Feeding preterm infants after hospital discharge: effect of diet on body composition

Growth and body composition of infants born moderate-to-late preterm fed a protein- and mineral-enriched postdischarge formula compared with a standard term formula until 6 months corrected age, a randomized controlled trial

BACKGROUND

Infants born moderate-to-late preterm (i.e., 32 wk-35 wk 6 d gestation) are, analogous to those born very preterm, at risk of later obesity, hypertension, and diabetes. Appropriate early life nutrition is key for ensuring optimal growth and body composition, thereby mitigating potential cardiometabolic risks.

OBJECTIVES

We aimed to compare growth and body composition between infants born moderate-to-late preterm fed isocaloric but protein- and mineral-enriched postdischarge formula (PDF) or standard term formula (STF) until 6 mo corrected age (CA; i.e., after term equivalent age [TEA]).

METHODS

After enrollment (≤7 d postpartum), infants received PDF if (fortified) mother's own milk (MOM) was insufficient. At TEA, those receiving >25% of intake as formula were randomized to either continue the same PDF (n = 47) or switch to STF (n = 50); those receiving ≥75% of intake as MOM (n = 60) served as references. At TEA and 6 mo CA, we assessed anthropometry and body composition using both dual-energy x-ray absorptiometry (DXA) and air displacement plethysmography (ADP).

RESULTS

Feeding groups had similar gestational age (median [25th percentile;75th percentile]: 34.3 [33.5; 35.1] wk), birthweight (mean ± standard deviation [SD]: 2175 ± 412 g), anthropometry, and body composition at TEA. At 6 mo CA, infants fed PDF had slightly, but significantly, greater length (67.6 ± 2.5 and 66.9 ± 2.6 cm, P < 0.05) and larger head circumference (43.9 ± 1.3 and 43.4 ± 1.5 cm, P < 0.05) compared to infants fed STF. Also, infants fed PDF had higher lean mass (LM) and bone mineral content estimated by DXA (4772 ± 675 and 4502 ± 741 g; 140 ± 20 and 131 ± 23 g, respectively; P < 0.05). ADP estimates, however, were not statistically different between feeding groups.

CONCLUSIONS

Infants born moderate-to-late preterm demonstrated modest increases in length, head circumference, LM, and bone mineral content when fed PDF compared to STF for 6 mo after TEA. This trial was registered at the International Clinical Trial Registry Platform as NTR5117 and NTR NL4979.

Effect of arachidonic and docosahexaenoic acid supplementation on quality of growth in preterm infants: A secondary analysis of a randomized controlled trial

BACKGROUND & AIMS

A balanced supply of arachidonic acid (ARA) and docosahexaenoic acid (DHA) may be crucial for quality of growth in preterm infants. This secondary analysis of a randomized controlled trial aimed to determine the effect of enhanced ARA and DHA supplementation on growth and body composition in infants born before 29 weeks of gestation. Furthermore, we aimed to study associations between human milk feeding, growth patterns and body composition.

METHODS

The ImNuT-trial randomized 121 infants to receive a daily supplement with medium chain triglycerides (control) or 100 mg/kg ARA and 50 mg/kg DHA (ARA:DHA group) from the second day of life until 36 weeks postmenstrual age. Growth and body composition were evaluated up to 3 months corrected age.

RESULTS

The ARA:DHA group showed better linear growth from birth to term equivalent age compared to the control group; mean difference in z score change from birth for length was 0.74 ([95% CI, 0.17-1.3]; p = 0.010). There were no differences in growth and body composition outcomes at 3 months corrected age between the groups. An increase in z score for weight after 36 weeks postmenstrual age and breastfeeding at 3 months corrected age were the strongest positive predictors of fat mass% at 3 months corrected age (both, p < 0.001).

CONCLUSION

Early enhanced supplementation of ARA and DHA may be beneficial with respect to somatic growth in very preterm infants.

CLINICAL TRIAL REGISTRATION

The trial has been registered on www.

CLINICALTRIALS

gov, ID: NCT03555019.

Muscle Function, Body Composition, Insulin Sensitivity and Physical Activity in Adolescents Born Preterm: Impact of Gestation and Vitamin D Status

Whilst several studies have explored adolescent metabolic and cognitive function after preterm birth, few have explored muscle function and physical activity. We set out to examine the relationship between gestational age and muscle metabolism in a cohort of adolescents who were born preterm. Participants were recruited from the Newcastle preterm birth growth study cohort. They did not have severe neurological disease and were not on daily medication. Participants underwent an assessment of oxidative muscle function using phosphorus magnetic resonance spectroscopy that included the half-time for recovery of equilibrium of phosphocreatine, τ½PCr. In addition, we measured key variables that might affect muscle function including physical activity levels determined by 3-day accelerometry, body composition using air displacement plethysmography, insulin sensitivity using the homeostatic model assessment/Matsuda index and serum vitamin D concentrations. 60 adolescents (35F) median age 15.6 years (range 12.1−18.8) with a median gestation of 31 weeks (range 24 to 34 weeks) underwent a single assessment. Males were more active and spent less time in sedentary mode. Time spent in light activity was associated with insulin sensitivity (IS) (Matsuda Index; p < 0.05) but there were no strong correlations between activity levels and gestational age. Greater fat mass, waist circumference and body mass index were all associated with lower IS. Gestational age was negatively associated with adjusted measures of oxidative muscle function (τ½PCr). In a stepwise multivariate linear regression model, gestational age at birth was the most significant predictor of oxidative muscle function (p = 0.005). Higher serum vitamin D levels were also associated with faster phosphocreatine recovery time (p = 0.045). Oxidative function in the skeletal muscle of adolescents born preterm is associated with gestational age and vitamin D concentrations. Our study suggests that being born preterm may have a long-term impact on muscle metabolism.

Body composition measurement for the preterm neonate: using a clinical utility framework to translate research tools into clinical care

Body composition analysis to distinguish between fat mass and fat-free mass is an established research approach to assess nutritional status. Within neonatal medicine, preterm infant body composition is linked with later health outcomes including neurodevelopment and cardiometabolic health. Mounting evidence establishing fat-free mass as an indicator of nutritional status, coupled with the availability of testing approaches that are feasible to use in preterm infants, have enhanced interest in measuring body composition in the neonatal intensive care unit (NICU) setting. In this paper, we use the concept of clinical utility-the added value of a new methodology over current standard care-as a framework for assessing several existing body composition methodologies with potential for clinical application to preterm neonates. We also use this framework to identify remaining knowledge gaps and prioritize efforts to advance our understanding of clinically-oriented body composition testing in the NICU.

Improving long-term health outcomes of preterm infants: how to implement the findings of nutritional intervention studies into daily clinical practice

Preterm-born children are at risk for later neurodevelopmental problems and cardiometabolic diseases; early-life growth restriction and suboptimal neonatal nutrition have been recognized as risk factors. Prevention of these long-term sequelae has been the focus of intervention studies. High supplies of protein and energy during the first weeks of life (i.e., energy > 100 kcal kg-1 day-1 and a protein-to-energy ratio > 3 g/100 kcal) were found to improve both early growth and later neurodevelopmental outcome. Discontinuation of this high-energy diet is advised beyond 32-34 weeks postconceptional age to prevent excess fat mass and possible later cardiometabolic diseases. After discharge, nutrition with a higher protein-to-energy ratio (i.e., > 2.5-3.0 g/100 kcal) may improve growth and body composition in the short term.Conclusion: Preterm infants in their first weeks of life require a high-protein high-energy diet, starting shortly after birth. Subsequent adjustments in nutritional composition, aimed at achieving optimal body composition and minimizing the long-term cardiometabolic risks without jeopardizing the developing brain, should be guided by the growth pattern. The long-term impact of this strategy needs to be studied. What is Known: • Preterm infants are at risk for nutritional deficiencies and extrauterine growth restriction. • Extrauterine growth restriction and suboptimal nutrition are risk factors for neurodevelopmental problems and cardiometabolic disease in later life. What is New: • Postnatally, a shorter duration of high-energy nutrition may prevent excess fat mass accretion and its associated cardiometabolic risks and an early switch to a protein-enriched diet should be considered from 32-34 weeks postconceptional age. • In case of formula feeding, re-evaluate the need for the continuation of a protein-enriched diet, based on the infant's growth pattern.

Do preterm girls need different nutrition to preterm boys? Sex-specific nutrition for the preterm infant

Boys born preterm are recognised to be at higher risk of adverse outcomes than girls born preterm. Despite advances in neonatal intensive care and overall improvements in neonatal morbidity and mortality, boys born preterm continue to show worse short- and long-term outcomes than girls. Preterm birth presents a nutritional crisis during a critical developmental period, with postnatal undernutrition and growth-faltering common complications of neonatal intensive care. Furthermore, this preterm period corresponds to that of rapid in utero brain growth and development, and the developmental window relating to foetal programming of adult non-communicable diseases, the prevalence of which are associated both with preterm birth and sex. There is increasing evidence to show that from foetal life, boys and girls have different responses to maternal nutrition, that maternal breastmilk composition differs based on foetal sex and that early neonatal nutritional interventions affect boys and girls differently. This narrative review examines the evidence that sex is an important moderator of the outcomes of preterm nutrition intervention, and describes what further knowledge is required before providing nutrition intervention for infants born preterm based on their sex. IMPACT: This review examines the increasing evidence that boys and girls respond differently to nutritional stressors before birth, that maternal breastmilk composition differs by foetal sex and that nutritional interventions have different responses based on infant sex. Boys and girls born preterm are given standard nutritional support which does not take infant sex into account, and few studies of neonatal nutrition consider infant sex as a potential mediator of outcomes. By optimising early nutrition for boys and girls born preterm, we may improve outcomes for both sexes. We propose future studies of neonatal nutritional interventions should consider infant sex.

Advances in nutrition of the newborn infant

Nutrition of newborn infants, particularly of those born preterm, has advanced substantially in recent years. Extremely preterm infants have high nutrient demands that are challenging to meet, such that growth faltering is common. Inadequate growth is associated with poor neurodevelopmental outcomes, and although improved early growth is associated with better cognitive outcomes, there might be a trade-off in terms of worse metabolic outcomes, although the contribution of early nutrition to these associations is not established. New developments include recommendations to increase protein supply, improve formulations of parenteral lipids, and provide mineral supplements while encouraging human milk feeding. However, high quality evidence of the risks and benefits of these developments is lacking. Clinical trials are also needed to assess the effect on preterm infants of experiencing the smell and taste of milk, to determine whether boys and girls should be fed differently, and to test effects of insulin and IGF-1 supplements on growth and developmental outcomes. Moderate-to-late preterm infants have neonatal nutritional challenges that are similar to those infants born at earlier gestations, but even less high quality evidence exists upon which to base clinical decisions. The focus of research in nutrition of infants born at term is largely directed at new formula products that will improve cognitive and metabolic outcomes. Providing the most effective nutrition to preterm infants should be prioritised as an important focus of neonatal care research to improve long-term metabolic and developmental outcomes.

Nutrient-enriched formula versus standard formula for preterm infants following hospital discharge

BACKGROUND

Preterm infants are often growth-restricted at hospital discharge. Feeding nutrient-enriched formula rather than standard formula to infants after hospital discharge might facilitate 'catch-up' growth and might improve development.

OBJECTIVES

To compare the effects of nutrient-enriched formula versus standard formula on growth and development of preterm infants after hospital discharge.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (2016, Issue 8) in the Cochrane Library, MEDLINE, Embase and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; to 8 September 2016), as well as conference proceedings and previous reviews.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that compared the effects of feeding nutrient-enriched formula (postdischarge formula or preterm formula) versus standard term formula to preterm infants after hospital discharge .

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias and extracted data independently. We analysed treatment effects as described in the individual trials and reported risk ratios and risk differences for dichotomous data, and mean differences (MDs) for continuous data, with respective 95% confidence intervals (CIs). We used a fixed-effect model in meta-analyses and explored potential causes of heterogeneity by performing sensitivity analyses. We assessed quality of evidence at the outcome level using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 16 eligible trials with a total of 1251 infant participants. Trials were of variable methodological quality, with lack of allocation concealment and incomplete follow-up identified as major potential sources of bias. Trials (N = 11) that compared feeding infants with 'postdischarge formula' (energy density about 74 kcal/100 mL) versus standard term formula (about 67 kcal/100 mL) did not find consistent evidence of effects on growth parameters up to 12 to 18 months post term. GRADE assessments indicated that evidence was of moderate quality, and that inconsistency within pooled estimates was the main quality issue.Trials (N = 5) that compared feeding with 'preterm formula' (about 80 kcal/100 mL) versus term formula found evidence of higher rates of growth throughout infancy (weighted mean differences at 12 to 18 months post term: about 500 g in weight, 5 to 10 mm in length, 5 mm in head circumference). GRADE assessments indicated that evidence was of moderate quality, and that imprecision of estimates was the main quality issue.Few trials assessed neurodevelopmental outcomes, and these trials did not detect differences in developmental indices at 18 months post term. Data on growth or development through later childhood have not been provided.

AUTHORS' CONCLUSIONS

Recommendations to prescribe 'postdischarge formula' for preterm infants after hospital discharge are not supported by available evidence. Limited evidence suggests that feeding 'preterm formula' (which is generally available only for in-hospital use) to preterm infants after hospital discharge may increase growth rates up to 18 months post term.

Catch-up growth and metabolic outcomes in adolescents born preterm

BACKGROUND

Accelerated infant weight gain in individuals born full term is linked to cardiovascular risk in adulthood, but data in those born preterm are inconsistent.

OBJECTIVE

To investigate the association between weight gain in infancy and childhood with later markers of the metabolic syndrome in adolescents who were born preterm.

STUDY DESIGN

Longitudinal cohort study.

SETTING

Children born preterm with regular assessments of infant growth had auxology, body composition (dual X-ray absorptiometry), blood pressure, insulin sensitivity and lipid profile determined in adolescence.

RESULTS

We reviewed 153 children (mean gestation 30.8 weeks, median birth weight 1365 g) of whom 102 consented to venepuncture at a median age of 11.5 years. Adolescent height and weight standard deviation scores (SDS) were similar to population averages (0.01±0.92 and 0.3±1.2, respectively) and did not differ between infants when grouped according to degree of catch-up in weight gain in the immediate postdischarge period to 12 weeks of age. There were no significant associations between infant weight gain (change in weight SDS adjusted for length) and later metabolic outcome. However, there were strong associations between more rapid childhood weight gain (after 1 year of age) and subsequent body composition (higher fat mass %, fat mass index and waist circumference) and metabolic markers (higher fasting insulin, blood pressure and lower insulin sensitivity).

CONCLUSIONS

The association of rapid weight gain on health is time critical in those born preterm; in early infancy, this does not impact on metabolic status in adolescence, in contrast to rapid weight gain in childhood, which should be discouraged. However, given the critical importance of brain growth in the neonatal period and infancy, further research is needed before strategies that discourage infant weight gain or catch-up can be recommended for infants born preterm.

Effects of breast-feeding compared with formula-feeding on preterm infant body composition: a systematic review and meta-analysis

We conducted a systematic review and meta-analysis to compare the effect of breast-feeding and formula-feeding on body composition of preterm infants. We searched the literature using PubMed, Cochrane Central Library Issue, Ovid (Medline), Embase and other resources such as Google Scholar, electronic databases and bibliographies of relevant articles; two reviewers collected and extracted data independently. All the authors assessed risk of bias independently using the Newcastle-Ottawa Scale (NOS). A fixed-effects meta-analysis was undertaken with RevMan 5 software (The Cochrane Collaboration) using the inverse variance method (P≥0·05; χ 2 test). In contrast, a random-effects meta-analysis was carried out. Altogether, 630 articles were identified using search strategy, and the references within retrieved articles were also assessed. A total of six studies were included in this systematic review. In formula-fed infants, fat mass was higher at term (mean difference 0·24 (95 % CI 0·17, 0·31) kg), fat-free mass was higher at 36 weeks of gestational (mean difference 0·12 (95 % CI 0·04, 0·21) kg) and the percentage of fat mass was higher at 36 weeks of gestation (mean difference 3·70 (95 % CI 1·81, 5·59) kg) compared with breast-fed infants. Compared with breast-feeding, formula-feeding is associated with altered body composition from birth to term in preterm infants. The effects of formula-feeding on preterm infant body composition from term to 12-month corrected age are inconclusive in our study. Well-designed studies are required in the future to explore the effects of formula-feeding compared with breast-feeding.

Postnatal growth in preterm infants and later health outcomes: a systematic review

In preterm infants, poor postnatal growth is associated with adverse neurocognitive outcomes; conversely, rapid postnatal growth is supposedly harmful for future development of metabolic diseases.

CONCLUSION

In this systematic review, observational studies reported consistent positive associations between postnatal weight or head growth and neurocognitive outcomes; however, there was limited evidence from the few intervention studies. Evidence linking postnatal weight gain to later adiposity and other cardiovascular disease risk factors in preterm infants was also limited.

Post-discharge formula feeding in preterm infants: A systematic review mapping evidence about the role of macronutrient enrichment

BACKGROUND & AIMS

Preterm infants are a heterogeneous group and many accumulate growth deficits before and after initial hospital discharge. Although this is associated with worse cognitive outcome, recent meta-analyses suggest that nutrient fortification of breast milk, or the use of nutrient and energy rich formulae after discharge exert little effect on growth and neurodevelopment. However, the complexity of study design, inclusion criteria and outcome parameters, combined with differences in formula composition mean that meta-analysis may overlook important effects of differing interventions in sub-groups.

METHODS

We systematically identified evidence and mapped the information on Participants, Intervention, Comparator, and Outcome (PICO) from 31 published studies illustrating the marked heterogeneity in study design and interventions next to outcomes on (quality of) growth and neurodevelopment.

RESULTS

Despite significant heterogeneity in study design, we found that nutrient enriched diets after discharge show no negative effects but frequently improve growth parameters at some point in the course of the study, in particular for boys. The data indicates that when energy requirements are adequate, increased protein results in increased growth and lean mass (LM) accretion; In particular, higher protein to energy ratios lead to increased lean mass accretion, and increased head circumference (HC) at one year. However, improvements in neurodevelopmental outcome were rarely seen.

CONCLUSION

This comprehensive evidence mapping approach to the field provides a broad but detailed overview of the currently available evidence. Furthermore, we identified key gaps in existing knowledge on the role of nutrient enrichment in the post-discharge period.

Growth and metabolic outcome in adolescents born preterm (GROWMORE): follow-up protocol for the Newcastle Preterm Birth GRowth study (PTBGS)

Background

Preterm infants represent up to 10% of births worldwide and have an increased risk of adverse metabolic outcomes in later life. Early life exposures are key factors in determining later health but current lifestyle factors such as diet and physical activity are also extremely important and provide an opportunity for targeted intervention.

Methods/Design

This current study, GROWMORE, is the fourth phase of the Newcastle Preterm Birth Growth Study (PTBGS), which was formed from two randomised controlled trials of nutrition in early life in preterm (24–34 weeks gestation) and low birthweight infants. 247 infants were recruited prior to hospital discharge. Infant follow-up included detailed measures of growth, nutritional intake, morbidities and body composition (Dual X Ray Absorptiometry, DXA) along with demographic data until 2 years corrected age. Developmental assessment was performed at 18 months corrected age, and cognitive assessment at 9–10 years of age. Growth, body composition (DXA), blood pressure and metabolic function (insulin resistance and lipid profile) were assessed at 9–13 years of age, and samples obtained for epigenetic analysis. In GROWMORE, we will follow up a representative cohort using established techniques and novel metabolic biomarkers and correlate these with current lifestyle factors including physical activity and dietary intake. We will assess auxology, body composition (BODPOD™), insulin resistance, daily activity levels using Actigraph™ software and use ³¹P and ¹H magnetic resonance spectroscopy to assess mitochondrial function and intra-hepatic lipid content.

Discussion

The Newcastle PTBGS is a unique cohort of children born preterm in the late 1990’s. The major strengths are the high level of detail of early nutritional and growth exposures, and the comprehensive assessment over time. This study aims to examine the associations between early life exposures in preterm infants and metabolic outcomes in adolescence, which represents an area of major translational importance.

Timing of nutritional interventions in very-low-birth-weight infants: optimal neurodevelopment compared with the onset of the metabolic syndrome

Recent nutritional research in very-low-birth-weight (VLBW) infants is focused on the prevention of protein malnutrition during the first postnatal weeks. At this early age, nutritional protein fortification depends on amino acid infusion via a central vein because of the immature gastrointestinal tract. In 2010 new guidelines on nutrition were proposed by the European Society of Paediatric Gastroenterology, Hepatology, and Nutrition nutrition committee. In particular, the relative increase in the protein fraction in the nutrition of these infants aims to prevent early postnatal weight loss, to prevent morbidity, and to stimulate neurodevelopment. On the other hand, an increasing number of follow-up studies in VLBW infants indicate that, in particular, those infants who show rapid growth after preterm birth are at risk of metabolic consequences and cardiovascular disease later in life. In this review, we describe the quest to develop a customized diet that offers optimal nutrition at several time points of growth and development during the first year of life. This diet should prevent early malnutrition, enhance neurodevelopment, and limit the increase in total body fat during the first 6 mo. We question whether one type of early diet suffices for normal neurodevelopment with a normal body composition in later life or whether we need several types of diet at various stages of development.

Potential influence of total parenteral nutrition on body composition at discharge in preterm infants

OBJECTIVE

This study was undertaken to assess the potential influence of total parenteral nutrition (TPN) on body composition (BC) in preterm infants.

STUDY DESIGN

This prospective, observational study of infants born <35 weeks measured BC at discharge using air displacement plethysmography. The % body fat (BF) at discharge was correlated with variables gestational age (GA), severity of illness, days on oxygen, time to regain birth weight and duration of TPN.

RESULT

The 61 patients enrolled had a %BF at discharge of 13.9%. GA and TPN days correlated with %BF for the entire group. Multiple regression analysis identified that the time to regain birth weight added to the effect of GA, but not TPN. Isolating the influence of TPN in a subgroup of similarly aged infants (30-35 weeks) did not reveal a difference in body composition at the time of discharge between infants who did or did not receive TPN.

CONCLUSION

These findings fail to demonstrate a clear influence of TPN on the increased accrual of BF in premature infants and implicate gestational modification in nutrient/caloric utilization as a principle regulator of body composition in premature newborns.

Nutritional recommendations for the late-preterm infant and the preterm infant after hospital discharge

Early nutritional support of preterm infants is critical to life-long health and well being. Numerous studies have demonstrated that preterm infants are at increased risk of mortality and morbidity, including disturbances in brain development. To date, much attention has focused on enhancing the nutritional support of very low and extremely low birth weight infants to improve survival and quality of life. In most countries, preterm infants are sent home before their expected date of term birth for economic or other reasons. It is debatable whether these newborns require special nutritional regimens or discharge formulas. Furthermore, guidelines that specify how to feed very preterm infants after hospital discharge are scarce and conflicting. On the other hand, the late-preterm infant presents a challenge to health care providers immediately after birth when decisions must be made about how and where to care for these newborns. Considering these infants as well babies may place them at a disadvantage. Late-preterm infants have unique and often-unrecognized medical vulnerabilities and nutritional needs that predispose them to greater rates of morbidity and hospital readmissions. Poor or inadequate feeding during hospitalization may be one of the main reasons why late-preterm infants have difficulty gaining weight right after birth. Providing optimal nutritional support to late premature infants may improve survival and quality of life as it does for very preterm infants. In this work, we present a review of the literature and provide separate recommendations for the care and feeding of late-preterm infants and very preterm infants after discharge. We identify gaps in current knowledge as well as priorities for future research.

Small-for-gestational-age preterm-born infants already have lower bone mass during early infancy

BACKGROUND

In preterm-born infants, low birth weight and diminished bone accretion deteriorate peak bone mass. Whether low birth weight is already associated with decreased bone mass during infancy is unknown.

OBJECTIVE

To study the effect of birth weight on bone accretion between term age (40 weeks postmenstrual age) and six months post-term in preterm-born infants.

DESIGN

In 139 preterm-born infants (51% male, gestational age 30.3±1.5 weeks, birth weight 1341±288g) weight and whole-body bone mineral content (BMC, gram) were measured at term age and six months post-term. At birth, infants were small-for-gestational-age (SGA, n=33, weight and/or length<-2 SDS) or appropriate-for-gestational-age (AGA, n=98, weight and length≥-2 SDS).

RESULTS

At term age and six months post-term, BMC adjusted for gender and gestational age was lower in SGA than AGA infants (term age: 38.1±9.5 versus 48.6±10.1g, β=-0.26, 95% CI -0.37; -0.16, p<0.001; six months: 130.1±25.7 versus 145.4±22.9g, β=-0.16, 95% CI -0.25; -0.08, p<0.001). At six months post-term, BMC remained lower in SGA infants after adjustment for actual weight and length. Between term age and six months post-term, BMC gain adjusted for gender and gestational age was lower in SGA than AGA infants (91.7±22.8 versus 98.2±20.7g; β=-0.12, 95% CI -0.24; -0.003, p=0.044). BMC gain remained lower in SGA infants after adjustment for weight and length gain.

CONCLUSION

The first six months post-term, SGA preterms have lower bone accretion, independent of body size, suggesting that prenatal conditions for bone accretion cannot be replicated postnatally.

Nutrient-enriched formula versus standard term formula for preterm infants following hospital discharge

BACKGROUND

Preterm infants are often growth-restricted at hospital discharge. Feeding infants after hospital discharge with nutrient-enriched formula rather than standard term formula might facilitate "catch-up" growth and improve development.

OBJECTIVES

To determine the effect of feeding nutrient-enriched formula compared with standard term formula on growth and development for preterm infants following hospital discharge.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2011, Issue 4), MEDLINE, EMBASE, and CINAHL (to September 2011), conference proceedings and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared the effect of feeding preterm infants following hospital discharge with nutrient-enriched formula (post-discharge formula or preterm formula) compared with standard term formula.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

We found 15 eligible trials in which a total of 1128 preterm infants participated. The trials were of variable methodological quality with lack of allocation concealment and incomplete follow-up in some trials being the major potential sources of bias. The trials (N = 10) that compared feeding infants with "post-discharge formula" (energy density about 74 kcal/100 ml) versus standard term formula (about 67 kcal/100 ml) did not find consistent evidence of effects on growth parameters up to 12 to 18 months corrected age. The trials (N = 5) that compared feeding with "preterm formula" (about 80 kcal/100 ml) versus term formula found some evidence of higher rates of growth through infancy: weighted mean differences at 12 to 18 months corrected age about 500 g in weight, 5 to10 mm in length, and 5 mm in head circumference. Few trials assessed neurodevelopmental outcomes and these did not detect any statistically significant differences in developmental indices at 18 months corrected age. There are not yet any data on growth or development through later childhood.

AUTHORS' CONCLUSIONS

Current recommendations to prescribe "post-discharge formula" for preterm infants following hospital discharge are not supported by the available evidence. Some limited evidence exists that feeding preterm infants following hospital discharge with "preterm formula" (which is generally only available for in-hospital use) may increase growth rates up to 18 months corrected age.

Bioinformatic selection of putative epigenetically regulated loci associated with obesity using gene expression data

There is considerable interest in defining the relationship between epigenetic variation and the risk of common complex diseases. Strategies which assist in the prioritisation of target loci that have the potential to be epigenetically regulated might provide a useful approach in identifying concrete examples of epigenotype-phenotype associations. Focusing on the postulated role of epigenetic factors in the aetiopathogenesis of obesity this report outlines an approach utilising gene expression data and a suite of bioinformatic tools to prioritise a list of target candidate genes for more detailed experimental scrutiny. Gene expression microarrays were performed using peripheral blood RNA from children aged 11-13years selected from the Newcastle Preterm Birth Growth Study which were grouped by body mass index (BMI). Genes showing ≥2.0 fold differential expression between low and high BMI groups were selected for in silico analysis. Several bioinformatic tools were used for each following step; 1) a literature search was carried out to identify whether the differentially expressed genes were associated with adiposity phenotypes. Of those obesity-candidate genes, putative epigenetically regulated promoters were identified by 2) defining the promoter regions, 3) then by selecting promoters with a CpG island (CGI), 4) and then by identifying any transcription factor binding modules covering CpG sites within the CGI. This bioinformatic processing culminated in the identification of a short list of target obesity-candidate genes putatively regulated by DNA methylation which can be taken forward for experimental analysis. The proposed workflow provides a flexible, versatile and low cost methodology for target gene prioritisation that is applicable to multiple species and disease contexts.

Development of whole body adiposity in preterm infants

The long-term effects of prematurity, early diet and catch-up growth on metabolic risk and body adiposity are of increasing interest to Neonatologists. Poor growth is known to be associated with poorer neuro-developmental outcome but concern exists that increased rates of "catch-up" (or "recovery") growth may be associated with increased adiposity and the later development of metabolic syndrome. In this manuscript we review the published data on body composition in preterm infants, and present new analyses of body adiposity in preterm infants during the 12-15 months of life, and the effect of growth rate (weight gain) on body adiposity. We conclude that although preterm infants have increased adiposity at term corrected age, they generally have lower body fat than their term peers during the rest of the 12-15 months of life. Although more rapid "catch-up" growth in preterm infants during the first year of life is associated with greater body fatness than slower rates of growth, these higher rates of growth lead to body composition more similar to that of the term-born infant, than do slower rates of growth. Although more studies are needed to determine whether these short-term increases or the longer-term decreases in adiposity modify the risk on chronic diseases such as diabetes mellitus, hypertension or other components of the metabolic syndrome, the widely held concern that preterm babies have greater adiposity than their term peers, and that this is worsened by greater amounts of catch-up growth, are not supported by the available evidence.

Benefits of supplemented preterm formulas on insulin sensitivity and body composition after discharge from the neonatal intensive care unit

OBJECTIVE

To evaluate body composition and fasting insulin level in preterm infants receiving preterm formulas (higher protein plus docosahexaenoic acid) for longer periods compared with a recent historical cohort receiving these formulas for shorter periods.

STUDY DESIGN

A total of 95 infants fed preterm formula for 6 months or longer (postdischarge formula group) and 87 infants fed preterm formula only during their hospital stay (hospital formula group) were included in this arm of the study.

RESULTS

Bone mineral density, content, and lean mass were not different at 1 year and 2 years. However, in the postdischarge formula group, total fat mass (%) was lower by the second year (19.3% ± 5.3% vs 21.7% ± 4.2%; P < .01), trunk fat was lower by the first year (14.7% ± 5.0% vs 16.9% ± 4.9%; P < .005) and at the second year (14.1% ± 5.7% vs 17.2% ± 4.7%; P < .001), and fasting insulin was lower by the first year (13.2% ± 7.1% vs 17.2% ± 13.6% mIU/L; P = .06) and at the second year (13.6% ± 6.1% vs 26.4% ± 14.2%; P < .001).

CONCLUSION

Preterm infants fed formulas enriched with docosahexaenoic acid may have a better subsequent metabolic profile.

Adiposity is not altered in preterm infants fed with a nutrient-enriched formula after hospital discharge

To determine whether adiposity was altered, body size (weight, length) and composition, determined by dual energy x-ray absorptiometry, were examined in preterm infants fed with a nutrient enriched (A, n=56), a term infant (B, n=57) or the nutrient enriched (discharge and term) plus the term formula (term and 6 mo; C, n=26), and a group of breast-fed preterm infants (D, n=25) at hospital discharge, 3, 6, and 12 mo corrected age. The results were analyzed using standard statistics. One hundred sixty-four infants (birth weight=1406+/-248 g, GA=31+/-1.7 wk) were studied. All infants underwent "catch-up," but weight and length were greater in infants in group A compared with groups B, C, or D. More rapid and complete "catch-up" was paralleled by increased total nonfat and fat mass (g) but not percentage of fat mass. Changes in fat mass (g) were primarily explained by increased fat accretion on the legs. More rapid and complete "catch-up" growth, therefore, reflected increased nonfat and peripheral fat mass. These data do not support the hypothesis of increased or central adiposity in infants fed a nutrient-enriched formula after hospital discharge.

Optimal growth and lower fat mass in preterm infants fed a protein-enriched postdischarge formula

BACKGROUND AND OBJECTIVES

Postdischarge formulas with extra energy and protein improve short-term growth but may also influence long-term body composition in an unwanted manner. Energy- and protein-enriched formulas with an increased protein-to-energy ratio improves gain of lean mass. The objective of the study was to investigate whether feeding a nutrient-enriched formula without extra energy after term, usually 3 to 4 weeks after discharge, would influence growth and body composition in infancy.

METHODS

In this randomized controlled trial preterm infants were fed fortified human milk or preterm formula until term. At term, 102 infants were randomized to a nutrient-enriched formula without extra energy or standard formula until 6 months corrected age. Twenty-six infants received unfortified human milk after term. At term and 6 months corrected age, anthropometry and a dual-energy x-ray absorptiometry (DEXA) scan were performed. Lean and fat mass (FM) were corrected for height.

RESULTS

There were no differences in growth or body size between the feeding groups. Infants fed the enriched formula gained less FM and had lower FM corrected for body size at 6 months corrected age than infants fed standard formula. Infants fed human milk had lower lean mass and higher FM corrected for body size at 6 months corrected age than formula-fed infants.

CONCLUSIONS

Feeding nutrient-enriched formula without extra energy after term does not change quantity of growth but does influence type of weight gain and body composition of preterm infants. Infants fed the nutrient-enriched formula had lower FM corrected for body size at 6 months corrected age than infants fed standard formula or human milk.

Growth and bone mineralization in preterm infants fed preterm formula or standard term formula after discharge

OBJECTIVE

To evaluate growth and bone mineralization in very low birth weight (VLBW) infants fed preterm formula (PF) or term formula (TF).

STUDY DESIGN

In a double-blind prospective study, 49 preterm infants of gestational age 33 weeks or less were randomly fed PF or TF for 2 months after discharge, then all of the infants were fed TF for the next 2 months. Anthropometric and dual-energy x-ray absorptiometry data were collected at discharge and at 2 months and 4 months after discharge. Anthropometric data also were collected at 12 months postterm.

RESULTS

Four months after discharge, both body weight (6139 +/- 1254 g vs 5540 +/- 863 g; P = .03) and bone mineral content (104.4 +/- 29.2 g vs 87.5 +/- 17.1 g; P = .01) were significantly higher in the PF group compared with the TF group. At 12 months postterm, mean body weight, length, and head circumference remained higher in the PF group than in the TF group, and body mass index was similar and within the normal range in the 2 groups.

CONCLUSIONS

At 4 months after discharge, growth and mineralization were better in the VLBW infants who were fed PF during the first 2 months after discharge compared with those who were fed TF, suggesting that PF may be particularly valuable at this early stage of development.

Influence of protein and energy intakes on body composition of formula-fed preterm infants after term

The aim of the present study was to evaluate changes in body composition in 48 preterm infants in relation to protein and energy intakes from term up to 3 months of corrected age, using air displacement plethysmography. Protein intake (grams per kilogram per day) was negatively associated with percentage of fat mass at 1 month of corrected age. The high-protein-intake group showed greater gain in lean body mass gain than did the low-protein-intake group. This finding suggests that during the first month of corrected age, high protein intake results in a significantly different weight gain composition.

Postnatal growth failure in preterm infants: recovery of growth and body composition after term

BACKGROUND

Many preterm infants are significantly growth restricted at hospital discharge and are at increased risk for long-term growth failure.

AIMS

To compare growth and weight gain composition after term between preterm infants who were growth retarded and those who were not.

STUDY DESIGN

An observational longitudinal study was conducted.

SUBJECTS

35 preterm infants who showed growth retardation at term (group 1) and 26 preterm infants who did not (group 2).

OUTCOME MEASURES

Growth and body composition were assessed at term and at 1, 2, 3, 4 and 5 months of corrected age.

RESULTS

At term, and at 1, 2, and 3 months of corrected age, growth-retarded infants showed significantly lower body weight and fat mass than infants who did not develop growth retardation. The mean energy and protein intakes did not differ significantly between the two groups. Daily increases in body weight and fat mass between term and three months did not differ between the groups. However, during the fourth and fifth months, daily gains of body weight and fat mass were significantly greater in growth-retarded than in non-growth-retarded infants, and as a result, body weight and fat mass were comparable between the two groups at 4 and 5 months of corrected age.

CONCLUSIONS

In terms of growth parameters and body composition, growth-retarded preterm infants recovered from postnatal growth failure within the fourth month of corrected age.

Nutrition of preterm infants after hospital discharge

Growth failure in preterm infants remains extremely common despite advances in neonatal care. Many, or even a majority, leave the hospital with weights below the 10th centile for age. Because of this, the possibility of nutritional interventions to improve postdischarge growth has been considered. A variety of interventions have been tested in randomized controlled trials in formula-fed infants. Although the studies vary in design and in the intervention used, on balance the evidence supports the use of fortified formulas in formula-fed preterm infants after hospital discharge. Specially designed postdischarge formulas and preterm infant formulas seem equally efficacious. The situation for infants fed human milk is much less clear. Although the postdischarge growth in human milk-fed infants is not as good as in formula-fed infants, no interventions have been examined in human milk-fed infants in a randomized study, to our knowledge. We are unaware of any evidence that any of the commonly proposed nutritional interventions in human milk-fed infants after hospital discharge are either safe or efficacious. In the absence of such evidence, it seems prudent to avoid untested interventions in this population and to concentrate our efforts on the encouragement of breast-feeding after hospital discharge.

Weaning preterm infants: an open issue

Survival rates for very low birth weight (VLBW) and extremely low birth weight infants have substantially increased during the past few decades. Most of these infants pose new and difficult problems related in particular to neurodevelopmental outcome and growth impairment. In fact, a high percentage of very low birth weight infants fail to achieve their growth potential and experience postnatal growth restriction. Because of this in-hospital growth failure and nutrient deficits, correct nutritional intervention after hospital discharge must be instituted to avoid postnatal malnutrition and to correct the acquired deficit. Nutrient-enriched formulas for several months after discharge have shown some benefits, although their clinical value remains unclear. Weaning, which certainly represents a relevant source of nutrients for the preterm infant, has attracted little attention until now. There are no precise guidelines on this topic, and too often weaning practices are left totally to the parents, without considering the specific nutritional needs of the single infant.

Nutrient-enriched formula versus standard term formula for preterm infants following hospital discharge

BACKGROUND

Preterm infants are often growth-restricted at hospital discharge. Feeding infants after hospital discharge with nutrient-enriched formula rather than standard term formula might facilitate "catch-up" growth and improve development.

OBJECTIVES

To determine the effect of feeding nutrient-enriched formula compared with standard term formula on growth and development for preterm infants following hospital discharge.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group were used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2007), MEDLINE (1966 - May 2007), EMBASE (1980 - May 2007), CINAHL (1982 - May 2007), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared the effect of feeding preterm infants following hospital discharge with nutrient-enriched formula compared with standard term formula.

DATA COLLECTION AND ANALYSIS

Data was extracted using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two authors, and synthesis of data using weighted mean difference and a fixed effects model for meta-analysis.

MAIN RESULTS

Seven trials were found that were eligible for inclusion. These recruited a total of 631 infants and were generally of good methodological quality. The trials found little evidence that feeding with nutrient-enriched formula milk affected growth and development. Because of differences in the way individual trials measured and presented outcomes, data synthesis was limited. Growth data from two trials found that, at six months post-term, infants fed with nutrient-enriched formula had statistically significantly lower weights [weighted mean difference: -601 (95% confidence interval -1028, -174) grams], lengths [-18.8 (-30.0, -7.6) millimetres], and head circumferences [-10.2 ( -18.0, -2.4) millimetres], than infants fed standard term formula. At 12 to 18 months post-term, meta-analyses of data from three trials did not find any statistically significant differences in growth parameters. However, examination of these meta-analyses demonstrated statistical heterogeneity. Meta-analyses of data from two trials did not reveal a statistically significant difference in Bayley Mental Development or Psychomotor Development Indices. There are not yet any data on growth or development through later childhood.

AUTHORS' CONCLUSIONS

The available data do not provide strong evidence that feeding preterm infants following hospital discharge with nutrient-enriched formula compared with standard term formula affects growth rates or development up to 18 months post-term.

Preventing postnatal growth failure--the significance of feeding when the preterm infant is clinically stable

Nutrition guidelines and growth targets for preterm infants are currently based upon the reference standard of intrauterine growth and fetal nutrient accretion rates. This may not be an entirely appropriate standard--it is rarely achieved in clinical practice. Postnatal growth failure of very preterm infants is a universal problem with potentially significant, adverse neurological and health outcomes. The nutrient deficit that accumulates in the early weeks postdelivery when the preterm infant is clinically unstable is difficult to recover. Weight, length and head circumference measurements remain important clinical indicators of growth but composition of weight gain is emerging as a necessary measure in determining the adequacy of nutrition intake and growth. Recommended protein and energy intakes for very preterm infants are difficult to achieve with commercial human milk fortifiers and during hospitalisation, targeting the fortification of human milk to optimise the protein to energy ratio of milk feeds is necessary to ensure appropriate composition of weight gain. Postdischarge, continued fortification of human milk feeds may be required for a limited period of time for preterm infants with suboptimal weight for corrected age.

AIM AND METHODS

The following systematic review is aimed to derive evidence-based best practice guidelines for prevention of postnatal growth failure of very preterm infants who are clinically stable and growing. The focus is on reviewing the standard upon which ideal growth and nutrition guidelines are based and targeting fortification to maximise the protein to energy ratio in human milk feeds to ensure appropriate composition of weight gain. Directions for future research are provided. For the literature review the data bases Medline, EMBASE, CINAHL, the Cochrane Library and reference lists of review articles were reviewed to December 2006. A hand search of paediatric and perinatal journals was also conducted.

Randomized comparison of a nutrient-dense formula with an energy-supplemented formula for infants with faltering growth

INTRODUCTION

The practice of supplementing standard infant formula with energy for infants with faltering growth has been widespread. This increases energy density but disturbs the protein : energy ratio, and increases risks of microbial contamination and errors in feed preparation. This study aimed to compare the effectiveness of a nutrient-dense formula (NDF) with an energy-supplemented formula (ESF) in infants with faltering growth.

METHODS

In an open, parallel, randomized study, 49 infants with faltering growth were randomized to receive a NDF (4.2 kJ mL(-1)) or an ESF (4.2 kJ mL(-1)), for 6 weeks. Anthropometry, biochemistry, feed intake, stool and vomit frequency were collected.

RESULTS

No significant differences in tolerance, feed volumes or energy intakes were recorded but the NDF group received 42% more protein and 15-40% more vitamins and minerals. Blood urea concentration in the ESF group fell by 50% over the trial period, suggesting a suboptimal protein : energy ratio in the ESF feed. The NDF group retained a normal mean blood urea concentration, a higher urinary potassium concentration and did not have the significant fall in length z-score seen in the ESF group.

CONCLUSION

Increasing the energy content of normal infant formula without also increasing protein and micronutrients should not be practiced in infants with faltering growth.

Post-discharge nutrition: what does the evidence support?

Although there are no official recommendations for specific nutrient intakes in premature infants after hospital discharge, it is agreed that the goal should be to achieve the body composition and rate of growth of that of a normal fetus of the same postmenstrual age during the entire first year of life. A general recommendation to use the special formulas designed for preterm infants after hospital discharge in place of the formulas for term infants cannot be made from the available evidence at this time. Infants fed human milk after discharge are of the greatest concern as human milk does not in theory meet the requirements for growth in these infants. Such infants should remain on supplemental vitamins and Fe while breastfeeding, and growth as well as serum levels of phosphorus and alkaline phosphatase should be carefully monitored. The increased risk of preterm infants for obesity and the metabolic syndrome secondary to the metabolic/nutritional events early in life (programming) is likely to be small compared with the contribution of other risk factors, such as parental size, weight as an adolescent, and various lifestyle factors such as physical activity.

Enteral nutrition for premature infants: the role of human milk

Nutrition support of the premature infant must be designed to compensate for metabolic and gastrointestinal immaturity, immunologic insufficiency, and the demands of associated medical conditions. The beneficial effects of human milk extend to the feeding of premature infants. Although human milk enhances immunity, nutritional concerns arise because the milk might not meet the expanded nutrient requirements of very low birth weight premature infants. Human milk fortifiers are available to provide optimum nutrition. This chapter summarizes the benefits and limitations of human milk for the premature infant.

Posthospital discharge feeding for preterm infants: effects of standard compared with enriched milk formula on growth, bone mass, and body composition

BACKGROUND

Despite the theoretical benefits of nutrient-enriched formula given to preterm infants after hospital discharge, its role in reversing growth deficits after hospital discharge remains poorly defined.

OBJECTIVE

The aim was to determine the effect of different formulas on the growth, bone mass, and body composition of preterm infants after hospital discharge.

DESIGN

This was a randomized, double blind comparison of a nutrient-enriched formula (EF) and a formula for term infants (TF) given for 1 y after hospital discharge. Compared with the TF, the EF had a higher energy density and higher contents of protein, calcium, and phosphorus (by 10%, 21%, 44%, and 11%, respectively) and higher contents of almost all other nutrients (by >or=10%).

RESULTS

Birth weights of the infants were 630-1620 g (median: 1250 g) and gestational ages were 24-34 wk (median: 29 wk). TF resulted in significantly greater weight, length, head circumference measurements, and their respective z scores on the basis of age- and sex-specific norms. At the end of the study, the mean z scores for the corrected age of infants in the TF group were -0.37 for weight, 0.001 for length, and 0.50 for head circumference. The TF group also had significantly greater dual-energy X-ray absorptiometry measured bone and lean and fat mass than did the EF group (P < 0.05 for all comparisons).

CONCLUSIONS

The use of EF for preterm infants after hospital discharge shows no advantage over TF in growth, bone mineralization, and body composition. More studies are needed to determine the optimal postdischarge nutrition support for preterm infants.

Nutritional support in the premature newborn

The theory and practice of nutritional support in the premature newborn has assumed increasing importance with survival of greater numbers of very immature infants. After birth, many do not tolerate full enteral feeding until gastrointestinal motor function has matured. During this process some will develop necrotising enterocolitis (NEC), a devastating failure of adaptation to postnatal life that may result in death, or severe complications. The feeding strategy that minimises the risk of NEC remains to be defined. In addition, promoting growth rates and nutrient accretion equivalent to those achieved during fetal development while optimising neurodevelopmental and long term health outcomes represents an important challenge for neonatologists. This review will focus on the problems associated with enteral nutrition, the requirement for parenteral nutrition, and the long term consequences of early nutritional interventions, underlining the need for prolonged follow up in assessing the potential benefits of different approaches to feeding.

Nutritional status at 2 years in former infants with bronchopulmonary dysplasia influences nutrition and pulmonary outcomes during childhood

Improved survival rates for extreme prematurity have been accompanied by an increase in the incidence of bronchopulmonary dysplasia (BPD). The objective of this study was to assess factors associated with long-term nutritional and pulmonary function outcomes. The study was a cross-sectional study of 52 children who had been born prematurely, had experienced BPD, and were 4-8 y old at the time of the study. Undernutrition was defined as a Z score for weight-for-height of <-2 SD. Body composition and lung function were evaluated. Resting energy expenditure (REE) was measured using indirect calorimetry. Stepwise logistic regression was used to test for factors associated with undernutrition and pulmonary function. Eighteen children (35%) with BPD, predominantly girls, were undernourished. Undernutrition occurred within the first months of life and was associated with high REE. Multivariate analysis showed that factors significantly associated with undernutrition were female sex and undernutrition at age 2 y. Thirty-one children (60%) had abnormal lung function tests. Multivariate analysis showed that undernutrition at age 2 y was the only factor associated with the risk of developing distension of the airways. Nutritional status at age 2 y in children who had BPD in infancy influences nutritional and pulmonary outcomes in childhood.

Postdischarge nutritional therapy

Nutrient-enriched diets for preterm infants after hospital discharge (preterm formula or postdischarge formula (PDF)) results in improved growth and these differences appear to persist beyond the period of nutrient intervention. The PDF diet effect is greatest in males, possibly reflecting their higher growth rates. The critical growth epoch appears to be the first 2 months post-term, suggesting a finite period and therefore opportunity for enhanced growth. Whether the observed growth effects persist further or have consequences for other aspects of health or development requires further investigation.

Feeding preterm infants after hospital discharge: a commentary by the ESPGHAN Committee on Nutrition

Survival of small premature infants has markedly improved during the last few decades. These infants are discharged from hospital care with body weight below the usual birth weight of healthy term infants. Early nutrition support of preterm infants influences long-term health outcomes. Therefore, the ESPGHAN Committee on Nutrition has reviewed available evidence on feeding preterm infants after hospital discharge. Close monitoring of growth during hospital stay and after discharge is recommended to enable the provision of adequate nutrition support. Measurements of length and head circumference, in addition to weight, must be used to identify those preterm infants with poor growth that may need additional nutrition support. Infants with an appropriate weight for postconceptional age at discharge should be breast-fed when possible. When formula-fed, such infants should be fed regular infant formula with provision of long-chain polyunsaturated fatty acids. Infants discharged with a subnormal weight for postconceptional age are at increased risk of long-term growth failure, and the human milk they consume should be supplemented, for example, with a human milk fortifier to provide an adequate nutrient supply. If formula-fed, such infants should receive special postdischarge formula with high contents of protein, minerals and trace elements as well as an long-chain polyunsaturated fatty acid supply, at least until a postconceptional age of 40 weeks, but possibly until about 52 weeks postconceptional age. Continued growth monitoring is required to adapt feeding choices to the needs of individual infants and to avoid underfeeding or overfeeding.

Early provision of parenteral amino acids in extremely low birth weight infants: relation to growth and neurodevelopmental outcome

OBJECTIVE

To determine if postnatal growth failure exerts an adverse effect on subsequent growth and neurodevelopment.

STUDY DESIGN

A secondary analysis of 1018 infants who were enrolled in a randomized, clinical trial of glutamine supplementation was performed to determine whether early provision of parenteral amino acids (AA) is associated with better growth and neurodevelopmental outcomes. Infants were stratified by whether they were provided > or =3 g/kg per day of AA at < or =5 days of life (early; n = 182) or not (late; n = 836).

RESULTS

At 36 weeks' postmenstrual age, significant differences were found in weight, length, and head circumference in favor of the infants who received early AA; the odds of having weight less than the 10(th) percentile for age was 4-fold higher for infants in the late group. At 18 months' CA, there were no differences in weight, length, or measures of neurodevelopment between the groups; however, male infants in the late group were twice as likely to have head circumference less than the 10(th) percentile.

CONCLUSIONS

Early AA were associated with significantly better growth outcomes at 36 weeks' postmenstrual age, and fewer infants who received early AA were found to have suboptimal head growth at 18 months' CA.

High protein pre-term infant formula: effect on nutrient balance, metabolic status and growth

Several lines of evidence suggest that formula with protein content of 3.0 g/100 kcal does not fully meet the protein needs of very-low-birth weight infants. Our purpose was to compare nitrogen balance, metabolic status and growth in infants fed a standard (3.0 g/100 kcal; RegPro) and high (3.6 g/100 kcal; HiPro) protein infant formula. Infants were fed both formulas, each formula for one week in balanced cross-over design. Metabolic status was monitored throughout. Nutrient balance and plasma amino acids were determined at the end of each week. Data were analysed using a linear mixed model. Eighteen infants were studied. Nine infants received the RegPro and nine received HiPro formula first. Nitrogen intake, absorption and retention were greater with the HiPro formula. None of the infants developed uremia or metabolic acidosis but retinol-binding-protein and weight gain were greater with the HiPro formula. Increased protein accretion paralleled by better weight gain without evidence of metabolic stress indicates that a formula with a protein content of 3.6 g/100 kcal better meets protein needs in these rapidly-growing infants. Further studies are needed to determine whether these short-term outcomes will be translated into long-term benefits.

Protein requirements in preterm infants: effect of different levels of protein intake on growth and body composition

This study compares growth and body composition in preterm infants (< or =1750 g birth weight, < or =34 wk gestation) fed three iso-caloric formulas (80 kcal/100 mL) with different protein concentrations (A = 3.3 g/100 kcal, B = 3.0 g/100 kcal, C = 2.7 g/100 kcal). The study began when full enteral feeding (150 mL/kg/d) was established and lasted until term plus 12 wk corrected age (T + 12 wca). Nutrient intake was closely monitored throughout the study; daily during initial hospital stay and following discharge averaged between each clinic visit. Anthropometry and serum biochemistries were determined weekly during initial stay and at each clinic visit. Body composition was measured after hospital discharge and at T + 12 wca. Seventy-seven infants were recruited. No differences were detected in birth/enrollment characteristics between the groups. Protein intake was closely paralleled by changes in serum urea nitrogen and differed between the groups. Infants in group A were heavier and longer and had greater head circumference at discharge, but this was confounded by a slightly older corrected age in this group. There were no significant anthropometric differences at term or T + 12 wca. No differences were detected in body composition between the groups following discharge or at T + 12 wca. An intake of 3.3 g/100 kcal appears safe and may promote increased growth before initial hospital discharge. After discharge, intakes greater than 2.7 g/100 kcal do not appear to offer clear advantage. Further studies are needed to more precisely define protein requirements in these nutritionally at-risk infants.

Post-discharge nutrition for the preterm infant

Newly designed, 'enriched,' formulas are now available for the formula feeding premature infant after hospital discharge. These new formulations add to the array of milks from which to choose when the discharge of the premature infant is approaching. However, the data to support optimal or reference nutrient intakes to use for the premature infant in the post-discharge are lacking. Breastfeeding should be encouraged as its beneficial effects may be related to the duration in which it is fed. Infants at risk for growth failure in the post-discharge period, such as infants unable to consume ad libitum intakes of milk, and who already have growth faltering or abnormal nutritional indices, may benefit for the addition of enriched formula. This review summarizes the recent data and comments on recommendations on post-discharge nutrition for premature infants.

Calcium and phosphorus nutrition in preterm infants

Metabolic bone disease is a common event in preterm infants. Between 24 wk gestation and term, the fetus accrues approximately 80% of body Ca, P and Mg. Consequently, preterm infants miss in part or completely the period of greatest mineral accretion. Ca and P requirements in preterm infants are based on demands for matching intrauterine bone mineral accretion rates and on maintenance of normal serum Ca and P concentrations. Daily physical therapy may be a useful adjunct, as it is associated with a significant increase in bone mineral density and content. Osteopenia/rickets of prematurity seems to be a self-resolving disease. However, this does not imply that a period of demineralization is acceptable. While the potential long-term consequences on peak bone mass are unclear at the moment, the short-term benefits include the avoidance of fractures, less marked dolicocephaly and improved linear growth.

Body composition in preterm infants who are fed long-chain polyunsaturated fatty acids: a prospective, randomized, controlled trial

The objective of this study was to evaluate growth and body composition of premature infants who were fed formulas with arachidonic acid (ARA; 20:4n6) and docosahexaenoic acid (DHA; 22:6n3) to 1 y of gestation-corrected age (CA). Preterm infants (750-1800 g birth weight and <33 wk gestational age) were assigned within 72 h of first enteral feeding to one of three formulas: control (n = 22), DHA+ARA from fish/fungal oil [DHA+ARA(FF); n = 20], or DHA+ARA from egg/fish oil [DHA+ARA(EF); n = 18]. Human milk feeding was allowed on the basis of the mother's choice. Infants were fed breast milk and/or preterm formulas with or without 0.26% DHA and 0.42% ARA to term CA followed by breast milk or postdischarge preterm formulas with or without 0.16% DHA and 0.42% ARA to 12 mo CA. Body composition was measured by dual-energy x-ray absorptiometry. There were no significant differences among the three study groups at any time point in weight, length, or head circumference. Bone mineral content and bone mineral density did not differ among groups. At 12 mo CA, infants who were fed DHA+ARA-supplemented formulas had significantly greater lean body mass (p < 0.05) and significantly less fat mass (p < 0.05) than infants who were fed the unsupplemented control formula. The DHA+ARA-supplemented formulas supported normal growth and bone mineralization in premature infants who were born at <33 wk gestation. Preterm formulas that had DHA+ARA at the levels and ratios in this study and were fed to 1 y CA led to increased lean body mass and reduced fat mass by 1 y of age.