Preterm birth and body composition at term equivalent age: a systematic review and meta-analysis

Adiposity and Fat-Free Mass of Children Born with Very Low Birth Weight Do Not Differ in Children Fed Supplemental Donor Milk Compared with Those Fed Preterm Formula

BACKGROUND

Many mothers of very-low-birth-weight (VLBW) infants (<1500 g) are unable to provide sufficient breast milk, and supplemental pasteurized donor human milk (donor milk) or preterm formula is required. The composition of donor milk differs from that of mother's milk and infants fed with donor milk often exhibit slower growth during hospitalization. The long-term impact of nutrient-enriched donor milk on growth, body composition, or blood pressure is unknown.

OBJECTIVE

We aimed to determine the effects of nutrient-enriched donor milk compared with preterm formula on growth, body composition, and blood pressure of children born preterm and with VLBW. Associations with in-hospital mother's milk intake were explored.

METHODS

This study was a follow-up of children at 5.5-y of age who participated in a randomized controlled trial evaluating the effect of nutrient-enriched donor milk (commencing at ≥120 mL·kg-1·d-1) or preterm formula fed as a supplement when mother's milk was unavailable. The trial intervention lasted 90 d or until hospital discharge, whichever occurred first. In this follow-up investigation, differences in total body fat percentage determined by using air displacement plethysmography (primary outcome), fat-free mass, skinfold thickness, waist circumference, BMI z scores, and blood pressure] were evaluated using linear regressions.

RESULTS

Of 316 surviving infants from the earlier trial, 158 (50%) participated in the current study (53% male). Mean ± SD birth weight and gestational age were 1013 ± 264 g and 27.9 ± 2.5 wk. The median (IQR) intervention period was 67.5 d (52.0-91.0 d). Mean ± SD age and BMI z score at follow-up were 5.7 ± 0.2 y and -0.3 ± 1.2. Supplemental nutrient-enriched donor milk, compared to preterm formula, was not associated with growth, body composition, or blood pressure. In-hospital mother's milk intake was positively associated with height z score at 5.5 y (β: 0.07; 95% CI: 0.004, 0.1; P = 0.04).

CONCLUSIONS

Supplemental nutrient-enriched donor milk and preterm formula during initial hospitalization results in comparable long-term growth and body composition in young children born VLBW. This trial was registered at clinicaltrials.gov as NCT02759809 and at isrctn.com as ISRCTN35317141.

Updates on Assessment and Monitoring of the Postnatal Growth of Preterm Infants

Assessing and monitoring the physical growth of preterm infants is fundamental to NICU care. The goals of nutritional care are to approximate the growth and body composition of the healthy fetus and to support optimal brain development while minimizing future cardiometabolic risk. Both poor and excessive growth predict adverse long-term health outcomes. Growth curves are clinical tools used to assess the preterm infant's growth status. Several growth curves for preterm infants were developed in the past decade. To use them effectively, clinicians need to understand how each growth curve was developed; the underlying reference population; intended use; and strengths and limitations. Intrauterine growth curves are references that use size at birth to represent healthy fetal growth. These curves serve 2 purposes-to assign size classifications at birth and to monitor postnatal growth. The INTERGROWTH-21 ^st preterm postnatal growth standards were developed to compare the postnatal growth of preterm infants to that of healthy preterm infants rather than the fetus. Individualized weight growth curves account for the water weight loss that frequently occurs after birth. In addition, body mass index (BMI) curves are now available. In this review, we discuss the main characteristics of growth curves used for preterm infants as well as the use of percentiles, z scores, and their change over time to evaluate size and growth status. We also review the differences in body composition between preterm infants at term-equivalent age and term-born infants and the potential role of monitoring proportionality of growth using BMI curves.

Fat and Fat-Free Mass of Preterm and Term Infants from Birth to Six Months: A Review of Current Evidence

To optimize infant nutrition, the nature of weight gain must be analyzed. This study aims to review publications and develop growth charts for fat and fat-free mass for preterm and term infants. Body composition data measured by air displacement plethysmography (ADP) and dual energy X-ray absorptiometry (DXA) in preterm and term infants until six months corrected age were abstracted from publications (31 December 1990 to 30 April 2019). Age-specific percentiles were calculated. ADP measurements were used in 110 studies (2855 preterm and 22,410 term infants), and DXA was used in 28 studies (1147 preterm and 3542 term infants). At term age, preterm infants had higher percent-fat than term-born infants (16% vs. 11%, p < 0.001). At 52 weeks postmenstrual age (PMA), both reached similar percent-fat (24% vs. 25%). In contrast, at term age, preterm infants had less fat-free mass (2500 g vs. 2900 g) by 400 g. This difference decreased to 250 g by 52 weeks, and to 100 g at 60 weeks PMA (5000 g vs. 5100 g). DXA fat-free mass data were comparable with ADP. However, median percent-fat was up to 5% higher with DXA measurements compared with ADP with PMA > 50 weeks. There are methodological differences between ADP and DXA measures for infants with higher fat mass. The cause of higher fat mass in preterm infants at term age needs further investigation.

Differential regulation of mTORC1 activation by leucine and β-hydroxy-β-methylbutyrate in skeletal muscle of neonatal pigs

Leucine (Leu) and its metabolite β-hydroxy-β-methylbutyrate (HMB) stimulate mechanistic target of rapamycin (mTOR) complex 1 (mTORC1)-dependent protein synthesis in the skeletal muscle of neonatal pigs. This study aimed to determine whether HMB and Leu utilize common nutrient-sensing mechanisms to activate mTORC1. In study 1, neonatal pigs were fed one of five diets for 24 h: low protein (LP), high protein (HP), or LP supplemented with 4 (LP+HMB4), 40 (LP+HMB40), or 80 (LP+HMB80) μmol HMB·kg body wt^-1·day^-1. In study 2, neonatal pigs were fed for 24 h: LP, LP supplemented with Leu (LP+Leu), or HP diets delivering 9, 18, and 18 mmol Leu·kg body wt^-1·day^-1, respectively. The upstream signaling molecules that regulate mTORC1 activity were analyzed. mTOR phosphorylation on Ser2448 and Ser2481 was greater in LP+HMB40, LP+HMB80, and LP+Leu than in LP and greater in HP than in HMB-supplemented groups (P < 0.05), whereas HP and LP+Leu were similar. Rheb-mTOR complex formation was lower in LP than in HP (P < 0.05), with no enhancement by HMB or Leu supplementation. The Sestrin2-GATOR2 complex was more abundant in LP than in HP and was reduced by Leu (P < 0.05) but not HMB supplementation. RagA-mTOR and RagC-mTOR complexes were higher in LP+Leu and HP than in LP and HMB groups (P < 0.05). There were no treatment differences in RagB-SH3BP4, Vps34-LRS, and RagD-LRS complex abundances. Phosphorylation of Erk1/2 and TSC2, but not AMPK, was lower in LP than HP (P < 0.05) and unaffected by HMB or Leu supplementation. Our results demonstrate that HMB stimulates mTORC1 activation in neonatal muscle independent of the leucine-sensing pathway mediated by Sestrin2 and the Rag proteins.NEW & NOTEWORTHY Dietary supplementation with either leucine or its metabolite β-hydroxy-β-methylbutyrate (HMB) stimulates protein synthesis in skeletal muscle of the neonatal pig. Our results demonstrate that both leucine and HMB stimulate mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) phosphorylation in neonatal muscle. This leucine-stimulated process involves dissociation of the Sestrin2-GATOR2 complex and increased binding of Rag A/C to mTOR. However, HMB's activation of mTORC1 is independent of this leucine-sensing pathway.

Body composition in very preterm infants before discharge is associated with macronutrient intake

Very preterm infants experience poor postnatal growth relative to intra-uterine growth rates but have increased percentage body fat (%fat). The aim of the present study was to identify nutritional and other clinical predictors of infant %fat, fat mass (FM) (g) and lean mass (LM) (g) in very preterm infants during their hospital stay. Daily intakes of protein, carbohydrate, lipids and energy were recorded from birth to 34 weeks postmenstrual age (PMA) in fifty infants born <32 weeks. Clinical illness variables and anthropometric data were also collected. Body composition was assessed at 34–37 weeks PMA using the PEA POD Infant Body Composition System. Multiple regression analysis was used to identify independent predictors of body composition (%fat, FM or LM). Birth weight, birth weight z-score and PMA were strong positive predictors of infant LM. After adjustment for these factors, the strongest nutrient predictors of LM were protein:carbohydrate ratios (102–318 g LM/0·1 increase in ratio, P = 0·006–0·015). Postnatal age (PNA) and PMA were the strongest predictors of infant FM or %fat. When PNA and PMA were accounted for a higher intake of energy (–1·41 to –1·61 g FM/kJ per kg per d, P = 0·001–0·012), protein (–75·5 to –81·0 g FM/g per kg per d, P = 0·019–0·038) and carbohydrate (–27·2 to –30·0 g FM/g per kg per d, P = 0·012–0·019) were associated with a lower FM at 34–37 weeks PMA. Higher intakes of energy, protein and carbohydrate may reduce fat accumulation in very preterm infants until at least 34–37 weeks PMA.

Lean Tissue Deficit in Preterm Infants Persists up to 4 Months of Age: Results from a Swedish Longitudinal Study

BACKGROUND

At term-equivalent age, infants born prematurely are shorter, lighter and have more adipose tissue compared to term counterparts. Little is known on whether the differences in body composition persist in later age.

METHODS

We prospectively recruited 33 preterm infants (<32 weeks gestational age, mean gestational age 28.1 weeks) and 69 term controls. Anthropometry and body composition (air displacement plethysmography) were monitored up to 4 months of age. Nutrient intakes from preterm infants were collected from clinical records.

RESULTS

At 4 months of age preterm infants were lighter and shorter than term controls (mean weight-for-age z-score: -0.73 vs. 0.06, p = 0.001; mean length-for-age z-score: -1.31 vs. 0.29, p < 0.0001). The significantly greater percentage of total body fat seen in preterm infants at term-equivalent age (20.2 vs. 11.7%, p < 0.0001) was no longer observed at 4 months. A deficit of fat-free mass persisted until 4 months of age (fat-free mass at term-equivalent age: 2.71 vs. 3.18 kg, p < 0.0001; at 4 months: 4.3 vs. 4.78 kg, p < 0.0001). The fat mass index and fat-free mass index (taking length into account) did not differ between the groups. Nutrition had little effect on body composition. Higher protein intake at week 2 was a negative predictor of fat-free mass at discharge.

CONCLUSIONS

At 4 months corrected age, preterm infants were both lighter and shorter than term controls and the absolute fat-free mass deficit remained until this age. Little effect of nutrition on body composition was observed.

How does gestational age affect growth and body composition of preterm twins?

BACKGROUND

Twins experience altered growth compared to singletons. The primary aim of this study was to compare growth and body composition (BC) of twin and singleton preterm infants from birth to 3 months according to gestational age (GA). Secondary aims were to evaluate the effect of chorionicity and mode of feeding on twins' BC.

METHODS

Anthropometric measurements and BC were performed at term and 3 months in preterm infants (GA < 37 weeks). Infants were categorized as: extremely, very, moderate and late preterm infants. Chorionicity was assigned as monochorionic, dichorionic or multichorionic. Mode of feeding was recorded as any human milk feeding vs formula feeding.

RESULTS

Five hundred and seventy-six preterm infants were included (223 twins). Late-preterm twins were lighter and shorter at each study point; fat-free mass (FFM) was lower in these infants at each study point, compared to singletons. No differences were found between twins and singleton on the other category. Multichorionic infants had an FFM deficit compared to monochorionic and dichorionic at term, whereas no differences were found at 3 months. FFM at term was negatively associated with being twin and formula-fed.

CONCLUSIONS

Twins and singletons born before 34 weeks' GA showed similar anthropometry and BC. Conversely, twin late-preterm infants showed different growth and BC compared to singletons.

Adult-Onset Diseases in Low Birth Weight Infants: Association with Adipose Tissue Maldevelopment

Low birth weight (LBW) infants have higher risk of developing insulin resistance and its comorbidities later in life. The concept of “developmental origins of health and disease” suggests that intrauterine and postnatal environments have an important role in increasing these risks. The risk of such adult-onset diseases in LBW infants might be associated with adipose tissue maldevelopment including altered body composition and increased amount of visceral fat, which is the same mechanism as that in children and adults with metabolic syndrome. However, LBW infants often have different characteristics: they are not always overweight or obese over their life course. The inconsistency might be associated with the thrifty phenotype, which is produced in response to impaired growth potential and decreased lean body mass. LBW infants tend to be obese within the limits of impaired growth potential. Through our previous investigations evaluating longitudinal changes in adiponectin levels at an early stage of life, we speculated that probably, the intrauterine life of term infants or the period up to term-equivalent age in preterm infants might be the key age for the development of adipose tissues including fat cells. Because of that, we hypothesized that the smaller number of adipocytes in LBW infants might be associated with overloading of single adipocytes and impaired adipose tissue expandability. The possible mechanisms are discussed from the perspective of adipose tissue maldevelopment in LBW infants.

Neonatal body composition: crossectional study in healthy term singletons in Germany

BACKGROUND

During pregnancy, a variety of factors can influence fetal growth and development. Intrauterine growth may impact on later life and health. Neonatal body composition may be a more sensitive marker for the intrauterine environment than established anthropometric parameters at birth.

METHODS

To study neonatal body composition determined by air displacement plethysmography in healthy, term singletons as national reference data, and to establish factors impacting on neonatal body composition in this population. This prospective cross-sectional observational study included 271 healthy, full-term, singletons born between June 2014 and July 2015. Body composition was measured within 96 h of birth using air displacement plethysmography.

RESULTS

Median (Q1, Q2) fat mass / total body mass (BF%) in German singletons was 10.8% (7.7-13.4) and fat free mass (FFM) 2843 g (2606-3099). Female infants had significantly increased BF% compared to male infants (11.2% (8.7-14.0) vs. 9.6% (7.2-12.1)). On multiple regression analysis, BF% and fat mass increased with female gender, maternal pre-pregnancy body mass index, non-smoking mother and parity, whereas FFM increased with male gender and increasing gestational age at birth. Gestational weight gain category, birth mode, and postnatal age at measurement were not associated with BF%, FFM or fat mass.

CONCLUSIONS

We generated BF% and FFM centiles for healthy, term, singletons born in Germany; these are similar to those found in other European countries. Infant body composition at birth was associated with modifiable (pre-pregnancy body mass index, smoking), and given factors (gender, gestational age at birth, parity).

ANALYSIS OF THE DIFFERENCES BETWEEN THE PRESCRIBED AND THE ADMINISTERED DIET TO PRETERM INFANTS USING AN ELECTRONIC TOO

ABSTRACT Objective: To create an electronic instrument in order to analyze the adequacy of the preterm infants’ nutritional therapy, checking the difference between the prescribed and the administered diet. Methods: A prospective and observational study on newborns with birthweight ≤1,500g and/or gestational age ≤32 weeks, without congenital malformations. The electronic instrument was developed based on Microsoft Excel 2010 spreadsheets and aimed at automatically calculating body weight gain, calories and macronutrients received daily by each patient from parenteral nutrition, intravenous hydration and enteral feedings. The weekly means of each nutrient were used to compare the prescribed and administered diets. Results: To evaluate the instrument, 60 newborns with a birth weight of 1,289±305 g and a gestational age of 30±2 weeks were included. Of them, 9.6% had restricted growth at birth and 55% at discharge. The median length of stay was 45±17 days. There were significant differences between prescribed and administered diet for all of the macronutrients and for total calories in the first three weeks. The lipid was the macronutrient with the greatest percentage error in the first week of life. Conclusions: The use of a computational routine was important to verify differences between the prescribed and the administered diet. This analysis is necessary to minimize calculation errors and to speed up health providers’ decisions about the nutritional approach, which can contribute to patients’ safety and to good nutritional practice. Very low birth weight infants are extremely vulnerable to nutritional deficiencies and any reduction in macronutrients they receive may be harmful to achieve satisfactory growth.

Prematurity blunts the feeding-induced stimulation of translation initiation signaling and protein synthesis in muscle of neonatal piglets

Postnatal growth of lean mass is commonly blunted in preterm infants and may contribute to short- and long-term morbidities. To determine whether preterm birth alters the protein anabolic response to feeding, piglets were delivered at term or preterm, and fractional protein synthesis rates (K_s) were measured at 3 days of age while fasted or after an enteral meal. Activation of signaling pathways that regulate protein synthesis and degradation were determined. Relative body weight gain was lower in preterm than in term. Gestational age at birth (GAB) did not alter fasting plasma glucose or insulin, but when fed, plasma insulin and glucose rose more slowly, and reached peak value later, in preterm than in term. Feeding increased K_s in longissimus dorsi (LD) and gastrocnemius muscles, heart, pancreas, and kidney in both GAB groups, but the response was blunted in preterm. In diaphragm, lung, jejunum, and brain, feeding increased K_s regardless of GAB. Liver K_s was greater in preterm than term and increased with feeding regardless of GAB. In all tissues, changes in 4EBP1, S6K1, and PKB phosphorylation paralleled changes in K_s. In LD, eIF4E·eIF4G complex formation, phosphorylation of TSC2, mTOR, and rpS6, and association of mammalian target of rapamycin (mTOR1) complex with RagA, RagC, and Rheb were increased by feeding and blunted by prematurity. There were no differences among groups in LD protein degradation markers. Our results demonstrate that preterm birth reduces weight gain and the protein synthetic response to feeding in muscle, pancreas, and kidney, and this is associated with blunted insulin- and/or amino acid-induced translation initiation signaling.

Associations of Growth and Body Composition with Brain Size in Preterm Infants

OBJECTIVE

To assess the association of very preterm infants' brain size at term-equivalent age with physical growth from birth to term and body composition at term.

STUDY DESIGN

We studied 62 infants born at <33 weeks of gestation. At birth and term, we measured weight and length and calculated body mass index. At term, infants underwent air displacement plethysmography to determine body composition (fat and fat-free mass) and magnetic resonance imaging to quantify brain size (bifrontal diameter, biparietal diameter, transverse cerebellar distance). We estimated associations of physical growth (Z-score change from birth to term) and body composition with brain size, adjusting for potential confounders using generalized estimating equations.

RESULTS

The median gestational age was 29 weeks (range, 24.0-32.9 weeks). Positive gains in weight and body mass index Z-score were associated with increased brain size. Each additional 100 g of fat-free mass at term was associated with larger bifrontal diameter (0.6 mm; 95% CI, 0.2-1.0 mm), biparietal diameter (0.7 mm; 95% CI, 0.3-1.1 mm), and transverse cerebellar distance (0.3 mm; 95% CI, 0.003-0.5 mm). Associations between fat mass and brain metrics were not statistically significant.

CONCLUSIONS

Weight and body mass index gain from birth to term, and lean mass-but not fat-at term, were associated with larger brain size. Factors that promote lean mass accrual among preterm infants may also promote brain growth.

Exposure to placental insufficiency alters postnatal growth trajectory in extremely low birth weight infants

Growth in the immediate postnatal period for extremely low birth weight (ELBW, birth weight < 1000 g) infants is an important topic in neonatal medicine. The goal is to ensure adequate postnatal growth and to minimize complications resulting from suboptimal growth. Past efforts have focused on postnatal nutrition as well as on minimizing comorbidities. It has not been systematically assessed whether antenatal factors play a role in postnatal growth. In this report, we conducted a retrospective study on 91 maternal-neonatal pairs. We prospectively collected maternal and neonatal demographic data, neonatal nutrition in the first 7 days of life and after enteral nutrition is fully established, comorbidity data, as well as weight data from birth to 50 weeks corrected gestational age. We developed a linear mixed-effects model to examine the role of placental insufficiency, as defined by fetal Doppler studies, in postnatal weight z-score trajectory over time in the ELBW population. We relied on Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) for model selection. Interestingly, the selected model included a quadratic term of time and a placental insufficiency-by-time interaction term. In a covariate analysis, AIC and BIC both favored a model that included calories intake in the first 7 days of life and the total duration of antibiotics as fixed-effects, but not their interaction terms with time. Overall, we demonstrated for the first time that placental insufficiency, an antenatal factor, is a major determinant of postnatal weight trajectory in the ELBW population. Prospective studies are warranted to confirm our findings.

Cohort study showed that growth rate increment has not been enough to prevent growth retardation of preterm infants and raised concerns about unbalanced growth

AIM

We describe the postnatal weight gain, linear and head growth trends of surviving preterm infants from 2005 to 2017.

METHODS

Multicentre cohort study, including surviving preterm infants <32 weeks (n = 21 084), from the Spanish Neonatal Network database, without major congenital malformations who were less than 50 weeks postmenstrual age at discharge. Outcomes were weight gain (g/kg/day), linear and head growth (cm/week) and changes in weight, length and head circumference z-scores from birth to discharge. The study period was divided into 2005-8, 2009-11, 2012-14 and 2015-17.

RESULTS

Weight gain, linear growth and head growth were slightly higher in 2015-2017 than in 2005-2008: 12.2 ± 2.6 to 13.1 ± 2.5 g/kg/day, 0.98 ± 0.6 to 1.03 ± 0.6 cm/week and 0.76 ± 0.2 to 0.77 ± 0.3 cm/week, respectively. It was associated with a decreased fall in weigh, length and head circumference z-scores from birth to discharge (-1.32 ± 0.9 to -1.01 ± 0.84, -1.38 ± 1.2 to -1.18 ± 1.2 and -0.41 ± 1.2 to -0.33 ± 1.3, respectively).

CONCLUSION

Postnatal growth restriction remained a common complication of prematurity despite some increment over the last years. Growth disproportionality seemed to be worsening as weight gain was increased more than linear growth.

Current practice in the introduction of solid foods for preterm infants

OBJECTIVE

The present study compared the age of first solid foods in a cohort of preterm infants with term infants and identified factors influencing timing of solid food introduction.

DESIGN

Structured interviews on infant feeding practices, growth and medical status at term equivalence and at 3, 6, 9 and 12 months corrected postnatal age. The age of solid food introduction was compared between term and preterm infants, and the influence of maternal, infant and milk feeding factors was assessed.

SETTING

This prospective longitudinal study recruited primary carers of preterm and term infants from a regional metropolitan referral hospital in eastern Australia.

PARTICIPANTS

One hundred and fifty infants (preterm, n 85; term, n 65).

RESULTS

When corrected for prematurity, preterm infants received solid foods before the recommended age for the introduction of solid foods for term infants. Median introduction of solid foods for preterm infants was 14 weeks corrected age (range 12-17 weeks). This was significantly less than 19 weeks (range 17-21 weeks) for term infants (P < 0·001). Lower maternal education and male gender were associated with earlier introduction of solid foods among preterm infants.

CONCLUSIONS

Preterm infants are introduced to solid foods earlier than recommended for term infants, taking account of their corrected age. Further research is needed to assess any risk or benefit associated with this pattern and thus to develop clear evidence-based feeding guidelines for preterm infants.

Adjustable feedings plus accurate serial length measurements decrease discharge weight-length disproportion in very preterm infants: quality improvement project

BACKGROUND

Preterm very-low-birth-weight (≤1500 g) infants exhibit disproportionate weight-for-length growth in the Neonatal Intensive Care Unit.

LOCAL PROBLEM

High frequency of body mass index (BMI) > 90th centile at discharge and 1-year postnatal age associated with elevated blood pressure and serum leptin in infancy and adolescence.

METHODS

Single-institution quality improvement project in appropriately grown infants born at 23^0/7-28^6/7 weeks gestational age and discharged home.

INTERVENTION

Adjustable feeding protocol based on valid serial length measurements (board or caliper).

RESULTS

The average monthly percentage of weight-for-length disproportion at discharge decreased from 13% in Epoch 1 to 0% in Epoch 2 (P < 0.05). Although the average Z-score for BMI at discharge was lower in Epoch 2 versus Epoch 1 (P < 0.01), this was absent by 1 year follow-up (P = 0.91).

CONCLUSIONS

Adjustable feedings plus use of accurate serial length measurements decreases weight-for-length disproportion at hospital discharge but not at 1 year.

Risk of hypertension following perinatal adversity: IUGR and prematurity

Consistent with the paradigm shifting observations of David Barker and colleagues that revealed a powerful relationship between decreased weight through 2 years of age and adult disease, intrauterine growth restriction (IUGR) and preterm birth are independent risk factors for the development of subsequent hypertension. Animal models have been indispensable in defining the mechanisms responsible for these associations and the potential targets for therapeutic intervention. Among the modifiable risk factors, micronutrient deficiency, physical immobility, exaggerated stress hormone exposure and deficient trophic hormone production are leading candidates for targeted therapies. With the strong inverse relationship seen between gestational age at delivery and the risk of hypertension in adulthood trumping all other major cardiovascular risk factors, improvements in neonatal care are required. Unfortunately, therapeutic breakthroughs have not kept pace with rapidly improving perinatal survival, and groundbreaking bench-to-bedside studies are urgently needed to mitigate and ultimately prevent the tsunami of prematurity-related adult cardiovascular disease that may be on the horizon. This review highlights our current understanding of the developmental origins of hypertension and draws attention to the importance of increasing the availability of lactation consultants, nutritionists, pharmacists and physical therapists as critical allies in the battle that IUGR or premature infants are waging not just for survival but also for their future cardiometabolic health.

Disrupted Maturation of the Microbiota and Metabolome among Extremely Preterm Infants with Postnatal Growth Failure

Growth failure during infancy is a major global problem that has adverse effects on long-term health and neurodevelopment. Preterm infants are disproportionately affected by growth failure and its effects. Herein we found that extremely preterm infants with postnatal growth failure have disrupted maturation of the intestinal microbiota, characterized by persistently low diversity, dominance of pathogenic bacteria within the Enterobacteriaceae family, and a paucity of strictly anaerobic taxa including Veillonella relative to infants with appropriate postnatal growth. Metabolomic profiling of infants with growth failure demonstrated elevated serum acylcarnitines, fatty acids, and other byproducts of lipolysis and fatty acid oxidation. Machine learning algorithms for normal maturation of the microbiota and metabolome among infants with appropriate growth revealed a pattern of delayed maturation of the microbiota and metabolome among infants with growth failure. Collectively, we identified novel microbial and metabolic features of growth failure in preterm infants and potentially modifiable targets for intervention.

Origins of neonatal leptin deficiency in preterm infants

BACKGROUND

Cord blood leptin increases with advancing gestation. Preterm delivery leads to premature separation from the maternal and placental leptin source predisposing infants to postnatal leptin deficiency, but this has not been fully described.

METHOD

Blood leptin levels were measured for infants born before 33 weeks gestation daily for the first 2 days, then weekly until 36 weeks postmenstrual age (PMA). Cord blood was obtained to provide gestational age (GA)-specific standards.

RESULTS

Cord blood leptin levels were positively associated with GA at birth, maternal body mass index (BMI) and pregnancy weight gain (all P < 0.05). Following birth, infant leptin levels decreased rapidly (74% decrease within 48 h). The extent of this decline correlated with GA (P < 0.05). Postnatal leptin began to increase by 33-36 weeks PMA, but remained below cord blood leptin levels (P < 0.01). At 36 weeks PMA, leptin levels were influenced by infant's weight and sex (P < 0.01), with females having higher leptin levels (1213 pg/ml vs. 984, P < 0.05).

CONCLUSION

Cord blood leptin is influenced by maternal weight gain and BMI, suggesting an important role for trans-placental leptin delivery. Preterm delivery leads to sustained leptin deficiency through 36 weeks PMA, with the most premature male infants facing the longest and harshest deficiency.

Early postnatal growth failure in preterm infants is not inevitable

BACKGROUND

Previously published data have demonstrated that preterm infants experience a fall across marked centile lines for weight in early life with early poor head growth also reported. This study describes a single neonatal unit's experience of longitudinal change in weight, head circumference (HC) and length in a cohort of preterm infants born <32 weeks' gestation.

METHODS

Data were collected from a single neonatal unit between July 2012 and June 2017. This period followed the introduction of improved nutritional guidelines. Patients were grouped according to their gestational age at birth. Growth lines were constructed for weight, HC and length in each gestational age group from the median measures and compared with reference centile lines.

RESULTS

Data were analysed from 396 patients consisting of 2808, 1991 and 2004 measures for weight, HC and length, respectively. Longitudinal growth plots did not show an initial absolute weight loss in any of the subgroups. Across all groups, the mean change in SD score between birth and 36 weeks was -0.27 (95% CI -0.39 to -0.15).

CONCLUSIONS

This description of longitudinal growth in a cohort of preterm infants demonstrates that early postnatal growth failure is not inevitable, with most infants growing along a trajectory close to their birth centile. There is no evidence of a 2 marked centile line weight decrease or weight loss. These data provide evidence to suggest that extrauterine weight gain tracking centile lines can be achieved.

Does type of feeding affect body composition in very low birth weight infants? - A prospective cohort study

BACKGROUND

The aim of the study was to analyse body composition of preterm infants fed with either breast milk or formula compared to a control group of full-term newborns.

METHODS

Fifty-three newborns were enrolled: a group of 34 very low birth weight (VLBW) preterm newborns subdivided into a formula-fed (n = 23; group A) and breast milk-fed (n = 11; group B) group, and a control group of 19 full-term infants (group C). Their body composition was assessed by a bioelectrical impedance analysis (BIA) either at the estimated time of birth in the VLBW group or during the 1st week of life in the full-term group.

RESULTS

There was no difference in body weight or length between any of the three studied groups. However, we discovered that fat free mass (% FFM) was lower (83.5% vs. 85.5%; p < 0.01), while fat mass (% FM) was higher (16.4% vs.14.5%; p < 0.01) in group A compared to full-term newborns. There were no such differences in FFM (84.3% vs. 85.5%; p = 0.13) or FM (15.7% vs. 14.5%; p = 0.13) between group B and control.

CONCLUSION

To sum up, the VLBW infants fed with breast milk shared similar body composition with the full-term infants, while the formula-fed VLBW developed higher amounts of adipose tissue and lower amounts of fat-free mass. This is the first study to expose differences in fat tissue content attributed to type of provided nutrition, which has become significant as early as estimated time of birth despite the comparable weight.

Effect of Nutritional Intake on the Body Composition of HIV-Exposed and HIV-Unexposed Preterm and Low Birth Weight Infants

BACKGROUND

Human breast milk (HBM) is considered inadequate in meeting protein requirements, especially for very low birth weight (VLBW) infants, which could affect body composition.

OBJECTIVES

The primary objective was to determine the effect of HBM on body composition of HIV-exposed and unexposed preterm VLBW and extremely low birth weight infants. The secondary objectives were to ascertain the effect breast milk fortification and days nil per os (NPO) have on body composition.

MATERIALS AND METHODS

A descriptive cross-sectional study was conducted. Preterm infants with a birth weight of ≤1,200 g were included. Infant nutritional intakes and body composition measurements were recorded during the 28-day follow-up period.

RESULTS

One hundred ten of 113 preterm infants received HBM and 91 infants received fortified HBM. HIV-exposed and unexposed infants receiving fortified HBM displayed differences in fat mass percentage (FM%) (0.88% versus 1.36%, p = 0.01; 0.97% versus 1.49%, p = 0.03) and fat-free mass percentage (FFM%) (98.98% versus 98.68%, p = 0.03; 99.02% versus 98.49%, p = 0.02) on days 21 and 28, respectively. Infants kept NPO displayed differences in FM% on days 7, 21, and 28 (0.9% versus 1.3%, p = 0.03; 0.99% versus 1.4%, p = 0.02; and 0.9% versus 1.6%, p = 0.0004) as well as differences in FFM% (99.1% versus 98.4%; p = 0.0005) on day 28 of life.

CONCLUSION

There were no significant differences in the body composition of infants who received HBM versus fortified HBM. However, significant differences in body composition were reported between HIV exposure groups for infants who received fortified HBM. Infants who were kept NPO were generally smaller, shorter, and had lower FM% and more FFM%.

Factors affecting body composition in preterm infants: Assessment techniques and nutritional interventions

Limited research has been conducted that elucidates the growth and body composition of preterm infants. It is known that these infants do not necessarily achieve extra-utero growth rates and body composition similar to those of their term counterparts. Preterm infants, who have difficulty in achieving these growth rates, could suffer from growth failure. These infants display an increased intra-abdominal adiposity and abnormal body composition when they achieve catch-up growth. These factors affect the quality of weight gain, as these infants are not only shorter and lighter than term infants, they also have more fat mass (FM) and less fat-free mass (FFM), resulting in a higher total fat percentage. This could cause metabolic syndrome and cardiovascular problems to develop later in a preterm infant's life. The methods used to determine body composition in preterm infants should be simple, quick, non-invasive and inexpensive. Available literature was reviewed and the Dauncey anthropometric model, which includes skinfold thickness at two primary sites and nine body dimensions, is considered in this review the best method to accurately determine body composition in preterm infants, especially in resource-poor countries. It is imperative to accurately assess the quality of growth and body composition of this fragile population in order to determine whether currently prescribed nutritional interventions are beneficial to the overall nutritional status and quality of life-in the short- and long-term-of the preterm infant, and to enable timely implementation of appropriate interventions, if required.

Fat trajectory after birth in very preterm infants mimics healthy term infants

BACKGROUND

Infants born very preterm experience poor postnatal growth relative to intrauterine growth, but at term equivalent age, they have increased percentage body fat compared with infants born at term.

OBJECTIVES

The aim of this study was to assess body composition in very preterm infants born before 32 weeks postmenstrual age and to compare this with infants born at 32-36 weeks of gestation.

METHODS

Percentage fat, fat mass and fat-free mass were measured in 87 very preterm infants born <32 weeks of gestation and studied at 32-36 weeks and in 88 control infants born at 32-36 weeks of gestation and measured on days 2-5 postnatally.

RESULTS

At 32-36 weeks, very preterm infants were lighter and shorter, had significantly greater percentage fat and absolute fat mass and had a significantly lower absolute fat-free mass than the control group. The trajectory in percentage fat over increasing postnatal age in very preterm infants was closely aligned to that in term infants.

CONCLUSIONS

Infants born very preterm accumulate fat rapidly after birth and have a deficit in fat-free mass. Fat accumulation may be triggered by birth or associated events. If this rapid fat accretion is not taken into account, assessment of growth based on weight alone will underestimate the deficit in fat-free mass.

Body composition and cognition in preschool-age children with congenital gastrointestinal anomalies

BACKGROUND

Children with congenital gastrointestinal anomalies (CGIAs) experience multiple stressors while hospitalized in neonatal intensive care units during an essential time of growth and development. Early stress and inadequate nutrition are linked to altered growth patterns and later neurodevelopmental delays. In other at-risk populations, improved fat-free mass (FFM) accretion is associated with improved cognitive outcomes.

OBJECTIVE

To determine if body composition is associated with cognitive function in preschool-age children with CGIAs.

STUDY DESIGN

An observational study examined body composition and cognition in 34 preschool-age children with CGIAs. Anthropometric measurements and body composition testing via air displacement plethysmography were obtained. Measurements were compared with a reference group of healthy, term-born children. Cognition was measured with the NIH Toolbox Early Childhood Cognition Battery. Linear regression was used to test the association of body composition with cognitive function.

RESULTS

Compared with the reference group, children with CGIAs had similar anthropometric measurements (weight, height, and body mass index z-scores) and body composition at preschool-age. Processing speed scores were lower than standardized means (p = 0.001). Increased FFM was associated with higher receptive vocabulary scores (p = 0.001), cognitive flexibility scores (p = 0.005), and general cognitive function scores (p = 0.05).

CONCLUSIONS

At preschool-age, children with CGIAs have similar growth and body composition to their peers. In children with CGIAs, higher FFM was associated with higher cognitive scores. Closer tracking of body composition and interventions aimed at increasing FFM may improve long-term outcomes in this population.

Measuring body composition in the preterm infant: Evidence base and practicalities

Preterm birth and body composition have demonstrable effects on growth and later health outcomes. Preterm infants reach term equivalent age with a lower proportion of lean mass and higher body fat percentage than their term equivalent counterparts. Weight and length do not give an accurate assessment of body composition. Tracking body composition rather than just weight is a fundamental part of improving nutritional outcomes. This is important given the ongoing controversies regarding the nutritional needs of preterm infants, as well as establishing suitable targets for their growth. In this review we describe current methodologies used in the measurement of body composition of the preterm infant and the review the recent published evidence for their accuracy and utility. Current measurement techniques employed include air displacement plethysmography, bioelectrical impedance analysis, isotope dilution techniques, MRI and a combination of manual measurements including skinfold thickness, body mass index and mid upper arm/mid-thigh circumference. These measures allow for the estimation of fat mass, fat-free mass and regional assessment of adiposity. Some methods, such as dual-energy X-ray absorptiometry and air displacement plethysmography do allow for comparison of change in body composition over time in cohorts of preterm infants that may be studied over a longer period of time and into adult life. However, none of the currently described methods give an accurate and practically achievable method of obtaining body composition measures in preterm infants in day to day routine clinical practise, although this remains a key priority when decisions are being made about how best to feed.

Human milk protein vs. formula protein and their use in preterm infants

PURPOSE OF REVIEW

We review the current available evidence on the metabolic fate of human milk proteins and their potential clinical implications for growth and body composition development vs. those of formula proteins in preterm infants.

RECENT FINDINGS

The decreased content of human milk protein in preterm mothers throughout lactation might contribute to the reduced growth reported in exclusively human milk-fed infants compared with that of formula-fed infants. Recent studies have demonstrated that preterm infants are capable of degrading human milk proteins regardless of their degree of prematurity or postnatal age, with limited contribution from milk proteases to protein digestion. The nitrogen balance of fortified human milk-fed preterm infants is higher than that of formula-fed preterm infants. Moreover, the growth of human milk-fed preterm infants appears to be accompanied by fat-free mass deposition.

SUMMARY

Provided that adequate protein and energy intakes are delivered, human milk enhances protein use rather than oxidation as well as promotes tissue growth, leading to preferential fat-free mass deposition and contributing to the recovery of the body composition in preterm infants. Human milk feeding should be supported and promoted for all preterm mother-infant pairs.

Preterm human milk macronutrient concentration is independent of gestational age at birth

OBJECTIVE

To evaluate the amount of macronutrients in aggregate of human milk samples after preterm delivery during the first 2 months of lactation.

METHODS

Analysis of the donated single milk samples, gained by complete emptying of the whole breast at the same daytime between 24+0 and 35+6 gestational age (GA), was designed as prospective observational cohort trial. Two milk samples were analysed every postnatal week up to the discharge from the hospital, week 9 or loss of lactation. 24-Hour milk collection was not done. Analysis was performed using the MIRIS Human Milk Analyser (MIRIS AB, Uppsala, Sweden).

RESULTS

A set of 1917 human milk samples donated by 225 mothers after preterm labour was analysed. Group A (24-30 GA) contains 969 milk samples; group B (31-35 GA) contains 948 milk samples. No difference in milk composition between the groups was identified. Median of true protein content decreased from 1.6 g/dL in group A and 1.5 g/dL in group B in the first week of life, to 1.1 g/dL in both groups at the end of week 3, and then remained stable up to week 9. Content of carbohydrates and fat was stable during the whole observation, with interindividual differences.

CONCLUSION

Human milk does not differ as a function of degree of prematurity. Protein content of preterm human milk is low and decreases during the first 3 weeks of lactation. Recommended daily protein intake cannot be achieved with routine fortification in majority of milk samples.

Comparison of physical activity and body composition in a cohort of children born extremely preterm or with extremely low birth weight to matched term-born controls: a follow-up study

OBJECTIVES

To compare physical activity and body composition in a cohort of children born extremely preterm/extremely low birth weight (EP/ELBW) with term-born (TB) controls.

METHODS

A regional cohort of children born during 1999-2000 at gestational age <28 weeks or with birth weight <1000 g and their individually matched TB controls were examined in 2010-2011. Information on physical activity was obtained from parental questionnaires, and body composition was determined by anthropometry and dual X-ray absorptiometry.

RESULTS

Fifty-seven EP/ELBW and 57 TB controls were included at a mean age of 11.6 years. Compared with the TB children, the EP/ELBW-born children exercised less often (22% vs 44% exercised more than 3 days per week), had lower physical endurance and poorer proficiency in sports and play and were less vigorous during exercise (p<0.05). They also had lower values (mean; 95 % CI) for muscle mass (0.9; 0.3-1.5 kg), total bone mineral density z-score (0.30; 0.13-0.52 units) and fat mass ratio (0.14; 0.06-0.21 units). The association between physical activity and bone mineral and skeletal muscle mass accrual was significantly weaker for the EP/ELBW-born than the TB children.

CONCLUSIONS

The EP/ELBW-born children were less physically active, had signs of an unfavourable body composition with less muscle mass and lower bone mineral density than the TB controls. The association between physical activity and the measures of body composition was weaker in the group of EP/ELBW-born children.

Neurodevelopmental outcomes following necrotizing enterocolitis

Necrotizing enterocolitis (NEC), a gastrointestinal emergency predominantly affecting premature infants, is associated with increased risk for poor neurodevelopmental outcomes. NEC often strikes during a period of rapid and dynamic neurologic development when the brain is particularly vulnerable to insults and nutrient deficits. The pathogenesis of neurodevelopmental impairment following NEC is likely multifactorial, with both nutritional and non-nutritional factors at play. Follow-up testing that ensures early detection and intervention for impairments is crucial to optimize neurodevelopmental outcomes following NEC. A multifaceted approach to follow-up after NEC is necessary, with close monitoring of growth, serial developmental assessments, neurologic examinations, hearing and vision testing and neuroimaging. Further research is needed to understand the pathogenesis of neurodevelopmental impairment following NEC, to identify more targeted follow-up tests, and to discover interventions aimed at optimizing neurodevelopmental outcomes following NEC.

Early body composition changes are associated with neurodevelopmental and metabolic outcomes at 4 years of age in very preterm infants

BACKGROUND

Very preterm (VPT) infants are at-risk for altered growth, slower speed of processing (SOP), and hypertension. This study assesses the relationship between postnatal body composition (BC), neurodevelopment (indexed by SOP), and blood pressure (BP) in VPT infants.

METHODS

Thirty-four VPT infants underwent weekly measurements and BC testing until discharge and post-discharge at 4 mos CGA and 4 yrs. At post-discharge visits, SOP was assessed using visual evoked potentials and the NIH Toolbox; BP was also measured.

RESULTS

In-hospital rate of weight, length and fat-free mass (FFM) gains were associated with faster SOP at 4 yrs. Higher rate of gains in weight and FFM from discharge to 4 mos CGA were associated with faster SOP at 4 mos CGA, while higher fat mass (FM) gains during the same time were positively associated with BP at 4 yrs. BC at 4 yrs nor gains beyond 4 mos CGA were associated with outcomes.

CONCLUSIONS

In VPT infants, early FFM gains are associated with faster SOP, whereas post-discharge FM gains are associated with higher BPs at 4 yrs. This shows birth to 4 mos CGA is a sensitive period for growth and its relation to neurodevelopmental and metabolic outcomes. Close monitoring and early nutritional adjustments to optimize quality of gains may improve outcomes.

Evaluation of irisin and visfatin levels in very low birth weight preterm newborns compared to full term newborns-A prospective cohort study

Premature infants represent one of the groups with increased risk for metabolic syndrome. Our study is the first one to evaluate irisin and visfatin levels, associated with the metabolic syndrome, both in blood of preterm and full-term infants, as well as in the breastmilk of their mothers. A total of 72 newborns was enrolled in the study, including 53 very low birth weight preterm infants and a control group of 19 term infants. The levels of irisin and visfatin were determined by a commercial enzyme-linked immunoabsorbent assay both in the baby serum and maternal milk twice, first during the 1^st week of life and then 4 weeks later. Preterm infants had significantly lower serum irisin levels compared to the term infants. Overall, serum irisin level during the 1^st week of life was positively correlated with several anthropometric measurements at birth, as well as during 5^th weeks of age. In contrast, serum visfatin levels during 5^th week of life were negatively correlated with z-scores of birth weight, weight and head circumference during 5^th week of age. We found a strong negative correlation between serum irisin and serum visfatin levels at both analyzed time points. The level of milk visfatin was significantly higher in the mothers of the preterm group during 5^th week of life. In conclusion, our results provide further evidence that irisin and visfatin may play physiologic roles in development of both preterm and full-term newborns during their first month after birth. Observed differences in irisin and visfatin serum and breastmilk concentrations during the earliest stages of life may contribute to development of catch up growth, but also, they might eventually lead to a higher risk for metabolic syndrome in prematurely born children in later years.

Body composition in preterm infants with intrauterine growth restriction: a cohort study

Aims:

The comparison of body composition parameters between the small for gestational age (SGA) and appropriate for gestational age (AGA) at term, 1, 3 and 5 months corrected ages in very preterm infants.

Methods:

This cohort study included 92 preterm infants at term age, younger than 32 weeks or <1500 g, classified in two groups: SGA and AGA. Anthropometry and body composition, estimated by air displacement plethysmography, were evaluated at the corrected ages: term and 1, 3, and 5 months. We used the lean mass/fat mass index (LM/FM) at each time point and the weight, length and head circumference SDS gain between the time points.

Results:

At term age, the SGA preterm infants had less lean mass (g), fat mass (g) and percent fat mass but a greater LM/FM index than AGA infants (P<0.001). At 1 month corrected age the LM/FM index and percent fat mass between the groups became similar. Lower lean mass persisted up to 3 months in the SGA group [4004 g (3256–4595) vs. 4432 g (3190–6246), P<0.001]. During the first month corrected age, the weight SDS gain was higher in SGA preterm infants when compared to AGA preterm infants. However, the SGA preterm infants remained lighter, shorter and with smaller head circumferences than the AGA preterm infants until 3 months of corrected age.

Conclusions:

The greater lean tissue deficits and an earlier “catch-up” in fat in the SGA group can reflect growth patterns variability since the early life.

Effect of foetal and infant growth and body composition on respiratory outcomes in preterm-born children

Body composition and growth outcomes of preterm-born subjects have been studied by many researchers. In general, preterm-born children have lower height and weight especially in infancy. Despite showing potential for catch-up growth, they continue to lag behind their term counterparts in adolescence and adulthood. The various methods of studying body composition and the differing gestations and ages at which it is assessed may go some way to explaining the inconsistent results observed in different studies. In addition, there is a paucity of data on the effects of foetal and infant growth and of body composition on later respiratory outcomes. In largely term-born subjects, foetal growth and growth trajectories appear to have differential effects on later respiratory outcomes. Early weight gain in infancy appears to be associated with increased respiratory symptoms in childhood but catch-up growth in infancy appears to be associated with possible improved lung function status.

Postdischarge Feeding of Very-low-birth-weight Infants: Adherence to Nutrition Guidelines

OBJECTIVES

Infant feeding guidelines are important public health strategies to promote optimal growth, development, and chronic disease prevention, but their effectiveness is contingent upon families' ability to adhere to them. Little is known of adherence to guidelines among nutritionally vulnerable infants, specifically those born very-low-birth-weight (VLBW) (<1500 g). This study investigated whether postdischarge feeding practices for VLBW infants align with current recommendations and explored parental and infant baseline sociodemographics related to these practices.

METHODS

Prospectively collected data from families of 300 VLBW infants participating in a randomized clinical trial (ISRCTN35317141) were used. Baseline demographics were obtained at enrollment and postdischarge feeding practices via monthly telephone questionnaires to 6 months corrected age (CA).

RESULTS

At discharge, 4 and 6 months CA, 72%, 39%, and 29% of infants received any amount of mother's milk, respectively; exclusive breast-feeding rates were 49%, 20%, and 6%, respectively. Among infants receiving mother's milk, rates of vitamin D supplementation were ≥83%. Recommendations for introducing solids between 4 and 6 months CA were followed by 71% of the cohort and for iron supplementation by 58%. Overall, 12% of infants adhered to all aforementioned recommendations. Mothers with university degrees were more likely to provide mother's milk, whereas mothers of Middle Eastern/South Asian ethnicity were less likely to provide mother's milk.

CONCLUSIONS

Low rates of partial and exclusive breast-feeding of VLBW infants to 6 months CA were reported. Overall adherence to iron supplementation was low. Strategies to provide increased support for mothers identified as at-risk should be developed.

The effect of maternal HIV status and treatment duration on body composition of HIV-exposed and HIV-unexposed preterm, very and extremely low-birthweight infants

BACKGROUND

There is an evidence gap regarding the relationship between HIV exposure, body composition (and the quality thereof) and preterm infants.

AIM

This study determined the body composition of HIV-exposed, preterm very low-birthweight (VLBW) and extremely low-birthweight (ELBW) infants and to assess the effect of maternal HAART duration on the body composition of this vulnerable population.

METHODS

A descriptive cross-sectional study was conducted. HIV-exposed and -unexposed preterm infants (<37 weeks) with a birthweight of ≤1200g were included. Maternal medical background was recorded. Infant body composition measurements were recorded weekly during the 28-day follow-up period.

RESULTS

Thirty preterm infants (27%) were HIV-exposed. HIV-exposed infants had significantly (=0.01) lower gestational ages than HIV-unexposed infants (25-28 weeks). HIV-exposed infants had significantly lower measurements on day 21 and day 28 for triceps skinfold (TSF) (2.5 mm vs 2.7 mm, = 0.02 and 2.6 mm vs 2.9 mm, <0.01), subscapular skinfold (SSSF) (2.3 mm vs 2.6 mm, = 0.02 and 2.4 mm vs 2.7 mm, =<0.01) and fat mass percentage (FM%) (0.9% vs 1.4%, = 0.02 and 1.0% vs 1.5%, = 0.03). HIV-exposed infants whose mothers received HAART for ≥ 20 weeks were heavier and had a higher FM% and lower fat-free mass percentage (FFM%) at birth than HIV-exposed preterm infants whose mothers received highly active antiretroviral therapy for ≥ 4- < 20 weeks.

CONCLUSION

Mothers receiving HAART could have increased risk of preterm delivery, and the duration of maternal HAART affects postnatal body composition of their infants. Body composition differs between HIV-exposed and HIV-unexposed preterm infants.

The DIAMOND trial - DIfferent Approaches to MOderate & late preterm Nutrition: Determinants of feed tolerance, body composition and development: protocol of a randomised trial

BACKGROUND

Babies born at moderate-late preterm gestations account for > 80% of all preterm births. Although survival is excellent, these babies are at increased risk of adverse neurodevelopmental outcomes. They also are at increased risk of adverse long-term health outcomes, such as cardiovascular disease, obesity and diabetes. There is little evidence guiding optimal nutritional practices in these babies; practice, therefore, varies widely. This factorial design clinical trial will address the role of parenteral nutrition, milk supplementation and exposure of the preterm infant to taste and smell with each feed on time to tolerance of full feeds, adiposity, and neurodevelopment at 2 years.

METHODS/DESIGN

The DIAMOND trial is a multi-centre, factorial, randomised, controlled clinical trial. A total of 528 babies born between 32+ 0 and 35+ 6 weeks' gestation receiving intravenous fluids and whose mothers intend to breastfeed will be randomised to one of eight treatment conditions that include a combination of each of the three interventions: (i) intravenous amino acid solution vs. intravenous dextrose solution until full milk feeds established; (ii) milk supplement vs. exclusive breastmilk, and (iii) taste/smell given or not given before gastric tube feeds. Babies will be excluded if a particular mode of nutrition is clinically indicated or there is a congenital abnormality. Primary study outcome: For parenteral nutrition and milk supplement interventions, body composition at 4 months' corrected age. For taste/smell intervention, time to full enteral feeds defined as 150 ml.kg- 1.day- 1 or exclusive breastfeeding.

SECONDARY OUTCOMES

Days to full sucking feeds; days in hospital; body composition at discharge; growth to 2 years' corrected age; development at 2 years' corrected age; breastfeeding rates.

DISCUSSION

This trial will provide the first direct evidence to inform feeding practices in moderate- to late-preterm infants that will optimise their growth, metabolic and developmental outcomes.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry - ACTRN12616001199404 . This trial is endorsed by the IMPACT clinical trials network ( https://impact.psanz.com.au ).

Leptin and IGF-1 in relation to body composition and bone mineralization of preterm-born children from infancy to 8 years

OBJECTIVE

Preterm birth has been associated with altered body composition, especially increased fat mass (FM) and decreased bone mineralization, and leptin and IGF-1 have been suggested to be involved in the regulation of both. We aimed to study the interplay between leptin, IGF-1, FM and bone mineralization measured in infancy and childhood of children born preterm.

DESIGN

Observational study.

PATIENTS/SUBJECTS

Seventy-nine (40 boys) preterm-born children (gestational age ≤32 weeks and/or birth weight ≤1500 g) aged 8 years.

MEASUREMENTS

Serum leptin and IGF-1 were measured at term age, at 3- and 6-month corrected age (CA), and 8 years. Body composition (fat and lean mass) and bone parameters (bone area, mineral content and density) were measured by Dual-energy X-ray Absorptiometry (DXA) at term age, 6-month CA and 8 years.

RESULTS

Leptin was positively associated with FM at all time points and with bone parameters at term age and 6-month CA. IGF-1 was associated with body composition and bone density at most of the time points. Explained variation in bone mineralization increased significantly by adding bone area (BA) and height to the models.

CONCLUSIONS

During infancy and childhood, leptin and IGF-1 were associated with body composition in preterm-born children. In addition, leptin was associated with bone parameters in early infancy, but not in childhood. It is hypothesized that a complicated interplay between multiple pathways, which most likely changes over time, is involved in regulation of body composition and bone mineralization of preterm-born infants.

The Timing of Initiating Complementary Feeding in Preterm Infants and Its Effect on Overweight: A Systematic Review

BACKGROUND

What is the appropriate time to start complementary feeding for preterm infants? The answer to this question is yet under debate. The timing of initiating complementary feeding may be associated with overweight in term infants. This systematic review aimed to study the effect of the timing of initiating complementary feeding on overweight in preterm infants. Predefined search items included preterm infants, complementary feeding, overweight, and their synonyms.

SUMMARY

The search identified 15,749 articles, of which 5 articles were included. Three studies presented data of randomized controlled trials and 2 studies were cohort studies. Two randomized controlled trials found no significant difference in body mass index (BMI) Z-score between the intervention groups at 12 months of age. One randomized controlled trial presented a significant greater mean rate of growth in length per week until 12 months in the preterm weaning strategy-group compared with the current best practices. One observational study concluded that each month the infants received complementary food later, the Z-score for length and weight was reduced by 0.1. Key Messages: No clear conclusion could be drawn from the included studies. This review illustrates the need for further research to access the effect of the timing of initiating complementary feeding on overweight in preterm infants.

Parenteral nutrition for preterm infants: Issues and strategy

Due to transient gut immaturity, most very preterm infants receive parenteral nutrition (PN) in the first few weeks of life. Yet providing enough protein and energy to sustain optimal growth in such infants remains a challenge. Extrauterine growth restriction is frequently observed in very preterm infants at the time of discharge from hospital, and has been found to be associated with later impaired neurodevelopment. A few recent randomized trials suggest that intensified PN can improve early growth; whether or not such early PN improves long-term neurological outcome is still unclear. Several other questions regarding what is optimal PN for very preterm infants remain unanswered. Amino acid mixtures designed for infants contain large amounts of branched-chain amino acids and taurine, but there is no consensus on the need for some nonessential amino acids such as glutamine, arginine, and cysteine. Whether excess growth in the first few weeks of life, at a time when very preterm infants receive PN, has an imprinting effect, increasing the risk of metabolic or vascular disease at adulthood continues to be debated. Even though uncertainty remains regarding the long-term effect of early PN, it appears reasonable to propose intensified initial PN. The aim of the current position paper is to review the evidence supporting such a strategy with regards to the early phase of nutrition, which is mainly covered by parenteral nutrition. More randomized trials are, however, needed to further support this type of approach and to demonstrate that this strategy improves short- and long-term outcome.

The Energy Costs of Prematurity and the Neonatal Intensive Care Unit (NICU) Experience

Premature neonates are in an energy deficient state due to (1) oxygen desaturation and hypoxia events, (2) painful and stressful stimuli, (3) illness, and (4) neurodevelopmental energy requirements. Failure to correct energy deficiency in premature infants may lead to adverse effects such as neurodevelopmental delay and negative long-term metabolic and cardiovascular outcomes. The effects of energy dysregulation and the challenges that clinicians in the Neonatal Intensive Care Unit (NICU) face in meeting the premature infant's metabolic demands are discussed. Specifically, the focus is on the effects of pain and stress on energy homeostasis. Energy deficiency is a complex problem and requires a multi-faceted solution to promote optimum development of premature infants.

Can Basic Characteristics Estimate Body Composition in Early Infancy?

OBJECTIVES

Increasing evidence demonstrates that body composition in early life contributes to the programming of health later in life in both full-term and preterm infants. Given the important role of body composition, the increased availability of easy, noninvasive, and accurate techniques for its assessment has been recommended. The aim of the present study was to identify basic characteristics and anthropometric measurements that best correlate with body composition in infants.

METHODS

Anthropometric measurements and body composition assessed by air-displacement plethysmography were assessed either at birth or at term-corrected age in 1239 infants (654 full-term, 585 preterm). The associations of sex, GA (gestational age), and weight with FFM (fat-free mass) and FM (fat mass) adjusted by length (g/cm) were investigated by multiple linear regression models. Bland-Altman tests were performed, and an equation for calculating FFM was determined.

RESULTS

Preterm infants exhibited increased FM and reduced FFM compared with full-term infants (477.6 ± 204 vs 259.7 ± 147 g and 2583 ± 494 vs 2770 ± 364 g, respectively). GA, male sex, and weight were positively associated with FFM (r = 0.806, P < 0.0001; 6.1 g of average bias). GA and male sex were negatively associated with FM, whereas weight was positively associated with FM (r = 0.641, P < 0.0001; 4.9 g of average bias).

CONCLUSIONS

The assessment of body composition represents the criterion standard. When body composition assessment is not feasible, the equation based on sex, GA, and anthropometric measurements can be useful in predicting body composition in both full-term and preterm infants.

High-resolution rapid neonatal whole-body composition using 3.0 Tesla chemical shift magnetic resonance imaging

BackgroundTo evaluate a whole-body rapid imaging technique to calculate neonatal lean body mass and percentage adiposity using 3.0 Tesla chemical shift magnetic resonance imaging (MRI).MethodsA 2-Point Dixon MRI technique was used to calculate whole-body fat and water images in term (n=10) and preterm (n=15) infants.ResultsChemical shift images were obtained in 42 s. MRI calculated whole-body mass correlated closely with measured body weight (R²=0.87; P<0.001). Scan-rescan analysis demonstrated a 95% limit of agreement of 1.3% adiposity. Preterm infants were born at a median of 25.7 weeks' gestation with birth weight 840 g. At term-corrected age, former preterm infants were lighter than term-born controls, 2,519 vs. 3,094 g regressing out age and group as covariates (P=0.005). However, this was not because of reduced percentage adiposity 26% vs. 24% (P=0.28). At term-corrected age, former preterm infants had significantly reduced lean body mass compared with that of term-born controls 1,935 vs. 2,416 g (P=0.002).ConclusionRapid whole-body imaging for assessment of lean body mass and adiposity in term and preterm infants is feasible, accurate, and repeatable. Deficits in whole-body mass in former preterm infants at term-corrected age are due to reductions in lean body mass not due to differences in adiposity.

Is the body composition development in premature infants associated with a distinctive nuclear magnetic resonance metabolomic profiling of urine?

OBJECTIVE

Preterm infants' body composition at term-corrected age differs from that of term infants but appears to be similar at the age of 3 months. The aim of this study was to compare the metabolomic pattern of preterm infants at term and at 3 months with that of term infants and to determine its association with body composition development.

METHOD

We designed a pilot study. Growth and body composition were evaluated by an air displacement plethysmography system in 13 preterm infants and seven term newborns at term and at 3 months of corrected age. Urine samples were collected at the same time points and analysed by nuclear magnetic resonance.

RESULTS

At term-corrected age, preterm infants showed a higher fat mass percentage compared with that of term newborns, whereas at 3 months of corrected age, the body composition parameters were similar between the groups. At the first time point, nuclear magnetic resonance analysis showed a urinary increase in choline/phosphocholine, betaine and glucose in preterm infants. At the second time point, the preterm group exhibited a urinary increase in choline/phosphocholine and a decrease in betaine.

CONCLUSIONS

The increased urinary excretion of choline, a betaine precursor, could reflect a potential altered metabolism in preterm infants.

Anthropometry and Body Composition of Preterm Neonates in the Light of Metabolic Programming

The improved survival of preterm infants has led to increased interest regarding their health as adults. In the context of metabolic programming, the connection between perinatal and early postnatal nutrition and growth with health in later life has brought to the fore the role of catch-up growth during the first months of preterm infants' lives and its association with body fat and obesity in childhood or puberty. A state-of-the art review was conducted in order to assess the way catch-up is evaluated, in terms of timing and rate. Adequate growth is of major importance for neurodevelopment; however, it may compete with adiposity or metabolic health. Studies based on body composition assessment have given conflicting results as regards the effect of early versus late and rapid versus slow catch-up growth on later health, mainly attributed to the lack of established criteria and definitions. Given that adequate early nutrition is crucial for the neurodevelopment of preterm infants, further studies are needed on the role of catch-up growth in long-term outcome, using generally accepted qualitative and quantitative criteria.

Individualized Postnatal Growth Trajectories for Preterm Infants

BACKGROUND

Growth of preterm infants is monitored using fetal charts despite individual trajectories being downshifted postnatally by adaptational processes. The study aims to compare different approaches to create individualized postnatal trajectories.

METHODS

Three approaches to achieve growth similar to healthy term infants at 42+0/7 weeks postmenstrual age (PMA) on World Health Organization growth standards (WHOGS) (target weight) were tested by comparing trajectories obtained by: 1) following birth percentiles (Birth-Weight-Percentile Approach); 2) following percentiles achieved at day of life 21 (Postnatal-Percentile Approach); 3) using day-specific fetal median growth velocities starting at day of life 21 (Fetal-Median-Growth Approach [FMGA]). The primary outcome was delta weight (ΔW), defined as difference between target weight (WHOGS) at 42+0/7 weeks and weight predicted by trajectories. The secondary outcome was ΔW vs %fat mass in a cohort of 20 disease-free surviving very low-birth-weight infants.

RESULTS

Birth-Weight-Percentile and Postnatal-Percentile Approach showed high ΔW; FMGA alone reduced ΔW. Introducing a factor to FMGA to reflect the transition to extrauterine conditions (Growth-Velocity Approach [GVA]) minimized ΔW. GVA merged with target and best normalized for body composition related to ΔW.

CONCLUSIONS

GVA provides an evidence-based approach for individualized growth trajectories. GVA is based on physiologic data and that healthy preterm infants adjust their postnatal trajectory below their birth percentile. GVA may reflect a biologic principle because it matches consistently with WHOGS at 42+0/7 weeks for all preterm infants from 24 to 34 weeks. This concept could become a bedside tool to aid clinicians in monitoring growth, guiding nutrition, and minimizing chronic adult disease risks as a consequence of unguided, inappropriate growth.