Associations between intake of vitamins E and A and serum concentrations in preterm infants: A retrospective cohort study.

BACKGROUND: Infants in neonatal intensive care are at risk of both deficiency and excess of fat-soluble vitamins, particularly E and A, due to limited reserves and the need for prolonged intravenous nutrition. We aimed to determine the effects of increased intravenous vitamin intake and to characterise the relationships between vitamin intake and serum concentrations. METHODS: Retrospective cohort of infants admitted to neonatal intensive care who had serum vitamin E or A concentrations quantified in the hospital laboratory using high-performance liquid chromatography. Associations between vitamin intakes, serum concentrations, neonatal outcomes, and maternal ethnicity were explored. RESULTS: Longer duration of intravenous nutrition was associated with higher serum concentrations of vitamin E (Spearman's ρ = 0.45, p < 0.001), but not vitamin A (ρ = 0.01, p = 0.93). Enteral vitamin intake from supplements was not associated with serum concentrations. Necrotising enterocolitis was associated with prolonged intravenous nutrition and may be a risk factor for high serum vitamin E. High vitamin E may be a risk factor for gastrointestinal bleeding. No differences in morbidity, mortality, or vitamin intake were observed between ethnicity groups. CONCLUSION: Serum vitamin A and E concentrations in neonatal intensive care infants did not consistently reflect intakes. Prolonged intravenous nutrition increases the risk of high serum vitamin E concentrations. Prospective studies are needed to clarify these risks and to inform targeted formulation of intravenous vitamin products for preterm infants.