Relationship between serum vitamin D level and nosocomial infection in preterm infants

Abstract

Objective To investigate the relationship between serum vitamin D level at birth and nosocomial infection in preterm infants. Methods A total of 246 preterm infants with gestational age less than 32 weeks at birth who were hospitalized in the Neonatal Intensive Care Unit (NICU) of The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University from January 1, 2011 to December 31, 2015 were enrolled as research subjects. These preterm infants were divided into nosocomial infection group (n=63) and control group (n=183) according to whether they had nosocomial infection or not. These preterm infants in nosocomial infection group were further divided into sepsis subgroup (n=27) and other infections subgroup (n=36) according to their infection types. Serum 25-hydroxyvitamin D [25(OH)VitD] levels at birth of all preterm infants were detected by chemiluminescence immunoassay. The level of serum 25(OH)VitD and the incidence of vitamin D deficiency at birth were compared between nosocomial infection group and control group, different subgroups and control group by Wilcoxon rank sum test and chi-square test, respectively. This study was reviewed by the Ethics Committee of The Affiliated Wuxi Maternity and Child Health Care Hospital of Nanjing Medical University (Approval Number: 2013-01-1015-01). Results ①There were no significantly differences between nosocomial infection group and control group among gestational age, birth weight, gender, birth season of preterm infants, constituent ratio of delivery mode, maternal age, body mass index (BMI) in the first trimester of pregnancy, and incidences of gestational diabetes mellitus, pregnancy hypertension, chorionic amniocentesis of pregnant mother (P>0.05). ②The incidence of vitamin D deficiency at birth and nosocomial infection of preterm infants were 45.5% (112/246) and 25.6% (63/246), respectively. There were no significantly differences between nosocomial infection group and control group in serum 25(OH)VitD level and incidence of vitamin D deficiency at birth (P>0.05). ③The level of serum 25(OH)VitD at birth in sepsis subgroup was 28.1 nmol/L (23.5-34.1 nmol/L), which was significantly lower than that 32.7 nmol/L (25.3-45.4 nmol/L) in control group, and the difference was statistically significant (Z=-2.011, P=0.044). The incidence of vitamin D deficiency at birth was 70.4% (19/27) in sepsis subgroup, which was significantly higher than that 43.2% (79/183) in control group, and the difference also was statistically significant (χ2=6.995, P=0.008). There were no significant differences in serum 25(OH)VitD level and incidence of vitamin D deficiency at birth between other infections subgroup and control group (P>0.05). Conclusions There may be no association between serum 25(OH)VitD level at birth and incidence of nosocomial infection in preterm infants. Vitamin D deficiency may increase the incidence of nosocomial infection sepsis. The relationship between serum 25(OH)VitD level at birth and nosocomial infection need to be further confirmed by large sample, multicenter, randomized and controlled studies. Key words: Intensive care, neonatal; Vitamin D; Calcifediol; Vitamin D deficiency; Cross infection; Sepsis; Infant, premature