Serum 25(OH)D Level And Determinants In IgA Phropathy Patients

Objective:This study aimed to understand the serum 25(OH)D level and investigate vitamin D level determinants in IgA nephropathy(IgAN)patients.Methods:We performed a cross-sectional study to measure the level of 25(OH)D in IgAN patients who were first-time onset.A self-designed questionnaire was used to conduct a lifestyle survey of patients,and the general information,laboratories data and renal pathological data of patients were collected.Patients were divided into vitamin D deficient and non-deficient groups depending on the 25(OH)D concentration.Clinical,biochemical and renal pathological parameters were evaluated for associated factors of vitamin D deficiency by logistic regression.Result:1.Serum 25(OH)D level of IgAN patients:A total of 130 IgAN patients completed all evaluations and were included in the statistical analysis.The mean serum 25(OH)D level of patients was 49.19±23.50 nmol/L,and the insufficient and deficiency ratio were 56.2%and 32.3%respectively;compared with 60 healthy subjects matched with age and gender,The IgAN patients had a lower 25(OH)D staturs and higher proportion of 25(OH)D deficiency(P<0.01).46.2%of IgAN patients were sampled during the winter/spring(December-May),and 53.8%of IgAN patients were sampled during the summer/autumn(June-November);Compared with the summer/autumn group,the winter/spring group had a lower 25(OH)D status(t=-2.613,P<0.05),and The proportion of 25(OH)D deficiency in the winter/spring group was higher(?2=6.194,P<0.05).2.Univariate analysis of 25(OH)D levels in IgAN patients:Among 130 IgAN patients,46.9%had a degree of education greater than 12 years;83.1%lived in urban areas,85.4%were work indoors,they exercised no more than three times a week,and 57.7%(75/130)almost had no exercise,58.5%(75/130)exposured to sunlight for no more than 30 minutes per day,60%to 70%of patients rarely eat foods rich in vitamin D,such as eggs,mushrooms,animal liver and fish.There were no significant differences in the education,Place of residence,workplace,Physical activity,sun exposure and vitamin D diet beteewn the deficiency group and non-deficient group(P>0.05).The level of 24h urine protein,PTH,P,TC,HDL-C,LDL-C were higher in the deficiency group(P<0.05).In addition,the deficiency group had a lower level of Ca,Serum albumin(P<0.05).the tubular atrophy/renal interstitial fibrosis lesions of the deficiency group were heavier than the non-deficient groups.(Z=-2.000,P<0.05).3.Multivariate analysis of factors affecting 25(OH)D levels in IgAN patients:The variables with P value<0.2 in the univariate analysis were included in the multivariate logistic regression model,and the stepwise regression method was used to screen the suspected related factors:education(OR=5.087;95%Cl 1.671-15.428;P=0.004),24h urine protein(OR=2.195;95%Cl 1.371-3.512);P=0.001),Serum albumin(OR=3.883;95%Cl 1.633-9.231;P=0.002)were independent risk factors for 25(OH)D deficiency in IgAN patients.Conelutions:The insufficient and deficiency of 25(OH)D in IgAN patients is very common and is significantly lower than that healthy people.Vitamin D deficiency is more serious in winter and spring.High degree of education,large amount of urinary protein,and hypoalbuminemia are independent risk factors for serum 25(OH)D deficiency in IgAN patients.