RESUMO
Objective To explore the relationship between serum 25-hydroxy vitamin D [25(OH)D] concentrations and the risk of Henoch-Schonlein purpura (HSP).Methods A case control study was designed.Serum 25 (OH)D concentrations were measured by radioimmunoassay in 214 participants,including 53 H SP patients and 161 status-matched healthy controls.Information concerning demographic data,genetic,background,and environmental exposures was collected using questionnaire.The study participants were divided into four groups according to quartile range of 25(OH)D concentration and logistic regression modeling was used to evaluate the relation with HSP risk by estimating odds ratios(OR)and 95％confidence intervals(CI).Results The HSP group had a significantly lower concentration of 25(OH)D than the control group (the median in the HSP group was 11.4 ng/mL;controls:15.36 ng/mL,P＜0.05).When the first interval was set as the reference level,the OR (95 ％ CI) of the second,third,and fourth intervals were:0.468(0.341-0.771),0.442(0.302-0.627),0.339 (0.199-0.501).After adjusting the analysis for the presence of pathogenic related confounding fact OR,the OR(95％CI)of the second,third,and fourth intervals were:0.459(0.333-0.741),0.408(0.317-0.611),0.387 (0.221-0.517).The 25 (OH) D level was inversely correlated with the risk of HSP(P＜ 0.05).Conclusion The risk of HSP was decreased with the increase of serum 25 (OH) D concentration,25 (OH) D may be a protection factor in the pathogenesis of HSP.