Selenium supplementation to prevent short-term morbidity in preterm neonates.

BACKGROUND: Selenium is an essential trace element and component of a number of selenoproteins including glutathione peroxidase, which has a role in protecting against oxidative damage. Selenium is also known to play a role in immunocompetence. Blood selenium concentrations in newborns are lower than those of their mothers and lower still in preterm infants. In experimental animals low selenium concentrations appear to increase susceptibility to oxidative lung disease. In very preterm infants low selenium concentrations have been associated with an increased risk of chronic neonatal lung disease and retinopathy of prematurity.

OBJECTIVES: To assess the benefits and harms of selenium supplementation in preterm or very low birthweight infants.

SEARCH STRATEGY: Searches were made of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2003), MEDLINE (1966-May 2003), and Embase (1980-May 2003). The reference lists of recent trials were also searched and abstracts from the Society for Pediatric Research from 1990 were hand-searched.

SELECTION CRITERIA: Randomised controlled trials which compared selenium supplementation either parenterally or enterally with placebo or nothing from soon after birth in preterm or very low birthweight infants and which reported clinical outcomes were considered for the review.

DATA COLLECTION AND ANALYSIS: Data on selenium supplementation dose, formulation and route of administration; mortality, oxygen requirement at 28 days and 36 weeks post-menstrual age, retinopathy of prematurity, and one or more episodes of sepsis; blood selenium and glutathione peroxidase concentrations at or close to 28 days, were excerpted by both reviewers independently. Data analysis was conducted according to the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS: Three eligible trials were identified. Two trials, including one trial with a much larger sample size than the others combined, were from geographical areas with low population selenium concentrations. Meta-analysis of the pooled data showed a significant reduction in the proportion of infants having one or more episodes of sepsis associated with selenium supplementation [summary RR 0.73 (0.57, 0.93); RD -0.10 (-0.17, -0.02); NNT 10 (5.9, 50)]. Supplementation with selenium was not associated with improved survival, a reduction in neonatal chronic lung disease or retinopathy of prematurity.

REVIEWER'S CONCLUSIONS: Supplementing very preterm infants with selenium is associated with benefit in terms of a reduction in one or more episodes of sepsis. Supplementation was not associated with improved survival, a reduction in neonatal chronic lung disease or retinopathy of prematurity. Supplemental doses of selenium for infants on parenteral nutrition higher than those currently recommended may be beneficial. The data are dominated by one large trial from a country with low selenium concentrations and may not be readily translated to other populations.