Is term newborn body composition being achieved postnatally in preterm infants?

Mid-arm circumference is a reliable method to estimate adiposity in preterm and term infants

BACKGROUND

Premature birth is associated with increased adipose deposition after birth. Standard anthropometry (body weight, length, and head circumference) may not adequately assess fat deposition. Validated methods to assess adiposity are needed to optimize growth quality in preterm infants. The purpose of this study was to identify covariates of infant body fat.

METHODS

Air displacement plethysmography (ADP), standard anthropometry, and body circumferences were measured at hospital discharge in preterm (n = 28; 31-35 wk postmenstrual age (PMA)) and term (n = 28; 38-41 wks PMA) infants.

RESULTS

Body weight, length, and head circumference were lower for preterm infants (P < 0.05) at hospital discharge compared with that of term infants. Despite smaller body size and younger PMA, preterm infant percent body fat (%BF) by ADP was 12.33 ± 4.15% vs. 9.64 ± 4.01% in term infants (P = 0.01). Mid-arm circumference (MAC) is a covariate of %BF in both preterm and term infants (adjusted R(2) = 0.49; P < 0.001). In preterm infants alone, MAC accounted for 60.4% of the variability of percent body fat (%BF) by ADP (P < 0.01).

CONCLUSIONS

Preterm infants have increased body fat deposition as they approach term-corrected age, and MAC is a reliable, low-cost measure for monitoring infant body fat deposition in preterm and term infants.

Feasibility study: Assessing the influence of macronutrient intakes on preterm body composition, using air displacement plethysmography

AIM

Preterm nutrition guidelines target nutrient accretion and growth at intrauterine rates, yet at term equivalent age, the phenotype of the preterm infant differs from that of term infants. Monitoring early changes in preterm body composition (BC) in response to macronutrient intakes may facilitate our understanding of how best to meet preterm nutrition and growth targets.

METHOD

Macronutrient intakes based on milk analysis were calculated from birth for infants born <33 weeks gestation. BC was measured in the PEA POD when infants were thermodynamically stable, free of intravenous lines and independent of respiratory support. Subsequent BC measurements were taken at least fortnightly until term age. Regression analysis was used to assess macronutrient influences on changes in BC.

RESULTS

Median (range) gestation and birthweight of preterm infants (n = 27) were 29 (25-32) weeks and 1395 (560-2148) g, respectively. The youngest corrected gestational and postnatal ages that infants qualified for a PEA POD measurement were 31.86 and 1.43 weeks, respectively. Fat and total energy intakes were positively associated with increasing fat mass. Protein (with carbohydrate) intake was positively associated with increasing fat-free mass.

CONCLUSION

Preterm infants can be measured in the PEA POD as early as 31 weeks corrected gestational age and the method appears sufficiently sensitive to detect influences of macronutrient intake on changes in BC.

The ProVIDe study: the impact of protein intravenous nutrition on development in extremely low birthweight babies

BACKGROUND

Preterm birth and very small size at birth have long-term effects on neurodevelopment and growth. A relatively small percentage of extremely low birthweight babies suffer from severe neurological disability; however, up to 50% experience some neurodevelopmental or learning disability in childhood. Current international consensus is that increased protein intake in the neonatal period improves both neurodevelopment and growth, but the quantum of protein required is not known. This trial aims to assess whether providing an extra 1 to 2 g.kg(-1).d(-1) protein in the first 5 days after birth will improve neurodevelopmental outcomes and growth in extremely low birthweight babies.

METHODS/DESIGN

The ProVIDe study is a multicentre, two-arm, double-blind, parallel, randomised, controlled trial. In addition to standard intravenous nutrition, 430 babies with a birthweight of less than 1000 g who have an umbilical arterial line in situ will be randomised in 1:1 ratio to receive either an amino acid solution (TrophAmine®) or placebo (saline) administered through the umbilical arterial catheter for the first 5 days. Exclusion criteria are admission to neonatal intensive care more than 24 h after birth; multiple births of more than 2 babies; known chromosomal or genetic abnormality, or congenital disorder affecting growth; inborn error of metabolism, and in danger of imminent death.

PRIMARY OUTCOME

Survival free from neurodevelopmental disability at 2 years' corrected age, where neurodevelopmental disability is defined as cerebral palsy, blindness, deafness, developmental delay (standardised score more than 1 SD below the mean on the cognitive, language or motor subscales of the Bayley Scales of Infant Development Edition 3), or Gross Motor Function Classification System score ≥ 1.

SECONDARY OUTCOMES

Growth, from birth to 36 weeks' corrected gestational age, at neonatal intensive care discharge and at 2 years' corrected age; body composition at 36 to 42 weeks' corrected postmenstrual age and at 2 years' corrected age; neonatal morbidity, including length of stay; nutritional intake.

DISCUSSION

This trial will provide the first direct evidence of the effects of giving preterm babies a higher intake of intravenous protein in the first week after birth on neurodevelopmental outcomes at 2 years corrected age.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12612001084875.

Do recommended protein intakes improve neurodevelopment in extremely preterm babies?

OBJECTIVE

To determine whether achieving recommended protein intakes for extremely low birthweight (ELBW; birth weight <1000 g) babies, resulting in better growth, improves neurodevelopmental outcomes.

DESIGN

A prospective cohort study of ELBW babies before and after the introduction of a new nutritional policy designed to meet international consensus protein recommendations. Forty-five children born 'before' and 42 born 'after' the policy change were assessed at 2 years' corrected age (CA). Associations between nutritional intakes, growth and neurodevelopmental outcome (Bayley Scales of Infant and Toddler Development, Third edition (Bayley-III), motor and sensory impairment) were assessed using univariate and multivariate analyses.

RESULTS

Bayley-III cognitive (mean (SD) 96 (12) vs 96 (15)), motor (96 (13) vs 95 (15)) or language scores (89 (11) vs 91 (17)) were not different between the 'before' and 'after' cohorts. In the 'before' cohort, motor scores were positively associated with enteral nutrition intakes and growth velocity. Neither were sensory impairments different between groups (visual impairment 4 vs 2, hearing impairment 2 vs 0) nor was the gross motor function classification score (any cerebral palsy 2 vs 1).

CONCLUSIONS

In this prospective cohort study, increasing intravenous and enteral protein intakes to recommended levels in the first month after birth was not associated with improved cognitive, language or motor scores or decreased sensory impairments at 2 years' CA despite significantly improved early growth and reduced postnatal faltering growth. Appropriate randomised controlled trials are needed to answer definitively whether higher early protein intakes improve neurodevelopmental outcome in this population.

Neonatal Body Composition: Measuring Lean Mass as a Tool to Guide Nutrition Management in the Neonate

Neonatal nutrition adequacy is often determined by infant weight gain. The aim of this review is to summarize what is currently known about neonatal body composition and the use of body composition as a measure for adequate neonatal nutrition. Unlike traditional anthropometric measures of height and weight, body composition measurements account for fat vs nonfat mass gains. This provides a more accurate picture of neonatal composition of weight gain. Providing adequate neonatal nutrition in the form of quantity and composition can be a challenge, especially when considering the delicate balance of providing adequate nutrition to preterm infants for catch-up growth. Monitoring weight gain as fat mass and nonfat mass while documenting dietary intake of fat, protein, and carbohydrate in formulas may help provide the medical community the tools to provide optimal nutrition for catch-up growth and for improved neurodevelopmental outcomes. Tracking body composition in term and preterm infants may also provide critical future information concerning the nutritional state of infants who go on to develop future disease such as obesity, hypertension, and hyperlipidemia as adolescents or adults.

Boys who are born preterm show a relative lack of fat-free mass at 5 years of age compared to their peers

AIM

Prematurity is associated with features of metabolic syndrome in young adulthood. We investigated the body composition and blood pressure of children born preterm.

METHODS

A longitudinal, observational study was conducted with preterm infants who had a birth weight of <1500 g and a gestational age of <32 weeks. Growth and body composition were assessed by air displacement plethysmography at term equivalent age and at school age and were compared to those of 61 healthy, term breastfed subjects.

RESULTS

A total of 63 preterm infants were enrolled. At term equivalent age, growth and fat-free mass were lower in preterm infants than in term newborns, but fat mass was higher. At 5 years of age, children born preterm were still lighter and shorter than children born at term. When the results were analysed by gender, the fat-free mass index was lower in boys born preterm than in their peers (12.1 ± 1.1 versus 13.0 ± 1.0 kg/h(2) p < 0.005), whereas no difference was detected among girls. Diastolic blood pressure was higher in children born preterm than in children born at term (61.14 ± 7.8 vs 56.69 ± 8.2 mmHg, p = 0.009).

CONCLUSION

Boys born preterm showed a relative lack of fat-free mass at school age compared to their peers.

Body composition at birth in preterm infants between 30 and 36 weeks gestation

BACKGROUND

The American Academy of Pediatrics calls for aggressive management of preterm infants to achieve body composition approximating that of the healthy infant in utero. Air displacement plethysmography (ADP) has been validated for assessment of body composition in preterm infants and could be used to monitor their nutritional status during hospitalization. Comparative datasets on body composition at birth among healthy, live-born preterm infants are lacking.

OBJECTIVE

The aim of this study is to provide the first descriptive fat mass (FM) and fat-free mass (FFM) data from healthy newborn preterm infants at birth as a proxy for healthy in utero body composition.

METHODS

Body mass and volume were obtained using ADP within 72 h of birth in 98 singleton, appropriate-for-gestational-age preterm infants. FM and FFM were calculated using the Fomon equation.

RESULTS

Measurement with ADP was feasible and well tolerated by infants as young as 30 weeks gestation and <72 h of age. FFM and FM increased linearly over the gestational age range period at rates of 171 and 46 g week(-1) , respectively. Mean values obtained by ADP by gestational week were similar to the previously published reference data from chemical analysis on stillbirths.

CONCLUSIONS

Body composition assessment using ADP is feasible in newborn preterm infants and provides group estimates similar to that of the reference fetus. In the future, integrating body composition information into the nutritional management of preterm infants may help to identify new strategies to optimize growth and development in this vulnerable population.

Skinfold thickness of preterm newborns when they become late preterm infants

BACKGROUND

Nutrition of very low-birth-weight newborns is important for a good physical and neurologic outcome. Body composition assessment, together with anthropometric measurements, is considered necessary to monitor adequate nutrition and growth. Objectives of this study were to assess body fat changes in newborns ≤32 weeks gestation by weekly skinfold thickness (SFT) measurements and to compare them with those of late preterm infants born at 34, 35, and 36 weeks once they reached 34, 35, and 36 weeks corrected age (CA).

MATERIALS AND METHODS

Preterm infants ≤32 weeks gestation had SFT measured from 4 body sites, including biceps, triceps, and subscapulary and suprailiac regions, by a Holtain caliper starting from 48 hours of age at weekly intervals until 34, 35, and 36 weeks CA. The measurements were compared with those of late preterm controls born at 34, 35, and 36 weeks gestation.

RESULTS

There were 37 preterm infants in the patient group. When reaching 34, 35, and 36 weeks CA, preterm infants had higher SFT values compared with controls in all body sites. Median and range of total SFT were 14.6 mm (9.6-18.9 mm) in patients and 11 mm (7.8-16.4 mm) in controls at 34 weeks CA, 15.5 mm (10.7-21.8 mm) in patients and 12.3 mm (7-17 mm) in controls at 35 weeks CA, and 16.4 mm (11.8-23.7 mm) in patients and 12.9 mm (7-17.8 mm) in controls at 36 weeks CA (P = .001 in all). No sex difference was observed at 34 and 35 weeks.

CONCLUSION

These results show that preterm infants start accumulating excess fat even from early weeks of life. Careful assessment of growth by tools other than simple anthropometric measurements is essential to avoid future complications.

No relative increase in intra-abdominal adipose tissue in healthy unstressed preterm infants at term

BACKGROUND

Preterm infants may be at risk for altered adiposity, a known risk factor for unfavorable metabolic and cardiovascular outcomes.

OBJECTIVES

The aim was to compare body composition (total body fat mass (FM), subcutaneous and intra-abdominal adipose tissue (AT)) between infants born preterm and at term.

METHODS

We conducted an observational, cross-sectional study that involved 50 infants born preterm free from major co-morbidities and 34 term healthy breastfed infants. Anthropometric measurements, body composition (total body FM, subcutaneous and intra-abdominal AT) were assessed at 40-42 weeks postconceptional age for preterm infants and within 15 days of birth for term infants. Total body FM was assessed by an air displacement plethysmography system and subcutaneous abdominal and intra-abdominal AT were assessed by magnetic resonance imaging using a commercially available software program.

RESULTS

Compared to term infants, mean (SD) total body FM (g) (636.7 (247) vs. 418.4 (253), p < 0.0001) and mean (SD) subcutaneous abdominal AT (g) (123 (36) vs. 98.9 (22), p < 0.001) were significantly higher in preterm infants but mean (SD) fat-free mass (g) (2,530 (420) vs. 2,965 (389), p < 0.0001) and mean (SD) intra-abdominal AT (10.9 (5.2) vs. 18.2 (13.2), p = 0.001) were significantly lower.

CONCLUSIONS

In the absence of severe illness during the hospital stay, prematurity, although associated with increased total body FM, does not appear to be associated with a relative increase in intra-abdominal AT compared to term infants.

Infant body composition in the PEA POD® era: what have we learned and where do we go from here?

The availability of clinically feasible infant body composition assessment can inform current questions regarding the developmental origins of chronic disease. A strategic approach will facilitate more rapid advancement in knowledge. The objective of this study was to summarize published evidence and ongoing research activity in infant body composition using the PEA POD® infant body composition system. All published studies using the PEA POD® were identified and grouped according to study population and question. All centers with PEA POD® units were invited to participate in an online survey regarding past, current and future PEA POD® use, and results were analyzed using descriptive statistics. The resulting information was used to identify gaps or limitations in existing knowledge, thus highlighting potential research priorities. Twenty-seven published articles were identified and grouped into six research themes. Although the number of infants studied is significant in some areas, interpretation of data is limited by methodological differences. Survey responses were received from 16 of ∼60 centers. Research themes echoed those identified from the published literature. Controlling for or reporting potential confounding variables is essential for understanding infant body composition data. Measurement of health outcome variables would be helpful in identifying associations.

Determinants of body composition in preterm infants at the time of hospital discharge

BACKGROUND

Preterm infants have a higher fat mass (FM) percentage and a lower fat-free mass (FFM) than do term infants at the time of hospital discharge.

OBJECTIVE

We determined perinatal and nutritional factors that affect the body composition of preterm infants at discharge.

DESIGN

A total of 141 preterm infants born at <35 wk of gestation and admitted to Nantes University Hospital Neonatology Unit over a period of 2 y were enrolled. Nutritional intake and growth were monitored during hospitalization. Body composition was assessed by using air-displacement plethysmography at discharge. FFM was compared with reference data in term infants according to sex and gestational age.

RESULTS

Linear regression produced an excellent model to predict absolute FFM from perinatal characteristics and nutrition (R(2) = 0.82) but not the FM percentage (R(2) = 0.24). Gestational and postnatal ages played an equal role in absolute FFM accretion, as did the initial growth (between birth and day 5) and growth between day 5 and discharge. Antenatal corticosteroid treatment slightly reduced FFM accretion. As concerns nutritional intake, a higher protein:energy ratio at days 10 and 21 was significantly associated with decreased risk of an FFM deficit when preterm infants were compared with reference values for term infants. Boys had higher risk of an FFM deficit than did girls.

CONCLUSION

The initial growth and quality of nutrition were significantly associated with absolute FFM accretion during a hospital stay in preterm infants. This trial was registered at clinicaltrials.gov as NCT01450436.

Linear growth and neurodevelopmental outcomes

Despite advances in care, preterm infants exhibit disproportionate growth and neurodevelopmental delay attributable to both nutritional and nonnutritional factors. These infants have prolonged linear stunting and decreased fat-free mass compared with their term counterparts. These 2 metrics index organ growth and development (including the brain) and protein accretion. Protein, along with carbohydrates, fats, and zinc, plays key roles in brain development, and deficiencies can lead to linear growth failure, abnormalities in the growth hormone axis, and developmental delay. Optimization of nutrition, including protein intake, decreasing inflammatory episodes, and enhancing the growth hormone axis will likely improve long-term outcomes.

Preterm infant linear growth and adiposity gain: trade-offs for later weight status and intelligence quotient

OBJECTIVE

To examine trade-offs between cognitive outcome and overweight/obesity in preterm-born infants at school age and young adulthood in relation to weight gain and linear growth during infancy.

STUDY DESIGN

We studied 945 participants in the Infant Health and Development Program, an 8-center study of preterm (≤37 weeks gestational age), low birth weight (≤2500 g) infants from birth to age 18 years. Adjusting for maternal and child factors in logistic regression, we estimated the odds of overweight/obesity (body mass index [BMI] ≥85th percentile at age 8 or ≥25 kg/m(2) at age 18) and in separate models, low IQ (<85) per z-score changes in infant length and BMI from term to 4 months, from 4 to 12 months, and from 12 to 18 months.

RESULTS

More rapid linear growth from term to 4 months was associated with lower odds of IQ <85 at age 8 years (OR, 0.82; 95% CI, 0.70-0.96), but higher odds of overweight/obesity (OR, 1.27; 95% CI, 1.05-1.53). More rapid BMI gain in all 3 infant time intervals was also associated with higher odds of overweight/obesity, and BMI gain from 4-12 months was associated with lower odds of IQ <85 at age 8. Results at age 18 were similar.

CONCLUSION

In these preterm, low birth weight infants born in the 1980s, faster linear growth soon after term was associated with better cognition, but also with a greater risk of overweight/obesity at age 8 years and 18 years. BMI gain over the entire 18 months after term was associated with later risk of overweight/obesity, with less evidence of a benefit for IQ.

Prematurity is not associated with intra-abdominal adiposity in 5- to 7-year-old children

OBJECTIVE

To compare body composition and abdominal fat partitioning between 5- to 7-year old children born preterm and born at term. We hypothesized children born preterm to have a higher body fat percentage and higher percentage of intra-abdominal adipose tissue (%IAAT) compared with their peers born at term.

STUDY DESIGN

A total of 236 children aged 5-7 years, ie, 116 children born preterm (gestational age 29.8 ± 2.6 [30; 24-33] weeks [mean ± SD {median; range}]) and 120 children born at term were included. Body composition was measured by bioelectrical impedance analysis and %IAAT by magnetic resonance imaging. Body mass index, skin fold thickness, and waist-to-hip ratio were investigated as further measures of body composition. Dietary records were compared between both groups.

RESULTS

Children born preterm were shorter (120 cm vs 123 cm, P < .001), lighter (21.8 kg vs 24.3 kg, P < .001), and had a lower body mass index (15.1 kg/m(2) vs 15.9 kg/m(2), P = .003) compared with controls. There were no differences in %IAAT (n = 154), and body fat mass although energy uptake was higher in preterms (335 kJ/kg/d vs 302 kJ/kg/d, P = .03).

CONCLUSIONS

At the age of 5-7 years, children born preterm showed neither increased fat mass nor intra-abdominal adiposity.

Nutrition and growth in infants born preterm from birth to adulthood

Prevention of extra-uterine growth retardation is of extreme importance, as the achievement of adequate growth has been associated with a favorable neurodevelopmental outcome through childhood. In addition, as disturbances in growth that take place early in life may affect adult health, a full understanding of the growth trajectory of very-low-birth-weight infants is also advisable. This review will focus attention on the nutritional strategies proposed during hospital admission and after discharge in order to limit extra-uterine growth retardation in preterm infants. The dynamic changes that characterize growth of infants born preterm from birth up to adulthood will also be addressed.

Novel noninvasive anthropometric measure in preterm and full-term infants: normative values for waist circumference:length ratio at birth

BACKGROUND

Waist circumference:length ratio (WLR) and ponderal index (PI) appear to be useful markers of visceral and total adiposity, respectively. However, there are no normative birth data across the full range of gestational ages.

METHODS

In this retrospective cohort study of 500 preterm and 1,426 full-term infants, born in 1998 and 2008 at three military hospitals, the percentile growth curves for WLR and PI were calculated. There were no sex differences, and results were combined to obtain values from 26 to 42 wk gestation.

RESULTS

Between 26 and 42 wk gestation, median birth WLR increased from 0.55 to 0.62, and median PI increased from 21.1 to 25.6. The adjusted mean WLR at birth among infants born <34 wk increased from 0.55 in 1998 to 0.58 in 2008 (P = 0.048), suggesting that early-preterm infants born in 2008 had greater abdominal adiposity than those born in 1998.

CONCLUSION

We report normative birth data for WLR and PI in preterm and full-term infants by gestational age and sex. WLR and PI may be useful as clinical markers of visceral and overall adiposity. In conjunction with other anthropometric measures, WLR and PI may be useful to monitor postnatal nutrition and growth and assess risk for later obesity and cardiometabolic disorders.

Bioelectrical impedance analysis for assessment of fluid status and body composition in neonates--the good, the bad and the unknown

BACKGROUND/OBJECTIVES

There is a critical need for improved technologies to monitor fluid balance and body composition in neonates, particularly those receiving intensive care. Bioelectrical impedance analysis meets many of the criteria required in this environment and appears to be effective for monitoring physiological trends.

SUBJECT/METHODS

The literature regarding the use of bioelectrical impedance in neonates was reviewed.

RESULTS

It was found that prediction equations for total body water, extracellular water and fat-free mass have been developed, but many require further testing and validation in larger cohorts. Alternative approaches based on Hanai mixture theory or vector analysis are in the early stages of investigation in neonates.

CONCLUSIONS

Further research is required into electrode positioning, bioimpedance spectroscopy and Cole analysis in order to realise the full potential of this technology.

Mechanical-tactile stimulation (MTS) intervention in a neonatal stress model alters adult adipose tissue deposition and prevents hyperinsulinemia in male rats

Preterm infants are exposed to numerous stressors during hospitalization and by term corrected gestational age they have lower body weight but a greater proportion of total body as well as abdominal visceral adipose tissue (VAT) accumulation. Greater abdominal VAT stores have a known association with metabolic syndrome. Mechanical-tactile stimulation (MTS) improves modulation of stress response in both humans and rodents. We hypothesize that MTS, administered during an established model of neonatal stress, would decrease stress-driven adiposity and prevent associated metabolic imbalances in adult rats. Neonatal stress, administered to rat pups from postnatal days 5 to P9, consisted of needle puncture and hypoxic/hyperoxic challenge during 60 min of maternal separation (STRESS; n=20). Mechanical-tactile stimulation (MTS; n=20) was administered to rat pups for 10 min during maternal separation in the stress protocol. Control animals received standard care (CTL; n=20). MRI measured adult (P120) abdominal total fat mass, subcutaneous (SAT) and visceral adipose tissue (VAT). Body weight and fasting serum adiponectin, leptin, glucose, insulin, and corticosterone were also measured. STRESS results in elevated VAT/SAT ratio compared to CTL but lower abdominal total fat mass and abdominal SAT. STRESS males experience hyperinsulinemia. Both STRESS and MTS had elevated leptin with lower adiponectin and corticosterone compared to CTL. In summary, neonatal stress promotes greater abdominal VAT accumulation and, in males, caused hyperinsulinemia and hypoadiponectinemia. Importantly, MTS normalized the VAT/SAT ratio and prevented hyperinsulinemia. We speculate that MTS ameliorates some of the negative metabolic consequences of early life perturbations due to neonatal stress exposure.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULT

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

CONCLUSION

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

Massage improves growth quality by decreasing body fat deposition in male preterm infants

OBJECTIVES

To assess the effect of massage on weight gain and body fat deposition in preterm infants.

STUDY DESIGN

Preterm infants (29-32 weeks) were randomized to the massage group (n = 22, 12 girls, 10 boys) or the control group (n = 22, 12 girls, 10 boys). Treatment was masked with massage or control care administered twice-daily by licensed massage therapists (6 d/wk for 4 weeks). Body weight, length, Ponderal Index (PI), body circumferences, and skinfold thickness (triceps, mid-thigh, and subscapular [SSF]) were measured. Circulating insulin-like growth factor I, leptin, and adiponectin levels were determined by enzyme-linked immunosorbent assay. Daily dietary intake was collected.

RESULTS

Energy and protein intake as well as increase in weight, length, and body circumferences were similar. Male infants in the massage group had smaller PI, triceps skinfold thickness, mid-thigh skinfold thickness, and SSF and increases over time compared with control male infants (P < .05). Female infants in the massage group had larger SSF increases than control female infants (P < .05). Circulating adiponectin increased over time in control group male infants (group × time × sex interaction, P < .01) and was correlated to PI (r = 0.39, P < .01).

CONCLUSIONS

Twice-daily massage did not promote greater weight gain in preterm infants. Massage did, however, limit body fat deposition in male preterm infants. Massage decreased circulating adiponectin over time in male infants with higher adiponectin concentrations associated with increased body fat. These findings suggest that massage may improve body fat deposition and, in turn, growth quality of preterm infants in a sex-specific manner.

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

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

Implementation of nutritional strategies decreases postnatal growth restriction in preterm infants

Background

Prevention of postnatal growth restriction of very preterm infants still represents a challenge for neonatologists. As standard feeding regimens have proven to be inadequate. Improved feeding strategies are needed to promote growth. Aim of the present study was to evaluate whether a set of nutritional strategies could limit the postnatal growth restriction of a cohort of preterm infants.

Methodology/Principal Findings

We performed a prospective non randomized interventional cohort study. Growth and body composition were assessed in 102 very low birth weight infants after the introduction of a set of nutritional practice changes. 69 very low birth weight infants who had received nutrition according to the standard nutritional feeding strategy served as a historical control group. Weight was assessed daily, length and head circumference weekly. Body composition at term corrected age was assessed using an air displacement plethysmography system. The cumulative parenteral energy and protein intakes during the first 7 days of life were higher in the intervention group than in the historical group (530±81 vs 300±93 kcal/kg, p<0.001 and 21±2.9 vs 15±3.2 g/kg, p<0.01). During weaning from parenteral nutrition, the intervention group received higher parental/enteral energy and protein intakes than the historical control group (1380±58 vs 1090±70 kcal/kg; 52.6±7 vs 42.3±10 g/kg, p<0.01). Enteral energy (kcal/kg/d) and protein (g/kg/d) intakes in the intervention group were higher than in the historical group (130±11 vs 100±13; 3.5±0.5 vs 2.2±0.6, p<0.01). The negative changes in z score from birth to discharge for weight and head circumference were significantly lower in the intervention group as compared to the historical group. No difference in fat mass percentage between the intervention and the historical groups was found.

Conclusions

The optimization and the individualization of nutritional intervention promote postnatal growth of preterm infants without any effect on percentage of fat mass.

Postnatal catch-up fat after late preterm birth

BACKGROUND

Late preterm birth accounts for 70% of preterm births. The aim of the study was to investigate the postnatal weight gain and weight gain composition changes in a cohort of late preterm infants.

METHODS

A total of 49 late preterm infants (mean birth weight 2,496 ± 330 g and gestational age 35.2 ± 0.7 wks) underwent growth and body composition assessment by an air displacement plethysmography system on the fifth day of life, at term, and at 1 and 3 mo of corrected age. The reference group was composed of 40 healthy, full-term, breast-fed infants.

RESULTS

The late preterm infants showed a Δ fat mass gain between birth and term-corrected age equal to 182%. As compared with full-term infants, at term and 1 mo of corrected age mean weight (3,396 ± 390 vs. 3,074 ± 409 g and 4,521 ± 398 vs. 4,235 ± 673 g, respectively) and percentage of fat mass (16.1 ± 4.6 vs. 8.9 ± 2.9 and 22.6 ± 4.2 vs. 17.4 ± 4.0, respectively) were significantly higher in late preterm infants, whereas no difference among groups was found at 3 mo.

CONCLUSION

Rapid postnatal catch-up fat was found in these infants. Further studies are needed to investigate whether this short-term increase in fat mass may modulate the risk of chronic diseases or represent an adaptive mechanism to extrauterine life.

Growth and fat-free mass gain in preterm infants after discharge: a randomized controlled trial

OBJECTIVE

To investigate whether the consumption of a nutrient-enriched formula after hospital discharge determines different growth and weight gain composition in preterm infants according to intra- and extrauterine growth pattern.

METHODS

Two hundred seven preterm infants were randomized at term-corrected age to receive treatment A (term formula) or B (nutrient-enriched formula) up to 6 months of corrected age, using 2 computer-generated randomization lists, 1 for adequate for gestational age (AGA) and 1 for small for gestational age (SGA) infants. Infants were weaned according to our clinical practice after 6 months' corrected age. Anthropometric parameters and body composition by an air displacement plethysmography system were assessed at term and 1, 3, and 6 months' corrected age. Anthropometric parameters were also assessed at 12 months.

RESULTS

Protein intakes were higher in infants receiving treatment B than in infants receiving treatment A at each study point. There were no differences between the feeding groups in weight and length SD scores in either the AGA and SGA group through the study. The mean head circumference values were higher in AGA infants receiving treatment B than in AGA infants receiving treatment A at 6 and 12 months, whereas at 6 months, the percentage of fat mass was lower. No difference in body composition was detected among SGA infants through the study.

CONCLUSIONS

This randomized controlled trial demonstrates the beneficial effect of the consumption of a nutrient-enriched formula after hospital discharge by AGA infants both in terms of head circumference growth and fat-free mass gain.

Preterm infants of lower gestational age at birth have greater waist circumference-length ratio and ponderal index at term age than preterm infants of higher gestational ages

OBJECTIVE

To assess anthropometric changes from birth to hospital discharge in infants born preterm and compare with a reference birth cohort of infants born full-term.

STUDY DESIGN

Retrospective chart review was conducted of 501 preterm and 1423 full-term infants. We evaluated birth and hospital discharge weight, length, and waist circumference (WC). WC/length ratio (WLR), ponderal index, and body mass index (BMI) were calculated. Preterm infants were categorized into quartiles (Q1-4) based on birth weight (BW).

RESULTS

At birth mean length, WC, WLR, BMI, and ponderal index were all significantly less for preterm infants in the lowest BW quartile (Q1) than preterm infants in higher BW quartiles or full-term infants. Although their weight, length, and BMI remained significantly less at discharge, preterm infants in Q1 had a disproportionate increase in WLR and ponderal index such that at discharge their WLR and ponderal index were greater than infants in Q2-3 and comparable with infants in Q4 and full-term infants. Discharge WLR and ponderal index in Q1 were significantly higher with decreasing postmenstrual age at birth.

CONCLUSIONS

Preterm infants of a lower birth postmenstrual age have disproportionate increases in WLR and ponderal index that are suggestive of increased visceral and total adiposity.

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

BACKGROUND AND OBJECTIVE

Infants born preterm are significantly lighter and shorter on reaching term equivalent age (TEA) than are those born at term, but the relation with body composition is less clear. We conducted a systematic review to assess the body composition at TEA of infants born preterm.

METHODS

The databases MEDLINE, Embase, CINAHL, HMIC, "Web of Science," and "CSA Conference Papers Index" were searched between 1947 and June 2011, with selective citation and reference searching. Included studies had to have directly compared measures of body composition at TEA in preterm infants and infants born full-term. Data on body composition, anthropometry, and birth details were extracted from each article.

RESULTS

Eight studies (733 infants) fulfilled the inclusion criteria. Mean gestational age and weight at birth were 30.0 weeks and 1.18 kg in the preterm group and 39.6 weeks and 3.41 kg in the term group, respectively. Meta-analysis showed that the preterm infants had a greater percentage total body fat at TEA than those born full-term (mean difference, 3%; P = .03), less fat mass (mean difference, 50 g; P = .03), and much less fat-free mass (mean difference, 460 g; P < .0001).

CONCLUSIONS

The body composition at TEA of infants born preterm is different than that of infants born at term. Preterm infants have less lean tissue but more similar fat mass. There is a need to determine whether improved nutritional management can enhance lean tissue acquisition, which indicates a need for measures of body composition in addition to routine anthropometry.

Evaluation of air-displacement plethysmography for body composition assessment in preterm infants

BACKGROUND

Adiposity may contribute to the future risk of disease. The aim of this study was to evaluate the accuracy and reliability of an air-displacement plethysmography (ADP) system to estimate percentage fat mass (%FM) in preterm infants and to evaluate interdevice reliability in infants.

METHODS

A total of 70 preterm and 9 full-term infants were assessed. The accuracy of ADP measurements was assessed by determining reference %FM values using H(2)(18)O dilution measurement.

RESULTS

Mean %FM by ADP was 5.67 ± 1.84 and mean %FM by H(2)18O dilution was 5.99 ± 2.56. Regression analysis showed that %FM by ADP was associated with %FM by H(2)(18)O dilution (R2 = 0.63, SE of estimate (SEE) = 1.65, P = 0.006). Bland-Altman analysis showed no bias (r = -0.48, P = 0.16) and 95% limits of agreement were -3.40 to 2.76 %FM. There was no difference in mean interdevice reliability %FM values (8.97 vs. 8.55 %FM) between ADP 1 and 2. Regression analysis indicated a low SEE (1.14% FM) and high R2 (0.91); 95% limits of agreement were -1.87 to 2.71 %FM. The regression line did not differ significantly from the line of identity.

CONCLUSION

ADP is a noninvasive, reliable, and accurate technique to measure preterm infants' body composition in both research and clinical settings.

Effect of sex and gestational age on neonatal body composition

To determine the effects of length of gestation and sex on infant body composition, air displacement plethysmography was performed in forty-six full-term neonates at 3 d of life and during the week prior to hospital discharge in 180 preterm neonates. Fat mass, as a percentage of body weight, was higher in preterm than in term infants (13·4 (sd 4·2) v. 10·1 (sd 3·7) %, respectively; P= 0·001). The absolute amount of fat mass did not differ between preterm and full-term newborns (323 (sd 126) v. 335 (sd 138) g; P= 0·58), whereas lean body mass was lower in preterm than in term infants (2055 (sd 280) v. 2937 (sd 259) g, respectively; P< 0·001). Among full-term infants, fat mass was higher in females than in males (11·1 (sd 3·7) v. 9·0 (sd 3·3) %, respectively; P= 0·047), whereas we did not observe any sex difference in preterm infants (13·5 (sd 4·1) v. 13·4 (sd 4·3) %; P= 0·89). Our data suggest that by the time they are discharged from hospital: (1) preterm infants have a higher percentage of body fat than term neonates and (2) this is presumably due to a lesser accretion in lean body mass in the first few weeks of extra-uterine life, particularly in boys.

Customized versus population-based growth curves: prediction of low body fat percent at term corrected gestational age following preterm birth

OBJECTIVE

Compare customized versus population-based growth curves for identification of small-for-gestational-age (SGA) and body fat percent (BF%) among preterm infants.

METHODS

Prospective cohort study of 204 preterm infants classified as SGA or appropriate-for-gestational-age (AGA) by population-based and customized growth curves. BF% was determined by air-displacement plethysmography. Differences between groups were compared using bivariable and multivariable linear and logistic regression analyses.

RESULTS

Customized curves reclassified 30% of the preterm infants as SGA. SGA infants identified by customized method only had significantly lower BF% (13.8 ± 6.0) than the AGA (16.2 ± 6.3, p = 0.02) infants and similar to the SGA infants classified by both methods (14.6 ± 6.7, p = 0.51). Customized growth curves were a significant predictor of BF% (p = 0.02), whereas population-based growth curves were not a significant independent predictor of BF% (p = 0.50) at term corrected gestational age.

CONCLUSION

Customized growth potential improves the differentiation of SGA infants and low BF% compared with a standard population-based growth curve among a cohort of preterm infants.

Development of whole body adiposity in preterm infants

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

Body composition in newborn infants: 5-year experience in an Italian neonatal intensive care unit

The aim of nutrition in neonatology is to achieve a healthy growth that mimics, both in terms of growth rates and quality of growth, that of a normal fetus of the same gestational age. In addition, providing an optimal amount and quality of nutrients significantly contributes to the attainment of a neurodevelopment similar to that of an infant born at term. Yet, a high risk of developing metabolic syndrome in relation to aggressive nutrition and accelerated postnatal growth velocity has been reported in former preterm infants. Considering the strict interrelationship that exists between early nutrition, growth, and subsequent health, the development of body composition in early infancy, in terms of fat mass, may contribute to the long-term "programming" process. Hence, accurate and non-invasive measurement of infant body composition, which evaluates the quality in addition to the amount of weight gain, represents a useful tool for gaining further insight into the relationship between birth weight or time in utero and future development. Preterm infants, including those born small for gestational age, have been reported to develop an increased and/or aberrant adiposity, in addition to postnatal growth retardation, when assessed at term-corrected age. However, within the first 5 months, preterm infants, either born adequate or small for gestational age, show a recovery of fat mass, and attain fat mass values comparable to those of full-term infants assessed at birth. The metabolic consequences of these findings on the long-term health need to be further clarified.

Genetic and environmental components of neonatal weight gain in preterm infants

BACKGROUND AND OBJECTIVES

Postnatal nutrition and subsequent weight gain or failure in the neonatal period are likely regulated by both the environment and the genetic background. With the goal of estimating the variability of postnatal weight gain due to genes and environment, comparison between monozygotic (ie, genetically identical) and dizygotic (genetically similar as 2 siblings) twins can be performed.

METHODS

This study selected a very homogenous set of monozygotic and dizygotic twins who met the following inclusion criteria: gestational age between 30 and 36 weeks, birth weight between 1250 and 2200 g, and length of stay >12 days. Opposite-gender pairs and pairs that differed >20% in terms of birth weight were excluded from this analysis. The outcome measure of this study was the daily weight gain expressed in grams per kilogram per day during the period between day of birth and day of discharge. The average difference between members of a pair was computed in the 2 groups of twins, and heritability was estimated.

RESULTS

The within-pair differences of the outcome measure were lower for monozygotic twins than for dizygotic twins, suggesting a strong genetic component. The total variance of the phenotype under study is explained by 2 sources of variation, additive genetic (87% [95% confidence interval: 67% to 94%]) and unique environment (13% [95% confidence interval: 6% to 33%]) components.

CONCLUSIONS

This high heritability estimate could suggest using this set of criteria to identify genes that regulate postnatal weight gain or failure.

Gender- and gestational age-specific body fat percentage at birth

BACKGROUND

There is increasing evidence that in utero growth has both immediate and far-reaching influence on health. Birth weight and length are used as surrogate measures of in utero growth. However, these measures poorly reflect neonatal adiposity. Air-displacement plethysmography has been validated for the measurement of body fat in the neonatal population.

OBJECTIVE

The goal of this study was to show the normal reference values of percentage body fat (%BF) in infants during the first 4 days of life.

METHODS

As part of a large population-based birth cohort study, fat mass, fat-free mass, and %BF were measured within the first 4 days of life using air-displacement plethsymography. Infants were grouped into gestational age and gender categories.

RESULTS

Of the 786 enrolled infants, fat mass, fat-free mass, and %BF were measured in 743 (94.5%) infants within the first 4 days of life. %BF increased significantly with gestational age. Mean (SD) %BF at 36 to 37⁶/⁷ weeks' gestation was 8.9% (3.5%); at 38 to 39 weeks' gestation, 10.3% (4%); and at 40 to 41⁶/⁷ weeks' gestation, 11.2% (4.3%) (P < .001). Female infants had significantly increased mean (SD) %BF at 38 to 39⁶/⁷ (11.1% [3.9%] vs 9.8% [3.9%]; P = .012) and at 40 to 41⁶/⁷ (12.5% [4.4%] vs 10% [3.9%]; P < .001) weeks' gestation compared with male infants. Gender- and gestational age-specific centiles were calculated, and a normative table was generated for reference.

CONCLUSION

%BF at birth is influenced by gestational age and gender. We generated accurate %BF centiles from a large population-based cohort.

Dried blood spots, pharmacokinetic studies and better medicines for children

Determining circulating drug concentrations in children is an ongoing obstacle to the development of age-appropriate dosing regimens. The requirement for small blood sample volumes in children compared with adults is a significant barrier to obtaining age-specific pharmacokinetic-pharmacodynamic data for this population and hence optimizing the efficacy and safety profile of medicines used by this group. This article discusses the potential for dried blood spot sampling to offer a solution to this issue.

Fat-free mass hydration in newborns: assessment and implications for body composition studies

AIM

Equipment (Pea Pod) offering new possibilities to assess infant body composition has recently become available and has already been used in several studies. In the Pea Pod, body density is converted to body composition using one of two models ('Fomon' or 'Butte') with different water content in fat-free mass (hydration factor, HF). In healthy full-term infants, we assessed HF and its biological variability in 12 newborns and calculated body composition using the two models at 1 and 12 weeks in 108 infants. Body weight and volume were assessed in Pea Pod, and body water was assessed using isotope dilution.

RESULTS

Hydration factor was 80.9% with low biological variability (0.8% of average HF). Body fat (%) was significantly lower at 1 and 12 weeks when calculated using the 'Butte' model than when using the 'Fomon' model. The difference was more pronounced at one than at 12 weeks.

CONCLUSION

  Our HF value agrees with that in the 'Fomon' model, its low biological variability can be reconciled with the statement that Pea Pod is accurate in newborns and 'Fomon' is the best available model for studies in Pea Pod.

Mechanical-tactile stimulation (MTS) during neonatal stress prevents hyperinsulinemia despite stress-induced adiposity in weanling rat pups

Stress in early life negatively influences growth quality through perturbations in body composition including increased fat mass. At term (40 weeks) preterm infants have greater fat mass and abdominal visceral adipose tissue than term-born infants. Mechanical-tactile stimulation (MTS) attenuates the stress response in preterm infants and rodents. We tested the hypothesis that MTS, administered during an established model of neonatal stress, would decrease stress-driven adiposity and prevent associated metabolic imbalances in rat pups. Pups received one of three treatments from postnatal days 5 to P9: Neonatal Stress (Stress; n=20) = painful stimulus and hypoxic/hyperoxic challenge during 60 min of maternal separation; MTS (n=20) = neonatal stress+10 min of MTS; or Control (n=20). Body weight, DXA whole body fat mass (g), MRI subcutaneous and visceral adipose tissue, and fasting adiponectin, leptin, glucose, insulin, and corticosterone were measured at weaning (P21). Stress and MTS weight gain (g/d) were accelerated following neonatal stress with greater fat mass, abdominal subcutaneous adipose tissue, serum adiponectin, leptin, and fasting glucose at weaning (P21). Male Stress and MTS pups had greater visceral adipose tissue depot. Male and female Stress pups were hyperinsulinemic. In summary, neonatal stress compromised body composition by increasing fat mass and abdominal subcutaneous adipose tissue depot, and in males, visceral adipose tissue depot. Importantly, MTS prevented hyperinsulinemia despite of stress-induced adiposity. We conclude that MTS during neonatal stress has the potential to minimize metabolic consequences associated with stress-driven perturbations in fat mass and abdominal adipose depots.

N-3 long-chain polyunsaturated fatty acids prevent excessive fat deposition in adulthood in a mouse model of postnatal nutritional programming

This study investigates whether improved quality of nutrients during early postnatal life has effects on adult metabolic profile and body composition in a murine model of nutritional programming. Male offspring of C57Bl/6j dams received a diet containing 21% energy (En%) as fat of either 100% vegetable oils [control (CTRL)] or 80% vegetable oils/20% tuna fish oil [rich in n-3 long-chain polyunsaturated fatty acids (n-3 LCP)] from postnatal day (PN) 2 to 42. Subsequently, mice of both experimental groups were switched to a western style diet (WSD; 21 En% fat, high saturated fatty acid [FA] content, and cholesterol) until dissection at PN98. Body composition was analyzed by dual x-ray absorptiometry during the WSD challenge. Results showed that a n-3 LCP-rich diet during postnatal life not only reduced fat accumulation by ∼30% during the WSD challenge from PN42 to 98 (p < 0.001) but also led to a healthier plasma lipid profile, healthier plasma glucose homeostasis, and less hypertrophic adipocytes compared with CTRL. This study shows that postnatal nutrition has programming effects on adult body composition and metabolic homeostasis. In addition, it emphasizes that moderate alterations in fat quality during early postnatal life considerably affect adult metabolic health.

Body composition in full-term healthy infants measured with air displacement plethysmography at 1 and 12 weeks of age

AIM

To use Pea Pod, a device based on air displacement plethysmography, to study body composition of healthy, full-term infants born to well-nourished women with a western life-style.

METHODS

Body composition was assessed in 53 girls and 55 boys at 1 week (before 10 days of age) and at 12 weeks (between 77 and 91 days of age).

RESULTS

At 1 week girls contained 13.4 +/- 3.7% body fat and boys 12.5 +/- 4.0%. At 12 weeks, these figures were 26.3 +/- 4.2% (girls) and 26.4 +/- 5.1% (boys). Body fat (%) did not differ significantly between the genders. Body fat (%) at the two measurements was not correlated. At 1 week, the weight (r = 0.20, p = 0.044) and BMI (r = 0.26, p = 0.007) of the infants, but not their body fat (g, %) or fat free mass (g), correlated with BMI before pregnancy in their mothers.

CONCLUSIONS

Pea Pod has potential for use in studies investigating the effect of external (i.e. nutritional status) and internal (i.e. age, gender, gestational age at birth) factors on infant body composition. This may be of value when studying relationships between the nutritional situation during early life and adult health.