Frequency of Symptomatic Zinc Deficiency in Very Low Birth Weight Infants

Background: Current concepts on zinc requirements for premature infants rely on studies dating back more than 20 years. Given that nowadays more premature infants frequently survive we aimed to obtain recent frequency data on zinc deficiency in very low birth weight (VLBW) infants. Results: 226 VLBW infants born between July 2005 and December 2009 were retrospectively included in this study. Mean gestational age (GA) was 28.7 weeks (range 23 + 0 to 38 + 0) and mean birth weight 1120g (range 354-1495). All infants received zinc supplementation according to the ESPGHAN guidelines. 26 (11.5%) patients showed clinical signs for zinc deficiency of whom 15 had serum zinc concentrations < 50 mu g/dl, 9 between 50 and 70 mu g/dl and 2 > 70 mu g/dl. Infants presenting with dermatitis had significantly lower concentrations (mean 26.7 mu g/dl, range 19-31) when compared to infants with diarrhoea or isolated peripheral oedema (35.3 mu g/dl and 51.8 mu g/dl respectively). Strongest independent risk factors were low GA, being small for GA and suffering from intestinal resection due to necrotizing enterocolitis. Frequency of zinc concentrations < 50 mu g/dl were calculated to be 6.6% in VLBW infants. Conclusions: Even though current guidelines for zinc supplementation were followed the frequency of zinc deficiency was found to be unexpectedly high in ELBW and SGA infants. Despite the retrospective nature of this single centre study, our data strongly suggest that recommendations on zinc supplementation in ELBW and SGA infants should be reviewed.