Body Composition in Very Preterm Infants: Role of Neonatal Characteristics and Nutrition in Achieving Growth Similar to Term Infants

Impact of Nutrient Intake on Body Composition in Very Low-Birth Weight Infants Following Early Progressive Enteral Feeding

Preterm infants have increased body adiposity at term-equivalent age and risk of adverse metabolic outcomes. The aim of the study was to define how nutrient intake may impact body composition (BC) of very low-birth weight infants fed with early progressive enteral feeding and standard fortification. Eighty-six infants with <1500 g birth weight were included in the BC study and stratified into extremely preterm (EP) and very preterm (VP) groups. Nutrient intake was calculated during the first 28 days and BC assessed by dual X-ray absorptiometry at discharge and by skinfold thickness at 12 months of corrected age (CA). Total nutrient intake did not differ between the groups. EP infants had a higher fat mass percentage at discharge than VP infants (24.8% vs. 19.4%, p < 0.001); lean mass did not differ. None of the nutrients had any impact on BC of EP infants. Protein intake did not result in a higher lean mass in either group; fat intake was a significant predictor of increased fat mass percentage in VP infants at discharge (p = 0.007) and body adiposity at 12 months of CA (p = 0.021). Nutritional needs may depend on gestational age and routine fortification should be used with caution in more mature infants.

Body composition in healthy singleton term infants using the three-dimensional photonic scanning method: A multicenter cross-sectional study

OBJECTIVES

Body composition is an integral part of the nutritional assessment during infancy as it is closely related to future health. The three-dimensional photonic body surface scanning (3-DPS) method is a promising new technique for measuring body composition in children because of its advantages of easy operation, low cost, and no exposure to radiation. Using 3-DPS, this study aimed to illustrate the growth trajectories of body composition indicators during infancy according to sex and age.

METHODS

This was a multicenter cross-sectional study. The body compositions of 9644 singleton term infants from four centers in Shandong Province, China, were assessed using 3-DPS. The data of 8769 healthy infants (52.0% boys), whose z scores of weight-for-length, length-for-age, and weight-for-age, according to World Health Organization standards, were in the range of -2 to 2, -3 to 3, and -3 to 3, respectively, were sampled to construct percentile curves of fat mass (FM), fat-free mass (FFM), FM percentage (FM%), FM index (FMI), and FFM index (FFMI) with the generalized additive model for location, scale, and shape method.

RESULTS

Percentile charts for FM, FFM, FM%, FMI, and FFMI were developed based on age and sex. FM and FFM presented consistent trajectories with that of weight, with the fastest growth occurring at 1 to 3 mo of age. FM%, FMI, and FFMI increased with age, peaked at 6 mo, and gradually declined, which was consistent with the body mass index trend. All indicators, except for FFMI, were always significantly higher in boys than in girls ages 1 to 12 mo, indicating that sex differences in body composition existed mainly in FM rather than in lean body mass.

CONCLUSIONS

The body composition of healthy singleton term infants during infancy varies with age; boys may have more FM accumulation than girls.

Inflammation induces stunting by lowering bone mass via GH/IGF-1 inhibition in very preterm infants

BACKGROUND

Sustained systemic inflammatory response (SIR) was associated with poor postnatal growth in very preterm infants (VPI). We hypothesize that VPI with sustained SIR will exhibit linear growth retardation related to lower bone mass accrual mediated by GH/IGF-1 axis inhibition at term corrected age (CA).

METHODS

C-reactive protein (CRP), procalcitonin (PCT), growth hormone (GH), insulin-like growth factor 1 (IGF-1), calcium, phosphorus, alkaline phosphatase, anthropometric, nutritional, neonatal and maternal data were collected prospectively in 23 infants <32 weeks gestational age. Body composition using dual-energy X-ray absorptiometry was performed at term CA. Analysis was undertaken with multiple linear regression models.

RESULTS

At term CA 11 infants with sustained SIR compared with 12 infants without sustained SIR present significantly lower IGF-1, length z-score (LZS), bone mineral content (BMC) and lean mass (LM), and higher GH and fat mass (FM). LZS was associated significantly with PCT, BMC with IGF-1, FM and LM with CRP, GH with bronchopulmonary dysplasia and CRP, and IGF-1 with invasive mechanical ventilation, CRP and PCT.

CONCLUSIONS

In addition to the known effect on linear growth failure, sustained SIR induces lower bone mass accrual related to higher GH and lower IGF-1 levels in VPI.

IMPACT

Very preterm infants (VPI) with sustained systemic inflammatory response (SIR) compared with VPI without SIR present stunting, lower bone mass, higher GH and lower IGF-1 levels at term corrected age. SIR may help to explain the influence of non-nutritional factors on growth and body composition in VPI. SIR induces postnatal stunting related to lower bone mass accrual via GH/IGF-1 axis inhibition in VPI. VPI with SIR need special attention to minimize inflammatory stress, which could result in improved postnatal growth. Research on inflammatory-endocrine interactions involved in the pathophysiology of postnatal stunting is needed as a basis for new interventional approaches.

The association between BMI trajectories and bronchopulmonary dysplasia among very preterm infants

OBJECTIVE

To investigate the association between change in body mass index (BMI) from birth to 36 weeks gestation (ΔBMI) and bronchopulmonary dysplasia (BPD) among infants born <30 weeks gestation.

METHODS

This was a multicenter retrospective cohort study (2015-2018) of infants born <30 weeks gestation and alive at ≥34 weeks corrected. Main exposure was a change in BMI z score from birth to 36 weeks corrected age grouped into quartiles of change. Association between ΔBMI z scores and BPD was assessed using generalized linear mixed models.

RESULTS

Among 772 included infants, 51% developed BPD. From birth to 36 weeks CGA, the weight z score of infants with BPD decreased less than for BPD-free infants, despite a greater decrease in length z score and similar caloric intake resulting in increases in BMI z score (median [IQR], 0.16 [-0.64; 1.03] vs -0.29 [-1.03; 0.49]; P < 0.01). In the adjusted analysis, higher ΔBMI z score quartiles were associated with higher odds of BPD (Q3 vs Q2, AOR [95% CI], 2.02 [1.23; 3.31] and Q4 vs Q2, AOR [95% CI], 2.00 [1.20; 3.34]).

CONCLUSION

Among preterm infants, an increase in BMI z score from birth to 36 weeks corrected is associated with higher odds of BPD.

IMPACT

Preterm infants with evolving lung disease often experience disproportionate growth in the neonatal period. In this multicenter cohort study, increases in BMI z score from birth to 36 weeks CGA were associated with higher odds of BPD. Despite similar caloric intake, infants with BPD had a higher weight- but lower length-for-age, resulting in higher BMI z score compared to BPD-free infants. This suggests that infants with evolving BPD may require different growth and nutritional targets compared to BPD-free infants.

Nutritional Management and Recommendation for Preterm Infants: A Narrative Review

Background: Preterm birth is defined as birth before 37 completed weeks of pregnancy. It is the most important predictor of adverse health and development infant outcomes that extend into the early childhood and beyond. It is also the leading cause of childhood mortality under 5 years of age worldwide and responsible for approximately one million neonatal deaths. It is also a significant contributor to childhood morbidities, with many survivors are facing an increased risk of lifelong disability and poor quality of life. Purpose: In this article, we aimed to describe features of preterm infants, what makes them different from term infants, and what to consider in nutritional management of preterm infants through a traditional narrative literature review. Discussion: Preterm infants are predisposed to more health complications than term infants with higher morbidity and mortality. This morbidity and mortality can be reduced through timely interventions for the mother and the preterm infant. Maternal interventions, such as health education and administration of micronutrient supplementation, are given before or during pregnancy and at delivery, whereas appropriate care for the preterm infants should be initiated immediately after birth, which include early breastfeeding and optimalization of weight gain. Conclusion: Essential care of the preterm infants and early aggressive nutrition should be provided to support rapid growth that is associated with improved neurodevelopmental outcomes. The goal is not only about survival but making sure that these preterm infants grow and develop without any residual morbidity.

Early weight gain trajectories and body composition in infancy in infants born very preterm

BACKGROUND

Concerns are raised about the influence of rapid growth on excessive fat mass (FM) gain in early life and later cardiometabolic health of infants born preterm.

OBJECTIVES

To study the association between postnatal weight gain trajectories and body composition in infancy in infants born very preterm.

METHODS

In infants born <30 weeks gestation, we evaluated associations between weight Z-score trajectories for three consecutive timeframes (NICU stay, level-II hospital stay and at home) and body composition, measured at 2 and 6 months corrected age by air-displacement plethysmography.

RESULTS

Of 120 infants included, median gestational age at birth was 27⁺⁵ (interquartile range 26⁺¹ ;28⁺⁵ ) and birth weight 1015 g (801;1250). The majority of infants did not make up for their initial loss of weight Z-score, but growth and later body composition were within term reference values. Weight gain during NICU stay was not associated with fat mass (absolute, %FM or FM index) in infancy. Weight gain during NICU and level II hospital stay was weakly associated with higher absolute lean mass (LM), but not after adjustment for length (LM index). Weight gain in the level-II hospital was positively associated with fat mass parameters at 2 months but not at 6 months. Strongest associations were found between weight gain at home and body composition (at both time points), especially fat mass.

CONCLUSIONS

Weight gain in different timeframes after preterm birth is associated with distinct parameters of body composition in infancy, with weight gain at home being most strongly related to fat mass.

Body composition and neuromotor development in the year after NICU discharge in premature infants

BACKGROUND

Hypothesis: neuromotor development correlates to body composition over the first year of life in prematurely born infants and can be influenced by enhancing motor activity.

METHODS

Forty-six female and 53 male infants [27 ± 1.8 (sd) weeks] randomized to comparison or exercise group (caregiver provided 15-20 min daily of developmentally appropriate motor activities) completed the year-long study. Body composition [lean body and fat mass (LBM, FM)], growth/inflammation predictive biomarkers, and Alberta Infant Motor Scale (AIMS) were assessed.

RESULTS

AIMS at 1 year correlated with LBM (r = 0.32, p < 0.001) in the whole cohort. However, there was no effect of the intervention. LBM increased by ~3685 g (p < 0.001)); insulin-like growth factor-1 (IGF-1) was correlated with LBM (r = 0.36, p = 0.002). IL-1RA (an inflammatory biomarker) decreased (-75%, p < 0.0125). LBM and bone mineral density were significantly lower and IGF-1 higher in the females at 1 year.

CONCLUSIONS

We found an association between neuromotor development and LBM suggesting that motor activity may influence LBM. Our particular intervention was ineffective. Whether activities provided largely by caregivers to enhance motor activity in prematurely born infants can affect the interrelated (1) balance of growth and inflammation mediators, (2) neuromotor development, (3) sexual dimorphism, and/or (4) body composition early in life remains unknown.

MACRONUTRIENTS OF MOTHERS' MILK OF VERY LOW BIRTH WEIGHT INFANTS: ANALYSIS ACCORDING TO GESTATIONAL AGE AND MATERNAL VARIABLES

Objective:

To analyze the composition of macronutrients present in the milk of mothers of preterm newborn infants (PTNB) - protein, fat, carbohydrate, and calories - by gestational age (GA), chronological age (CA) and maternal variables.

Methods:

Longitudinal study that analyzed 215 milk samples from the 51 mothers of PTNB admitted in three Neonatal Intensive Care Units of Rio de Janeiro from May/2013-January/2014. Milk collection was performed by pickup pump, on a fixed day of each week until discharge. The spectrophotometric technique with Infrared Analysis (MilkoScan Minor 104) was used for the quantitative analysis. A sample of 7 mL of human milk was taken from the total volume of milk extracted by the mother. The data was grouped by GA (25-27, 28-31, 32-36, 37-40 weeks) and by CA (zero to 4, 5-8, 9-12, 13-16 weeks).

Results:

Protein, carbohydrate, fat and calories did not show any pattern of change, with no difference among groups of GA. When the macronutrients were analyzed by groups of CA, protein decreased, with significant difference between the first two groups of CA. Carbohydrates, fat and calories presented increasing values in all groups, without significant differences. Weight gain during pregnancy, maternal hypertension and maternal age were associated with changes in fat and calories in the first moment of the analysis of milk.

Conclusions:

There was a significant decrease in the levels of protein during the first eight weeks after birth. CA may be an important factor in the composition of human milk.

Impact of introducing a standardized nutrition protocol on very premature infants' growth and morbidity

Background

Inappropriate nutritional intake in premature infants may be responsible for postnatal growth restriction (PGR) and adverse long-term outcomes.

Objective

We evaluated the impact of an updated nutrition protocol on very premature infants’ longitudinal growth and morbidity, and secondly the compliance to this new protocol.

Design

All infants born between 26–32 weeks gestation (GA) were studied retrospectively during two 6-month periods before (group 1) and after (group 2) the introduction of an optimized nutrition protocol, in a longitudinal comparative analysis.

Results

158 infants were included; 72 before and 86 after the introduction of the protocol (Group 1: (mean±SD) birthweight (BW) 1154±276 g, GA 29.0±1.4 weeks; Group 2: BW 1215±332 g, GA 28.9±1.7 weeks). We observed growth improvement in Group 2 more pronounced in males (weight z-score) at D42 (−1.688±0.758 vs. −1.370±0.762, p = 0.045), D49 (−1.696±0.776 vs. −1.370±0.718, p = 0.051), D56 (−1.748±0.855 vs. −1.392±0.737, p = 0.072), D63 (−1.885±0.832 vs. −1.336±0.779 p = 0.016), and D70 (−2.001±0.747 vs. −1.228±0.765 p = 0.004). There was no difference in females or in morbidities between the groups. We observed low compliance to the protocol in both groups: similar energy intake but higher lipid intake in Group 1 and higher protein intake in Group 2.

Conclusion

The quality of nutritional care with a strictly-defined protocol may significantly improve weight gain for very preterm infants. As compliance remained low, an educational reinforcement is needed to prevent PGR.

Clinical trial registration

This retrospective study was registered by ClinicalTrials.gov under number NCT03217045, and by the CNIL (Commission Nationale de l’Informatique et des Libertés) under study number R2015-1 for the Maternity of the CHRU of Nancy.

Growth patterns and body composition in former extremely low birth weight (ELBW) neonates until adulthood: a systematic review

Preterm infants are obviously born lighter and shorter, with smaller head circumferences than normal birth weight term born neonates. They also have a different body composition. Compromised growth is associated with adverse health outcomes. Both growth retardation and accelerated growth are suggested to cause metabolic, cardiovascular, and renal complications. Reviews regarding growth and body composition in preterm infants often do not differentiate between birth weight and gestational age. The purpose of this systematic review is to assemble growth data, specific in extremely low birth weight children. Different databases were searched for studies regarding growth and body composition in former extremely low birth weight infants until adulthood. We compared height, weight, head circumference, body mass index, fat mass, lean mass, fat distribution, and body water to matched normal birth weight controls and the World Health Organization growth charts. Studies consistently reported that former extremely low birth weight neonates experience a period of accelerated postnatal growth, but they achieve lower anthropometric parameters than normal birth weight children. There is no consensus about differences in body composition and how to measure this.Conclusion: Although extremely low birth weight infants exhibit a period of catch-up growth, their growth remains retarded later in life. Further research is needed to investigate body composition and the associated risk of cardiovascular diseases or metabolic syndrome.What is Known:• Extremely low birth weight infants have lower anthropometric parameters and a different body composition at birth and term-corrected age than normal birth weight infants.• Former extremely low birth weight infants also have a higher risk on adverse cardiovascular health outcomes in later life.What is New:• After hospital discharge, extremely low birth weight neonates remain smaller and probably also lighter, with smaller head circumferences at each corrected age throughout childhood and adolescence when compared to normal birth weight infants or the World Health Organization growth charts. It is not clear whether extremely low birth weight infants reach a lower or similar body mass index score as normal birth weight infants.• There is a lack of (long-term) information on body composition in extremely low birth weight infants.

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.

Extremely Preterm Infants Have a Higher Fat Mass Percentage in Comparison to Very Preterm Infants at Term-Equivalent Age

Background: Early nutritional support of preterm infants is important because it influences long-term health and development. Body composition has an influence on cardiovascular disease, metabolic syndrome, and neurocognitive outcome in the long term. Objective: To assess body composition in preterm infants <32 weeks of gestation at term-equivalent age and to analyze the influence of an optimized nutritional approach. Methods: This is a prespecified secondary outcome analysis of a prospective observational study comparing the body composition in regard to gestational age. The preterm infants were classified according to gestational age as extremely preterm infants (<28 weeks gestation at birth) and very preterm infants (≥28 weeks gestation at birth) and according to weight percentile as appropriate for gestational age and small for gestational age. Body composition was determined by air displacement plethysmography using the PEA POD. The preterm infants obtained nutrition according to the ESPGHAN 2010 Guidelines. Results: Seventy-four preterm infants were analyzed. The mean (SD) gestational age was 28.7 (2.4) weeks, and birth weight was 1,162 (372) g. Fat mass percentage was significantly higher in extremely preterm infants in comparison to very preterm infants [17.0, 95% confidence interval (CI) 15.9-18.1 vs. 15.5, 95% CI 14.7-16.2]. There was no significant difference of fat mass percentage according to weight percentiles. Conclusions: Extremely preterm infants had a significantly higher fat mass percentage compared to very preterm infants at term-equivalent age. There was no significant difference of fat mass percentage according to weight percentiles.

Chest circumference in full-term newborns: how can it be predicted?

Background

Although over the years a number of studies have used chest circumference (CC) as a sensitive tool to identify the health status of infants, a particularly important aspect for this population is the lack of data on normal values and prediction equations. In order to facilitate and validate the interpretation of CC data in newborn (NB), the aim was to study the relation between CC and other anthropometric variables and develop a predictive equation for CC in a population of full-term newborns.

Methods

Cross-sectional study, carried out with full-term infants. The anthropometric (CC, head circumference - HC, length, age and weight) and hemodynamic variables were evaluated during the first 24 h of life. Bivariate analysis was performed between CC and HC, weight, length and type of delivery, followed by multiple linear regression analysis, including variables that were significant in the bivariate analysis. For data analysis, we used the SPSS program, considering p < 0.05 and 95% CI.

Results

The birth weight of the 120 NB varied between 2580 and 4225 g (mean 3360 g) and the gestational age between 37 and 42 weeks (mean 39 weeks). Approximately 61% of the sample were delivered vaginally and 67 (56%) were boys. The variables that remained statistically associated with CC after multivariate analysis were weight (β 0.003, CI: 0.002: 0.003, p = 0.001) and HC (β 0.287, CI: 0.156: 0.417, p = 0.001). For the linear regression model, the predictive equation of CC was 14.87+ (0.003 x weight) + (0.287 x HC), with a prediction of 76%.

Conclusion

The results show a positive correlation between CC and weight, length and HC, and based on the linear regression model, the predictive equation for CC is based only on weight and HC.

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.

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.