteoporosis respectively in patients with RA.Insufficiency/deficiency of 25 (OH)D is the risk factor for disease activity and RA-induced osteoporosis.