Vitamin D Level And Related Factors Analysis In Preterm Infants From Puyang City:a Single Center Retrospective Study

BackgroundVitamin D is an essential nutrient for the body.Premature infants are one of High-risk groups for vitamin D deficiency,and preterm birth and the development of neonatal diseases associated with vitamin D deficiency.There are significant differences in the basic vitamin D levels of humans in different regions.At present,the relevant research focuses on larger cities,and the epidemiological data on vitamin D in small towns are relatively insufficient.Therefore,the purpose of this study was to investigate the vitamin D nutritional status of premature infants in our center and analyze the related risk factors,so as to provide a basis for improving the vitamin D deficiency of premature infants and supplementing vitamin D after birth for public health in the region.ObjectiveVitamin D nutritional status will be anslyzed based on basic data from premature infants and their mothers hospitalized in Puyang People ’s Hospital,and to explore possible influencing factors on premature infants with vitamin D deficiency.The aim of our work is to provide helpful advice and prevention strategies for vitamin D deficiency in premature infants in local public health.MethodsPremature infants who were transferred to the neonatal intensive care unit after birth were recruited in Puyang People ’s Hospital from January 2020 to December 2021.The cases suffered with liver and kidney diseases,thyroid dysfunction,and no vitamin D record were excluded.Premature infants were also excluded while mothers had liver and kidney diseases,abnormal thyroid hormone,cholestasis or history of drugs affecting vitamin D levels.We identified gestational age,weight,gender,seasons of birth,the numbers of birth,maternal age,pregnancy complications,occupation,living environment,the supplemental dose of vitamin D in pregnancy as survey indicators.Venous blood samples were collected from all cases within 24 hours after birth.One-step competitive immunoassay was used to detect the level of 25(OH)D.The nutritional status and grading of vitamin D were assessed according to Practice Guideline for Clinical Issues Related to Vitamin D Nutrition in Chinese Children(version 2022).The premature infants were divided into small for gestational age group,appropriate for gestational age group and large for gestational age group according to gestational age and weight.According to the gestational age at birth,they were divided into extremely preterm group,very early preterm group,moderate preterm group and late preterm group.The changes of vitamin D levels and related influencing factors in different groups of premature infants were analyzed and summarized.Results263 premature infants were recruited in this study according to the Inclusion and exclusion criteria,including 48 cases(18.3%)of vitamin D deficiency,117 cases(44.5%)of insufficiency,and 98 cases(37.2%)of sufficiency.There were 179 premature infants those born by the mothers who supplement vitamin D at a dose of ≥ 500IU/d from the mid-pregnancy(weeks of gestation 14 0/7 to 27 6/7 weeks),including 43 cases(24.0%)of vitamin D deficiency,85 cases(47.5%)of insufficiency.The vitamin D level of premature infants was not affected by different gestational age groups,singleton/multiple births,different birth weight groups,gender,maternal age,maternal pregnancy complications,living environment and working environment,and the differences were not statistically significant(P > 0.05).The serum vitamin D level between the premature infants born by the mothers who supplement vitamin D at a dose of ≥500IU/d from the mid-pregnancy and those born by the mothers who supplement vitamin D at a dose of<500IU/d was statistically significant(Z:2.304,P<0.05);The overall distribution of vitamin D in serum from the premature infants of the season groups(spring,summer,autumn and winter)was statistically different(H:39.021,P<0.05);The result of the Logistic regression analysis showed that the supplemental dose of vitamin D in pregnancy and the birth season were risk factors affecting the vitamin D level in serum from the premature infants[Exp(B)=0.191,95%CI 0.101-0.363,P < 0.05],[Exp(B)=0.245,95%CI 0.141-0.426,P<0.05].Conclusions1.The incidence of vitamin D deficiency in premature infants is high,which is affected by factors of delivery in winter.2.Maternal vitamin D supplementation during pregnancy greater than 500 IU / d can improve the vitamin D level of preterm infants at birth,but it is not enough to prevent neonatal vitamin D deficiency efficiently.