Vitamin A supplementation in very-preterm or very-low-birth-weight infants to prevent morbidity and mortality: a systematic review and meta-analysis of randomized trials

BACKGROUND

A previous systematic review showed that intramuscular vitamin A supplementation reduced the risk of bronchopulmonary dysplasia (BPD) in very-low-birth-weight (VLBW) infants. However, more recent studies have questioned this finding.

OBJECTIVES

Our objective was to synthesize current evidence on vitamin A supplementation in very-preterm (<32 wk gestational age) or VLBW infants and investigate the factors that may modify its efficacy.

METHODS

A systematic review was conducted using the Cochrane systematic review methodology. We included randomized controlled trials investigating vitamin A supplementation for reducing morbidity and mortality in very-preterm or VLBW infants. Certainty of evidence was assessed using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations. Prespecified subgroup analyses assessed factors that may modify the effects of vitamin A supplementation.

RESULTS

We included 17 studies (n = 2471) in the qualitative and 15 studies (n = 2248) in the quantitative synthesis. Moderate-certainty evidence suggested a beneficial effect of vitamin A for decreasing the risk of BPD at 36 wk postmenstrual age (RR: 0.83; 95% CI: 0.74, 0.93; numbers needed to treat for an additional beneficial outcome: 16; 95% CI: 9, 53; 9 studies, n = 1752; P = 0.002). Subgroup analysis suggested that the beneficial effect was limited to infants with baseline vitamin A intake <1500 IU · kg-1 · d-1. Both enteral and parenteral routes were effective. Vitamin A supplementation did not have adverse effects and did not alter mortality before discharge (12 studies, n = 1917) or neurodevelopmental outcomes at 18-22 mo (1 study, n = 538).

CONCLUSIONS

The benefit of vitamin A supplementation for reducing BPD is likely to be limited to infants with baseline vitamin A intake <1500 IU · kg-1 · d-1 and is not affected by the route of administration.

Gut microbiota in neonates with congenital gastrointestinal surgical conditions: a prospective study

BACKGROUND

There is limited information on gut microbiota of neonates with congenital gastrointestinal surgical conditions (CGISCs) available.

METHODS

This study compared stool microbiota and short-chain fatty acids (SCFAs) of 37 term infants with CGISCs with 36 term healthy infants (HIs). Two stool samples were collected from each infant: as soon as possible after birth (week 1) and 10-14 days of life (week 2).

RESULTS

Bacterial richness and alpha diversity were comparable between CGISCs and HIs at week 1 and week 2 (all p > 0.05). Beta diversity analysis revealed that at week 1, CGISCs had similar community structures to HIs (p = 0.415). However, by week 2, community structures of CGISCs were significantly different from HIs (p = 0.003). At week 1, there were no significant differences in the relative abundances of genera Bifidobacterium and Bacteroides between CGISCs and HIs. At week 2, the relative abundance of Bifidobacterium was significantly lower in CGISCs (mean percentage 7.21 ± 13.49 vs. 28.96 ± 19.6; p = 0.002). Bacteroides were also less abundant in the CGISC group (mean percentage 0.12 ± 0.49 vs. 6.59 ± 8.62; p = 0.039). Relative abundance of genera Pseudomonas and Escherichia-Shigella were higher in CGISCs. At week 2, stool concentrations of all SCFAs were lower in CGISCs (all p < 0.001).

CONCLUSIONS

During hospitalization, neonates with CGISCs develop gut dysbiosis and deficiency of SCFAs.

IMPACT

During hospitalisation, neonates with congenital gastrointestinal surgical conditions develop gut dysbiosis with deficiency of Bifidobacteria and Bacteroides and increased abundance of Escherichia-Shigella and Pseudomonas. They also have low levels of short chain fatty acids in their stools compared to healthy infants. This is the first study evaluating the gut microbiota using 16S ribosomal RNA sequencing methods and stool short chain fatty acids in neonates with congenital gastrointestinal surgical conditions and comparing them to healthy infants. The findings of this study will pave the way for randomised trials of bifidobacterial supplementation in neonates with congenital gastrointestinal surgical conditions.

Gastric emptying of different meal volumes of identical composition in preterm infants: a time series analysis

BackgroundPreterm infants' meals typically progress to higher volumes over time. Knowledge of gastric emptying (GE) responses to differing meal volumes may inform enteral feeding management. We examined the effect of meal volume and composition on preterm GE.MethodsForty infants were studied at 33.3±1.4 (29.7-35.6) weeks postmenstrual age when fully enteral fed (target 150 ml/kg/day). Intraindividual comparisons of GE were made for paired meals of 100% and 75% prescribed volume and identical composition of mother's own milk (n=21) and pasteurized donor human milk (n=19). Serial stomach ultrasound images were used to calculate gastric residual volumes (GRVs) and remaining meal proportions (% meal).ResultsGE was faster in the early postprandial period and slowed over time (P<0.001). Reduced volume meals had slower GE rates and lower GRV (P<0.001). Serial postprandial % meal was similar between reduced and full volume meals (P=0.41). Higher milk casein concentration was associated with slower GE (P=0.04). Complete gastric emptying (GRV=0 ml) was more common in infants fed at 3 h intervals compared with those fed every 2 h (P=0.002).ConclusionEarly postprandial GE is more rapid for larger meal volumes. Stable preterm infants may tolerate feeding of a 3 h meal volume at shorter intervals.

High frequency jet ventilation in preterm infants: experience from Western Australia

Objective: To assess if high frequency jet ventilation (HFJV) is associated with reduced odds of death or discharge home on oxygen in preterm infants. Methods: A case control study (1 February 2010 - 1 June 2014) comparing the primary outcome as "death or discharge home on oxygen" in preterm infants who needed HFJV (Cases) versus those who did not (Controls). Controls were matched to cases (1:1) on gestation, birthweight, gender, place of birth, growth status, antenatal glucocorticoids, and dexamethasone as treatment for severe bronchopulmonary dysplasia (BPD). Logistic regression analysis was used to control for confounders. Results: Data on all preterm infants who needed HFJV (Cases: n = 50) and 50 controls during the study period were analysed. Primary outcome was more frequent in cases versus controls, but not significant after adjusting for mean airway pressure and adjuvant therapy (e.g. diuretics) [aOR: 1.46 (0.23-9.14), p = .687]. Death before discharge [odds ratios (OR): 6.00 (1.34-55.2), p = .013] was more frequent in cases; discharge on home oxygen [OR: 0.88 (0.27-2.76), p = 1.000] was comparable between groups. Duration of oxygen [adjusted hazard ratios (aHR): 1.23 (0.69-2.17), p = .475] and incidence of treatment warranting retinopathy of prematurity [aOR: 0.10 (0.01-1.96), p = .127] was not significant between cases versus controls. Conclusions: HFJV was not associated with reduced odds of death or discharge home on oxygen in preterm infants in our study. Adequately powered randomized trials are required to assess the efficacy and safety of HFJV in preterm infants.

Benefits of Bifidobacterium breve M-16V Supplementation in Preterm Neonates - A Retrospective Cohort Study

Background

Systematic reviews of randomised controlled trials report that probiotics reduce the risk of necrotising enterocolitis (NEC) in preterm neonates.

Aim

To determine whether routine probiotic supplementation (RPS) to preterm neonates would reduce the incidence of NEC.

Methods

The incidence of NEC ≥ Stage II and all-cause mortality was compared for an equal period of 24 months ‘before’ (Epoch 1) and ‘after’ (Epoch 2) RPS with Bifidobacterium breve M-16V in neonates <34 weeks. Multivariate logistic regression analysis was conducted to adjust for relevant confounders.

Results

A total of 1755 neonates (Epoch I vs. II: 835 vs. 920) with comparable gestation and birth weights were admitted. There was a significant reduction in NEC ≥ Stage II: 3% vs. 1%, adjusted odds ratio (aOR) = 0.43 (95%CI: 0.21–0.87); ‘NEC ≥ Stage II or all-cause mortality’: 9% vs. 5%, aOR = 0.53 (95%CI: 0.32–0.88); but not all-cause mortality alone: 7% vs. 4%, aOR = 0.58 (95% CI: 0.31–1.06) in Epoch II. The benefits in neonates <28 weeks did not reach statistical significance: NEC ≥ Stage II: 6% vs. 3%, aOR 0.51 (95%CI: 0.20–1.27), ‘NEC ≥ Stage II or all-cause mortality’, 21% vs. 14%, aOR = 0.59 (95%CI: 0.29–1.18); all-cause mortality: 17% vs. 11%, aOR = 0.63 (95%CI: 0.28–1.41). There was no probiotic sepsis.

Conclusion

RPS with Bifidobacterium breve M-16V was associated with decreased NEC≥ Stage II and ‘NEC≥ Stage II or all-cause mortality’ in neonates <34 weeks. Large sample size is required to assess the potential benefits of RPS in neonates <28 weeks.

Probiotic Supplementation and Late-Onset Sepsis in Preterm Infants: A Meta-analysis

CONTEXT

Late-onset sepsis (LOS) is a major cause of mortality and morbidity in preterm infants. Despite various preventive measures, its incidence continues to remain high, hence the urgent need for additional approaches. One such potential strategy is supplementation with probiotics. The updated Cochrane Review (2014) did not find benefits of probiotics in reducing the risk of LOS in preterm infants (19 studies, N = 5338). Currently there are >30 randomized controlled trials (RCTs) of probiotics in preterm infants that have reported on LOS.

OBJECTIVES

To conduct a systematic review including all relevant RCTs.

DATA SOURCES

PubMed, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health Literature, and E-abstracts from the Pediatric Academic Society meetings and other pediatric and neonatal conference proceedings were searched in June and August 2015.

STUDY SELECTION

RCTs comparing probiotics versus placebo/no probiotic were included.

DATA EXTRACTION

Relevant data were extracted independently by 3 reviewers.

RESULTS

Pooled results from 37 RCTs (N = 9416) using fixed effects model meta analysis showed that probiotics significantly decreased the risk of LOS (675/4852 [13.9%] vs 744/4564 [16.3%]; relative risk, 0.86; 95% confidence interval, 0.78-0.94; P = .0007; I(2) = 35%; number needed to treat, 44). The results were significant even after excluding studies with high risk of bias.

CONCLUSIONS

Probiotic supplementation reduces the risk of LOS in preterm infants.

Eating behaviour of children 1.5-3.5 years born preterm: parents' perceptions

OBJECTIVE

To investigate parents' perceptions of the eating behaviour of toddlers born preterm.

METHODS

A mailed, self-administered questionnaire was sent to parents of infants born between July 1994 and July 1996 with gestational ages less than 32 weeks who had been admitted to the Neonatal Unit at Flinders Medical Centre.

RESULTS

Responses were received for 95 subjects (response rate 70%) with a mean +/- SD gestational age of 29.2 +/- 2.1 weeks, birthweight of 1243 +/- 296 g and median corrected age of 134 weeks (range 84-185 weeks) at the time of study. Seventy-eight per cent of parents were concerned about the quality of food intake and 45% wished to change their child's eating behaviour. Although only 20% of parents identified their toddlers as being fussy eaters, food refusal was reported by 58% of respondents, and 51% and 69% used food rewards or coaxing, respectively, to encourage intake. Parents of toddlers who had received home gavage feeding (n = 5) or had a respiratory or neurological disability (n = 16), reported poorer feeding indicators.

CONCLUSIONS

Programmes providing information on normal toddler eating behaviour and strategies to promote positive feeding practices may reassure parents and promote development of food preferences and eating behaviours consistent with long-term healthy eating habits. Special emphasis should be placed on children with a disability or children who have received home gavage feeding.

Indicators of selenium status in Australian infants

OBJECTIVE

To provide the first Australian data for the commonly used indicators of selenium (Se) status including plasma and erythrocyte Se and erythrocyte glutathione peroxidase (GSHPx) activity in newborn term and preterm infants from Adelaide, South Australia. Plasma Se levels from adults from Adelaide and Tasmania are also reported.

METHODOLOGY

Descriptive, cross-sectional study of the indicators of Se status of newborn Australian preterm and term infants.

RESULTS

Mean (+/- SD) plasma Se concentrations in the first 5 days of life for term (n = 48) and preterm (n = 90) infants were similar at 33 +/- 11 and 29 +/- 14 microg/L, respectively. Glutathione peroxidase activity was lower in preterm than term infants (P < 0.001). Erythrocyte Se was lower in male (n = 74) compared with female (n = 57) infants (491 +/- 98 vs 561 +/- 134 ng/g Hb; P < 0.001). Adelaide adult plasma Se levels were 88 +/- 20 microg/L and higher than those of adult Tasmanian blood donors (77 +/- 13 microg/l, P < 0.05).

CONCLUSIONS

These data indicate that values for indicators of Se status of Australian infants and adults are at the lower end of the international range. This article highlights the paucity of Australian data on the Se content in the food supply and the Se status of the Australian population. Given the increasing range and complexity of the biological roles of Se and the emerging evidence that Se may have important roles in prevention of cancer and other disorders, further data are required to clarify the Se status of Australians.

Developmental sensitivity of the piglet brain to docosahexanoic acid

Human formula-fed infants have a lower concentration of docosahexanoic acid (DHA) in cerebral cortex compared with breast-fed infants. It is uncertain whether this biochemical deficit is reversible in later infancy. We used a piglet model to determine whether a critical window exists for the deposition of DHA in cerebral cortex during early postnatal development. Milk formula supplemented with DHA was fed to piglets for one of two 14-day periods commencing at either 2 or 16 d of life (early or late supplementation). Comparison of cortical DHA levels in response to supplemented formula was made with age-matched piglets receiving a control formula devoid of DHA. The level of DHA incorporated into whole brain during supplemented formula-feeding seemed to be less with increasing postnatal age. However, when cerebral cortex was examined, dietary DHA was efficiently incorporated during both early and late supplementation periods. Thus, analysis of whole brain was misleading, emphasizing the need to consider the effect of myelination when interpreting developmental changes in brain fatty acids. We conclude that the piglet cerebral cortex is responsive to dietary DHA during the postnatal phase of the brain growth spurt. The lower cortical DHA levels of human formula-fed infants may, therefore, be reversible in later infancy. Plasma phospholipid DHA levels were approximately doubled and liver phospholipid DHA levels increased 50% relative to starting values during control formula-feeding. This suggests a higher rate of DHA synthesis in the piglet in comparison with the human infant, which may be an important limitation of the piglet model.