The Relationship Between 25 Hydroxyvitamin D Levels In Premature Infants And Lung Disease

Objective: To assess preterm infants(gestational age < 35 weeks)after born25-hydroxyitamin D(25 hydroxylvitamin D,25(OH)D)level,analysis the influence factors of low levels of 25(OH)D,compare the differences of different 25(OH)D levels between premature infants with pulmonary diseases,other clinical diseases and clinical respiratory treatment,explore its relationship with pulmonary diseases and other clinical diseases.Methods: From October 2018 to October 2019,premature infants(gestational age< 35 weeks)were enrolled in the Neonatal department of Dalian Women and Children’s Medical Center.Routine hepatitis virus + syphilis + HIV testing was performed within24 hours after birth,and the remaining blood samples were used for 25(OH)D testing,according to the concentration of 25(OH)D,all subjects were divided into Vitamin D(VD)deficiency group(25(OH)D < 20ng/ml)and non-VD deficiency group(25(OH)D≥20ng/ml).Data were collected as following,premature infants(gestational age,birth weight,sex,single/twin,IVF,umbilical cord blood calcium,season of birth,Apgar score(1,5 minutes)),maternal information(maternal age,cesarean section/vaginal delivery,premature rupture of fetal membranes,gestational diabetes,gestational hypertension,prenatal glucocorticoid),clinical disease including neonatal respiratory distress syndrome,bronchopulmonary dysplasia(Bronchopulmonary dysplasia,BPD),wet lung,neonatal pneumonia,pulmonary hemorrhage,pneumothorax,asphyxia,sepsis,necrotizing enterocolitis,anemia,intracranial hemorrhage,hypoglycemia;clinical respiratory therapy including hospital stay,whether mechanical ventilation and durationof mechanical ventilation,whether continuous positive airway pressure(Continuous Positive Airway Pressure,CPAP)and duration of CPAP,oxygen and the time of oxygen inhaling.To compare the differences between the two groups in preterm and maternal data,incidence of pulmonary diseases and other clinical diseases,and clinical respiratory treatment;the influence factors of VD deficiency and its correlation with pulmonary diseases and other clinical diseases were investigated by multivariate analysis in the VD deficiency group.Results: A total of 169 premature infants(gestational age < 35 weeks)were included.Those who did not meet the experimental standards were excluded,and 158 were finally included.The average gestational age was 32.4±2.0 weeks,and the average concentration of 25(OH)D was 17.2±7.4ng/ml.105 patients(66.5%)with postnatal25(OH)D<20ng/ml were included in the VD deficiency group.53 patients(33.5%)with postnatal 25(OH)D≥20ng/ml were included in the non-VD deficiency group.Analysis of data on premature infants showed that the proportion of IVF in the non-VD deficiency group(73.6%)was higher than that in the VD deficiency group(44.8%),and there was a statistical difference between the two groups(P = 0.001).Season of birth was related to 25(OH)D level(P = 0.024).There were no differences in gestational age,birth weight,gender,twins,umbilical cord blood calcium,and Apgar score(1,5minutes)between groups(P > 0.05).Among maternal factors,maternal age of VD deficiency group(29.0±4.8 years)was significantly lower than that of non-VD deficiency group(33.6±3.8 years),and the difference was statistically significant(P =0.000).There was no significant difference between the two groups in delivery mode,gestational diseases(premature rupture of membranes,gestational diabetes,gestational hypertension)and prenatal glucocorticoids(P > 0.05).In clinical diseases,the incidence of BPD in VD deficiency group(14.3%)was significantly higher than that in non-VD deficiency group(1.9%),(P = 0.015);among other complications(neonatal respiratory distress syndrome,neonatal pneumonia,pneumothorax,pulmonary hemorrhage,asphyxia,neonatal sepsis,necrotizing enterocolitis,anemia,intracranial hemorrhage,hypoglycemia)showed no statistical difference between the two groups(P > 0.05).Interms of clinical respiratory treatment,there were no statistically significant differences between the two groups in hospital stays,utilization rate and duration of mechanical ventilation,utilization rate and duration of CPAP,oxygen inhalation rate and duration of inhalation(P > 0.05).The results of multivariate analysis showed that IVF was a protective factor for VD deficiency(OR = 0.408,95%CI 0.178～0.933).Advanced maternal age was a protective factor for VD deficiency(OR = 0.819,95%CI0.740～0.906).Spring birth(as compared to winter)was a risk factor for VD deficiency(OR = 4.117,95%CI 1.427～11.881).VD deficiency is a risk factor for BPD(OR =11.437,95%CI 1.345～97.230).Conclusion: In this study,VD deficiency(25(OH)D < 20ng/ml)existed in 66.5%of preterm infants(gestational age < 35 weeks)after birth.Preterm infants born in spring(compared with winter),low age of mothers,and natural conception(compared with IVF)are more likely to be in VD deficiency group.Premature infants with VD deficiency are more likely to develop BPD.There was no correlation between 25(OH)D level and cord blood calcium.In this study,the effect of VD deficiency on long-term respiratory outcomes of premature infants was not investigated in depth,and further study is needed.