Vitamin A level and related clinical factors in preterm infants

Objective To investigate the association between serum vitamin A levels and clinical factors in preterm infants. Methods A retrospective study was conducted on neonates admitted to Peking University Third Hospital from May 2013 to May 2014. Totally, 89 preterm neonates were recruited (preterm group). Fifty term babies with hyperbilirubinemia were selected as hyperbilirubinemia group and 50 healthy term babies were chosen as control group. High-performance liquid chromatography (HPLC) was used to examine the serum vitamin A concentrations for preterm babies at the age of 2, 7, 14 and 28 days, while those for babies in hyperbilirubinemia group was measured on one week old. Umbilical cord blood serum vitamin A concentrations were determined in control group. t-test, univariate analysis of variance or multiple linear regression was used for statistical analysis. Results (1) In the preterm group, the mean serum vitamin A levels at the age of 2, 7, 14 and 28 days were (0.136±0.060), (0.141±0.047), (0.122±0.053) and (0.134±0.073) mg/L, respectively, while (0.168±0.109) and (0.159±0.049) mg/L in hyperbilirubinemia and the control group. The proportions of vitamin A deficiency (lower than 0.20 mg/L) in preterm babies were 91.2% (62/68), 92.1% (58/63), 91.3% (42/46) and 84% (21/25) at the age of 2, 7, 14 and 28 days respectively. There was no significant difference in serum vitamin A levels between the age of 2 days and the rest in preterms (P>0.05). However, the vitamin A levels in preterm babies at the age of 2 and 7 days were lower than that of control and hyperbilirubinemia group, respectively (t=-2.068 and -1.790, both P 0.05). (3) Multiple factor analysis showed that respiratory distress syndrome, neonatal pneumonia, small for gestational age and maternal hypertensive diserders of pregnancy were associated with serum vitamin A level in early life of newborns (all P<0.05). Conclusion Preterm infants might require sufficient vitamin A supplementation due to low vitamin A level in their first month of life. Small for gestational age, maternal hypertensive disorders of pregnancy, respiratory distress syndrome and neonatal pneumonia are associated with serum vitamin A level in preterm infants. Key words: Vitamin A; Infant, premature