Development of whole body adiposity in preterm infants

Defining Body Mass Index Using Weight and Length for Gestational Age in the Growth Assessment of Preterm Infants at Birth

OBJECTIVE

The objectives of this study were to describe (1) body mass indexes (BMIs) using weight and length for gestational age (GA) classifications, and (2) the additional information BMI, as a measure of body proportionality, provides for preterm infant growth assessment and care plans at birth.

STUDY DESIGN

Birth weight, length, and BMI of 188,646 preterm infants (24-36 weeks gestation) admitted to U.S. neonatal intensive care units (Pediatrix Clinical Data Warehouse, 2013-2018) were classified (Olsen curves) as small, appropriate, or large for GA (SGA < 10th, AGA 10-90th, LGA > 90th percentile for GA, respectively). The distribution for the 27 weight-length-BMI combinations was described.

RESULTS

At birth, most infants were appropriate for weight (80.0%), length (82.2%), head circumference (82.9%), and BMI (79.9%) for GA. Birth weight for GA identified approximately 20% of infants as SGA or LGA. Infants born SGA (or LGA) for both weight and length ("proportionate" in size) were usually appropriate for BMI (59.0% and 75.6%). BMI distinguished disproportionate weight for length in infants with SGA or LGA weight at birth (58.3%, 49.9%). BMI also identified 11.4% of AGA weight infants as small or large for BMI ("disproportionate" in size) at birth; only using weight for GA missed these underweight/overweight for length infants.

CONCLUSION

The unique, additional information provided by birth BMI further informs individualized preterm infant growth assessment by providing an assessment of an infant's body proportionality (weight relative to its length) in addition to the routine assessment of weight, length, and head circumference for GA and may better inform care plans and impact outcomes.

KEY POINTS

· Most preterm infants were born AGA for all growth measures.. · AGA weight infants may be under- or overweight for length.. · BMI distinguished body disproportionality in SGA/LGA infants.. · Recommend BMI assessed along with weight, length and head.. · Further research on BMI in preterm infants is needed..

Body composition after implementation of an enhanced parenteral nutrition protocol in the neonatal intensive care unit: a randomised pilot trial

BACKGROUND

Very low birthweight (VLBW) infants are at risk for growth failure and poor neurodevelopment. Optimised parenteral nutrition may help promote optimal growth and development, but concerns that provision of enhanced nutrition may contribute to increased early adiposity and later metabolic disease remain.

AIM

To determine associations between provision of an early enhanced parenteral nutrition protocol or standard parenteral nutrition protocol and growth and body composition for VLBW preterm infants in the neonatal intensive care unit.

SUBJECTS

This is a secondary analysis of data from a clinical trial aimed at assessing the feasibility and safety of randomising VLBW preterm infants to Standard (n = 45) or Intervention (n = 42) parenteral nutrition groups between August 2017 and June 2019.

METHODS

We evaluated associations between weekly infant growth and body composition measurements from n = 55 infants (Standard = 29, Intervention = 26) that were clinically stable enough to have body composition measurements taken before discharge using mixed effects linear regression models.

RESULT

No statistically significant associations between nutrition group and infant growth or body composition measures were observed (p >.05).

CONCLUSION

In this pilot trial, enhanced parenteral nutrition in the first week of life was not associated with significant differences in infant growth or body composition during hospitalisation.

Maternal Pre-Pregnancy Nutritional Status and Infant Birth Weight in Relation to 0-2 Year-Growth Trajectory and Adiposity in Term Chinese Newborns with Appropriate Birth Weight-for-Gestational Age

Being born with appropriate weight-for-gestational age (AGA, ~80% of newborns) is often considered as low risk for future obesity. This study examined differential growth trajectories in the first two years by considering pre- and peri-natal factors among term-born AGA infants. We prospectively investigated 647 AGA infants and their mothers enrolled during 2012-2013 in Shanghai, China, and obtained repeated anthropometric measures at ages 42 days, 3, 6, 9, and 18 months from postnatal care records, and onsite measurements at age 1 and 2 years (skinfold thickness, mid-upper arm circumference (MUAC)). Birthweight was classified into sex-and gestational age-specific tertiles. Among mothers, 16.3% were overweight/obese (OWO), and 46.2% had excessive gestational weight gain (GWG). The combination of maternal prepregnancy OWO and high birthweight tertile identified a subset of AGA infants with 4.1 mm higher skinfold thickness (95% CI 2.2-5.9), 1.3 cm higher MUAC (0.8-1.7), and 0.89 units higher weight-for-length z-score (0.54, 1.24) at 2 years of age with adjustment for covariates. Excessive GWG was associated with higher child adiposity measures at 2 years of age. AGA infants manifested differential growth trajectories by the combination of maternal OWO and higher birthweight, suggesting that additional attention is needed for those "at increased risk" of OWO in early intervention.

The Associations of Birthweight for Gestational Age Status with Its Differential 0-2 Year Growth Trajectory and Blood Pressure at Two Years of Age in Chinese Boys and Girls

The first 1000 days of life represents a critical period for lifelong metabolic health. This study prospectively examined the contrasts between the growth trajectories of large, small, and appropriate sizes for gestational age (LGA, SGA, and AGA) term-born infants in their first two years, and their blood pressure at two years. In 2012-2013, 806 Chinese mother-newborn dyads were enrolled in the Shanghai Obesity and Allergy Birth Cohort Study. Repeated anthropometric measures were obtained at age 42 days, and at 3, 6, 9, 12, 18 and 24 months. Systolic and diastolic blood pressure (SBP, DBP) were measured at two years of age. Linear random effect models were employed to evaluate growth trajectory differences between LGA, SGA, and AGA infants. Of the study infants, 12.4% were LGA and 4.0% SGA. Length, weight, and weight-for-length z-score (ZWFL) were all consistently higher in LGA infants and lower in SGA infants than AGA infants. SGA infants had a higher ZWFL (0.11 unit/month; 95% CI: 0.04, 0.19) and a higher BMI (0.19; 95% CI: 0.09, 0.28 kg/m² per month) growth velocity at age 0-6 months, relative to AGA infants. SGA was associated with 6.4 (0.4-12.4) mmHg higher SBP, and LGA was associated with 2.9 (95% CI -5.2, -0.5) mmHg lower DBP at two years of age in boys, however, not in girls. In conclusion, in this prospective birth cohort with repeated anthropometric measures and BP at two years of age, LGA, SGA, and AGA term-born infants manifested differential patterns of weight growth trajectory and BP, providing new insight into developmental origins of cardiometabolic health.

A. Sørensen T, Elhakeem A, Santos AC, Pinot de Moira A, Heude B, Iñiguez C, Pizzi C, Simons E, Voerman E, Corpeleijn E, Zariouh F, Santorelli G, Inskip HM, Barros H, Carson J, Harris JR, Nader JL, Ronkainen J, Strandberg-Larsen K, Santa-Marina L, Calas L, Cederkvist L, Popovic M, Charles MA, Welten M, Vrijheid M, Azad M, Subbarao P, Burton P, Mandhane PJ, Huang RC, Wilson RC, Haakma S, Fernández-Barrés S, Turvey S, Santos S, Tough SC, Sebert S, Moraes TJ, Salika T, Jaddoe VWV, Lawlor DA, Nybo Andersen AM. Gestational age at birth and body size from infancy through adolescence: An individual participant data meta-analysis on 253,810 singletons in 16 birth cohort studies

BACKGROUND

Preterm birth is the leading cause of perinatal morbidity and mortality and is associated with adverse developmental and long-term health outcomes, including several cardiometabolic risk factors and outcomes. However, evidence about the association of preterm birth with later body size derives mainly from studies using birth weight as a proxy of prematurity rather than an actual length of gestation. We investigated the association of gestational age (GA) at birth with body size from infancy through adolescence.

METHODS AND FINDINGS

We conducted a two-stage individual participant data (IPD) meta-analysis using data from 253,810 mother-child dyads from 16 general population-based cohort studies in Europe (Denmark, Finland, France, Italy, Norway, Portugal, Spain, the Netherlands, United Kingdom), North America (Canada), and Australasia (Australia) to estimate the association of GA with body mass index (BMI) and overweight (including obesity) adjusted for the following maternal characteristics as potential confounders: education, height, prepregnancy BMI, ethnic background, parity, smoking during pregnancy, age at child's birth, gestational diabetes and hypertension, and preeclampsia. Pregnancy and birth cohort studies from the LifeCycle and the EUCAN-Connect projects were invited and were eligible for inclusion if they had information on GA and minimum one measurement of BMI between infancy and adolescence. Using a federated analytical tool (DataSHIELD), we fitted linear and logistic regression models in each cohort separately with a complete-case approach and combined the regression estimates and standard errors through random-effects study-level meta-analysis providing an overall effect estimate at early infancy (>0.0 to 0.5 years), late infancy (>0.5 to 2.0 years), early childhood (>2.0 to 5.0 years), mid-childhood (>5.0 to 9.0 years), late childhood (>9.0 to 14.0 years), and adolescence (>14.0 to 19.0 years). GA was positively associated with BMI in the first decade of life, with the greatest increase in mean BMI z-score during early infancy (0.02, 95% confidence interval (CI): 0.00; 0.05, p < 0.05) per week of increase in GA, while in adolescence, preterm individuals reached similar levels of BMI (0.00, 95% CI: -0.01; 0.01, p 0.9) as term counterparts. The association between GA and overweight revealed a similar pattern of association with an increase in odds ratio (OR) of overweight from late infancy through mid-childhood (OR 1.01 to 1.02) per week increase in GA. By adolescence, however, GA was slightly negatively associated with the risk of overweight (OR 0.98 [95% CI: 0.97; 1.00], p 0.1) per week of increase in GA. Although based on only four cohorts (n = 32,089) that reached the age of adolescence, data suggest that individuals born very preterm may be at increased odds of overweight (OR 1.46 [95% CI: 1.03; 2.08], p < 0.05) compared with term counterparts. Findings were consistent across cohorts and sensitivity analyses despite considerable heterogeneity in cohort characteristics. However, residual confounding may be a limitation in this study, while findings may be less generalisable to settings in low- and middle-income countries.

CONCLUSIONS

This study based on data from infancy through adolescence from 16 cohort studies found that GA may be important for body size in infancy, but the strength of association attenuates consistently with age. By adolescence, preterm individuals have on average a similar mean BMI to peers born at term.

Is small for gestational age status independently correlated with body composition during childhood?

This study aims to examine if small for gestation age (SGA) status is correlated with alterations in body composition at prepuberty, independently of other factors, comparing SGA-born children with appropriate for gestational age (AGA)-born children. We examined anthropometrics, waist circumference, body mass index (BMI), six skinfold thickness, and body composition using the method of bioelectrical impedance in 636 children aged 7 to 10 years. We also considered age, gender, birth mode, mother's age, prepregnancy weight, weight gain during pregnancy, social status, parental BMI, type of feeding, and daily exercise. We examined 636 children at a mean age of 9 years: 106 SGA-born and 530 AGA-born children. SGA as compared to AGA-born children had a lower BMI z-score (0.26 ± 0.89 kg/cm² vs 0.46 ± 0.84 kg/cm², p < 0.050) and a lower lean mass, although that was not statistically significant (24.0 ± 6.6 kg vs 25.6 ± 6.4 kg, p < 0.100). SGA-born children presented no difference in waist circumference or fat mass in comparison to children born AGA. Logistic regression analysis revealed a strong independent negative association between SGA status and BMI (beta =  - 2.33, OR = 0.70 p = 0.019) and SGA status and lean mass (beta =  - 2.43, OR = 0.95 p = 0.010).  Conclusion: Our findings suggest that SGA-born children had a lower BMI as compared to AGA-born subjects, whereas SGA status was negatively associated with BMI and lean mass. What is Known: • Deviant birth weight for gestation has been associated with an increased risk of childhood adiposity. • Evidence remains scarce on whether small for gestational age status affects body composition and obesity later in childhood. What is New: • Among school-aged children, small for gestational age subjects had a lower body mass index as compared to appropriate for gestational age counterparts, whereas small for gestational age status was negatively associated with body mass index and lean mass. • A meticulous observation is needed during childhood in children born with deviant birth weight.

Out of step societal and Darwinian adaptation during evolution is the cause of multiple women's health issues

During human evolution, major changes in our societal conditions and environment took place without sufficient time for concomitant genetic alterations, leading to out of step adaptation and diseases in women. We first discuss recent societal adaptation mismatch (menstrual bleeding; increases in cancers of reproductive organs, endometriosis; mother's nursing; polycystic ovarian syndrome; transgenerational epigenetic modifications), followed by Darwinian out of step adaptation (labor difficulties; sex chromosomes, human diseases and sex disparity in genomic DNA). We discuss the evolutionary basis of menstrual bleeding, followed by recent increases in cancers of reproductive organs and endometriosis. The importance of breastfeeding by mothers is also emphasized. Earlier onset of menarche, decreased rates of childbirths and breastfeeding resulted in increased number of menstrual cycles in a lifetime, coupled with excess estrogen exposure and incessant ovulation, conditions that increased the susceptibility to mammary and uterine cancers as well as ovarian epithelial cancer and endometriosis. Shorter lactation duration in mothers also contributed to more menstrual cycles. We further discuss the evolutionary basis of the prevalent polycystic ovary syndrome. During the long-term Darwinian evolution, difficulties in childbirth evolved due to a narrowed pelvis, our upright walking and enlarged fetal brain sizes. Because there are 1.5% genomic DNA differences between woman and man, it is of significance to investigate sex-specific human physiology and diseases. In conclusion, understanding out of step adaptation during evolution could allow the prevention and better management of female reproductive dysfunction and diseases.

Abdominal adipose tissue and liver fat imaging in very low birth weight adults born preterm: birth cohort with sibling-controls

Preterm birth at very low birth weight (VLBW, < 1500 g) is associated with an accumulation of cardiovascular and metabolic risk factors from childhood at least to middle age. Small-scale studies suggest that this could partly be explained by increased visceral or ectopic fat. We performed magnetic resonance imaging on 78 adults born preterm at VLBW in Finland between 1978 and 1990 and 72 term same-sex siblings as controls, with a mean age of 29 years. We collected T1-weighted images from the abdomen, and magnetic resonance spectra from the liver, subcutaneous abdominal adipose tissue, and tibia. The adipose tissue volumes of VLBW adults did not differ from their term siblings when adjusting for age, sex, and maternal and perinatal factors. The mean differences were as follows: subcutaneous − 0.48% (95% CI − 14.8%, 16.3%), visceral 7.96% (95% CI − 10.4%, 30.1%), and total abdominal fat quantity 1.05% (95% CI − 13.7%, 18.4%). Hepatic triglyceride content was also similar. VLBW individuals displayed less unsaturation in subcutaneous adipose tissue (− 4.74%, 95% CI − 9.2%, − 0.1%) but not in tibial bone marrow (1.68%, 95% CI − 1.86%, 5.35%). VLBW adults displayed similar adipose tissue volumes and hepatic triglyceride content as their term siblings. Previously reported differences could thus partly be due to genetic or environmental characteristics shared between siblings. The VLBW group displayed less unsaturation in subcutaneous abdominal adipose tissue, suggesting differences in its metabolic activity and energy storage.

Influence of adipose tissue immune dysfunction on childhood obesity

In recent decades, a dramatic rise has been observed in the prevalence of obesity in childhood and adolescence, along with an increase in fetal microsomia rates. The increased risk of obesity during this key period in development negatively affects the health of the individual later in life. Immune cells residing and recruited to white adipose tissue have been highlighted as important factors contributing to the pathogenesis of childhood obesity. Immune dysfunction in the context of obesity begins early in childhood, which is different from the pathological characteristics and influencing factors of adipose immunity in adults. Here, we explore the current understanding of the roles of childhood and early life events that result in high risks for obesity by influencing adipose tissue immune dysfunction under the pathological condition of obesity. Such knowledge will help in determining the mechanisms of childhood and early life obesity in efforts to ameliorate chronic inflammation-related metabolic diseases.

Neonatal and Preterm Infant Growth Assessment

The needs to assess preterm infant growth clinically differ from the needs to summarize growth for research. Clinically, growth assessments are used to understand individuals' growth relative to their individual genetic potential, morbidity status and nutrition care. Growth quantification for research purposes is used to quantify growth of groups using meaningful metrics. Historically, neonatology has lacked consistency in the use of growth metrics, over-used irrelevant categories and over-diagnosed growth failure. Understanding the numerous preterm infant expected growth patterns can help identify concerning growth.

Body Composition Assessment by Air-Displacement Plethysmography Compared to Dual-Energy X-ray Absorptiometry in Full-Term and Preterm Aged Three to Five Years

It is important to monitor body composition longitudinally, especially in children with atypical body composition trajectories. Dual-energy X-ray absorptiometry (DXA) can be used and reference values are available. Air-displacement plethysmography (ADP) is a relatively new technique, but reference values are lacking. In addition, estimates of fat-free mass density (Dffm), needed in ADP calculations, are based on children aged >8 years and may not be valid for younger children. We, therefore, aimed to investigate whether DXA and ADP results were comparable in young children aged 3−5 years, either born full-term or preterm, and if Dffm estimates in the ADP algorithm could be improved. In 154 healthy children born full-term and 67 born < 30 weeks of the inverse pressure-volume gestation, aged 3−5 years, body composition was measured using ADP (BODPOD, with default Lohman Dffm estimates) and DXA (Lunar Prodigy). We compared fat mass (FM), fat mass percentage (FM%) and fat-free mass (FFM), between ADP and DXA using Bland−Altman analyses, in both groups. Using a 3-compartment model as reference method, we revised the Dffm estimates for ADP. In full-term-born children, Bland−Altman analyses showed considerable fixed and proportional bias for FM, FM%, and FFM. After revising the Dffm estimates, agreement between ADP and DXA improved, with mean differences (LoA) for FM, FM%, and FFM of −0.67 kg (−2.38; 1.04), −3.54% (−13.44; 6.36), and 0.5 kg (−1.30; 2.30), respectively, but a small fixed and proportional bias remained. The differences between ADP and DXA were larger in preterm-born children, even after revising Dffm estimates. So, despite revised and improved sex and age-specific Dffm estimates, results of ADP and DXA remained not comparable and should not be used interchangeably in the longitudinal assessment of body composition in children aged 3−5 years, and especially not in very preterm-born children of that age.

Timing of Adiposity Rebound and Determinants of Early Adiposity Rebound in Korean Infants and Children Based on Data from the National Health Insurance Service

Adiposity rebound (AR) is defined as the second rise in the body mass index (BMI) usually occurring in early childhood. This study aimed to investigate the timing of AR and the factors determining early AR (EAR) by tracking BMI patterns using large-scale longitudinal nationwide data (n = 142,668; 73,389 boys and 69,279 girls) over seven time periods (4–6, 9–12, 18–24, 30–36, 42–48, 54–60, and 66–71 months). The average BMI rebound indicating AR was found before the age of 5 years (6th time period, 54–60 months). Interestingly, children experiencing BMI rebound during the 4th to 6th time periods showed a small increase in the proportion of underweight in the 2nd time period, but a dramatically higher proportion of underweight during the corresponding time period, similar to M-shaped patterns. In contrast, overweight or obese children in the above group showed opposite W-shaped patterns. The parameters predicting the risk of EAR are diverse for each time period by sex. Adequate breastfeeding before the age of 1 year, adequate diet, and reduced sugar-sweetened beverage consumption after the age of 1 year were important for reducing EAR. This study presents for the first time, the timing of AR and the major determinants of EAR among Korean infants and children based on large-scale nationwide data.

A systematic review indicates an association between birth weight and body fat in childhood

AIM

To summarise the existing evidence regarding the body fat of small or large for gestation subjects, evaluated from birth up to 18 years of age.

METHODS

The PRISMA guidelines were adopted for the current systematic review, including studies having evaluated body fat with bioelectrical impedance analysis, air displacement plethysmography, dual-energy X-ray absorptiometry or magnetic resonance imaging.

RESULTS

A total of 31 studies was included. The balance of evidence suggests that small for gestation infants have decreased fat mass at birth; postnatally they experience increased adiposity. In the long term, however, the evidence is inconclusive, since some studies suggest that foetal-restricted children with increased catch-up growth are at increased risk of fat accumulation, whereas other studies suggest a neutral or even negative association. Large for gestation infants have increased fat mass at birth, but in the long term, they have a lower body fat ratio, especially when they develop a catch-down growth.

CONCLUSION

Some studies suggested that foetal-restricted children with increased catch-up growth are at increased risk of later adiposity, while other studies suggested a neutral or negative association. Given that the evidence is inconclusive, further studies are warranted. Large for gestation subjects have lower body fat when they develop catch-down growth.

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.

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

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

The association of prenatal exposure to particulate matter with infant growth: A birth cohort study in Beijing, China

Limited studies examined the associations of prenatal exposure to particulate matter (PM) and children's growth with inconsistent results, and no study focused on PM₁. We matched a birth cohort (10,547 children) with daily PM₁ and PM_2.5 concentrations by maternal home addresses. Air pollution concentrations were predicted by satellite remote sensing data, meteorological factors, and land use information. The weight and length of children in the birth cohort were measured at approximately one year old. We calculated the Z-score of weight for length (WFL) and body mass index (BMI) and then defined overweight and obesity (OWOB) based on WHO Standards. Generalized linear regression and modified Poisson regression were used to identify the association of prenatal exposure to PM₁ or PM_2.5 with anthropometric measurements and risk of OWOB. We also determined the mediation effect of preterm birth on the associations. Results showed that a 10 μg/m³ increase in prenatal exposure to PM₁ and PM_2.5 was significantly associated with a 0.105 [95% confidence interval (CI): 0.067, 0.144] and 0.063 (95% CI: 0.029, 0.097) increase in WFL Z-score for one-year-old children. Similar associations were found for BMI Z-score. A 10 μg/m³ increase in prenatal PM₁ and PM_2.5 exposure was significantly associated with 1.012 (95%CI: 1.003, 1.021) and 1.010 (95%CI: 1.002, 1.018) times higher risk of OWOB. . Preterm birth mediated 7.5% [direct effect (DE) = 0.106, P < 0.001; indirect effect (IE) = 0.009, P < 0.001)] and 9.9% (DE = 0.064, P < 0.001; IE = 0.007, P < 0.001) of the association between prenatal PM₁ and PM_2.5 exposure and WFL Z-score of the children. The association of prenatal PM₁ and PM_2.5 exposure with BMI Z-score of children was also mediated by preterm birth by 6.6% (DE = 0.111, P < 0.001; IE = 0.008, P < 0.001) and 9.1% (DE = 0.064, P < 0.001; IE = 0.006, P < 0.001). These results remained robust in the sensitivity analyses. In conclusion, prenatal exposure to PM₁ and PM_2.5 increased WFL, BMI Z-scores and higher risk of OWOB for one-year-old children. The associations were partially mediated by preterm birth. These findings call for the urgent action on air pollution regulation to protect early-life health among children.

Weight for length measures may not accurately reflect adiposity in preterm infants born appropriate for gestational age during hospitalisation or after discharge from the neonatal intensive care unit

BACKGROUND

Weight/length (W/L) indices are poor surrogates for adiposity in preterm infants born appropriate for gestational age (AGA) at birth, but whether the association subsequently improves is unknown.

OBJECTIVE

To determine if W/L indices accurately reflect adiposity in premature infants born AGA in later infancy.

METHODS

Associations between W/L indices and fat mass, fat mass index and percent body fat (%BF) obtained via air displacement plethysmography (ADP) were examined in 260 preterm infants (majority born AGA) at 28 to 63 weeks' postmenstrual age (PMA). Accuracy of W/L indices as indicators of adiposity was assessed by proportion of variance explained (R² ) and root mean square error from linear regression of adiposity on W/L indices and proportion of infants misclassified by W/L indices. Accuracy was further compared in term vs preterm infants at term-equivalent age. The impact of early vs late preterm status on associations between W/L indices and %BF was also examined.

RESULTS

BMI and W/L were most strongly associated with %BF but yielded poorly fitting models (maximum R² = 0.35; 53% misclassification). A significant interaction of W/L indices and early vs late preterm status on %BF revealed that estimation of %BF differs by status. Accuracy of W/L indices was worse in preterm infants at term-equivalent age.

CONCLUSIONS

W/L indices were not good indicators of adiposity in preterm infants from 28 to 63 weeks' PMA (born AGA) with all categories of W/L indices combined. Future research should examine whether results are similar in preterm infants born with disproportionate W/L or who experience disproportionate growth postnatally.

Adipose Tissue Development and Expansion from the Womb to Adolescence: An Overview

Prevalence rates of pediatric obesity continue to rise worldwide. Adipose tissue (AT) development and expansion initiate in the fetus and extend throughout the lifespan. This paper presents an overview of the AT developmental trajectories from the intrauterine period to adolescence; factors determining adiposity expansion are also discussed. The greatest fetal increases in AT were observed in the third pregnancy trimester, with growing evidence suggesting that maternal health and nutrition, toxin exposure, and genetic defects impact AT development. From birth up to six months, healthy term newborns experience steep increases in AT; but a subsequent reduction in AT is observed during infancy. Important determinants of AT in infancy identified in this review included feeding practices and factors shaping the gut microbiome. Low AT accrual rates are maintained up to puberty onset, at which time, the pattern of adiposity expansion becomes sex dependent. As girls experience rapid increases and boys experience decreases in AT, sexual dimorphism in hormone secretion can be considered the main contributor for changes. Eating patterns/behaviors and interactions between dietary components, gut microbiome, and immune cells also influence AT expansion. Despite the plasticity of this tissue, substantial evidence supports that adiposity at birth and infancy highly influences its levels across subsequent life stages. Thus, a unique window of opportunity for the prevention and/or slowing down of the predisposition toward obesity, exists from pregnancy through childhood.

Higher versus lower protein intake in formula-fed low birth weight infants

BACKGROUND

The ideal quantity of dietary protein for formula-fed low birth weight infants is still a matter of debate. Protein intake must be sufficient to achieve normal growth without leading to negative effects such as acidosis, uremia, and elevated levels of circulating amino acids.

OBJECTIVES

To determine whether higher (≥ 3.0 g/kg/d) versus lower (< 3.0 g/kg/d) protein intake during the initial hospital stay of formula-fed preterm infants or low birth weight infants (< 2.5 kilograms) results in improved growth and neurodevelopmental outcomes without evidence of short- or long-term morbidity. Specific objectives were to examine the following comparisons of interventions and to conduct subgroup analyses if possible. 1. Low protein intake if the amount was less than 3.0 g/kg/d. 2. High protein intake if the amount was equal to or greater than 3.0 g/kg/d but less than 4.0 g/kg/d. 3. Very high protein intake if the amount was equal to or greater than 4.0 g/kg/d.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 8), in the Cochrane Library (August 2, 2019); OVID MEDLINE Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily, and Ovid MEDLINE(R) (to August 2, 2019); MEDLINE via PubMed (to August 2, 2019) for the previous year; and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (to August 2, 2019). We also searched clinical trials databases and the reference lists of retrieved articles for randomized controlled trials (RCTs) and quasi-randomized trials.

SELECTION CRITERIA

We included RCTs contrasting levels of formula protein intake as low (< 3.0 g/kg/d), high (≥ 3.0 g/kg/d but < 4.0 g/kg/d), or very high (≥ 4.0 g/kg/d) in formula-fed hospitalized neonates weighing less than 2.5 kilograms. We excluded studies if infants received partial parenteral nutrition during the study period, or if infants were fed formula as a supplement to human milk.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane and the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We identified six eligible trials that enrolled 218 infants through searches updated to August 2, 2019. Five studies compared low (< 3 g/kg/d) versus high (3.0 to 4.0 g/kg/d) protein intake using formulas that kept other nutrients constant. The trials were small (n = 139), and almost all had methodological limitations; the most frequent uncertainty was about attrition. Low-certainty evidence suggests improved weight gain (mean difference [MD] 2.36 g/kg/d, 95% confidence interval [CI] 1.31 to 3.40) and higher nitrogen accretion in infants receiving formula with higher protein content (3.0 to 4.0 g/kg/d) versus lower protein content (< 3 g/kg/d), while other nutrients were kept constant. No significant differences were seen in rates of necrotizing enterocolitis, sepsis, or diarrhea. We are uncertain whether high versus low protein intake affects head growth (MD 0.37 cm/week, 95% CI 0.16 to 0.58; n = 18) and length gain (MD 0.16 cm/week, 95% CI -0.02 to 0.34; n = 48), but sample sizes were small for these comparisons. One study compared high (3.0 to 4.0 g/kg/d) versus very high (≥ 4 g/kg/d) protein intake (average intakes were 3.6 and 4.1 g/kg/d) during and after an initial hospital stay (n = 77). Moderate-certainty evidence shows no significant differences in weight gain or length gain to discharge, term, and 12 weeks corrected age from very high protein intake (4.1 versus 3.6 g/kg/d). Three of the 24 infants receiving very high protein intake developed uremia.

AUTHORS' CONCLUSIONS

Higher protein intake (≥ 3.0 g/kg/d but < 4.0 g/kg/d) from formula accelerates weight gain. However, limited information is available regarding the impact of higher formula protein intake on long-term outcomes such as neurodevelopment. Research is needed to investigate the safety and effectiveness of protein intake ≥ 4.0 g/kg/d.

NICU Diet, Physical Growth and Nutrient Accretion, and Preterm Infant Brain Development

Half of very preterm infants experience neurodevelopmental impairments after NICU discharge. These adverse outcomes result in part from abnormal brain development and injury that occur during the NICU hospitalization. Although many factors influence infant brain development, nutritional determinants are of particular interest because they are highly modifiable within clinical care. Physical growth of preterm infants in the NICU continues to lag behind the reference fetus, suggesting reduced nutrient accretion during a critical period for brain development. Nutrient accretion is driven by intake of specific nutrients such as macro- and micronutrients as well as non-nutritional factors such as systemic inflammation. Most often, anthropometric indicators, such as weight, length, and head circumference, are used as proxies for nutrient accretion. A limitation of weight is that it does not differentiate the healthy growth of specific organs and tissues from excess fat accumulation. Body length provides information about skeletal growth, and linear growth stunting predicts neurodevelopmental impairment. Head circumference is only a crude proxy for brain size. More recently, application of new technologies such as air displacement plethysmography and magnetic resonance imaging has allowed the direct estimation of lean tissue accretion and brain growth in the NICU. These newer techniques can facilitate research to improve our understanding of the links among the NICU diet, inflammation, physical growth, and brain development. These new measures may also be relevant within clinical care to identify infants who may benefit from specific interventions to enhance nutrient accretion and brain development.

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.

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.

Premature small for gestational age infants fed an exclusive human milk-based diet achieve catch-up growth without metabolic consequences at 2 years of age

OBJECTIVE

To compare postdischarge growth, adiposity and metabolic outcomes of appropriate for gestational age (AGA) versus small for gestational age (SGA) premature infants fed an exclusive human milk (HM)-based diet in the neonatal intensive care unit.

DESIGN

Premature infants (birth weight ≤1250 g) fed an exclusive HM-based diet were examined at 12-15 months corrected gestational age (CGA) (visit 1) for anthropometrics, serum glucose and non-fasting insulin, and at 18-22 months CGA (visit 2) for body composition by dual-energy X-ray absorptiometry.

RESULTS

Of 51 children, 33 were AGA and 18 were SGA at birth. The SGA group had weight gain (g/day) equal to AGA group during the follow-up period. SGA had a significantly greater body mass index (BMI) z-score gain from visit 1 to visit 2 (0.25±1.10 vs -0.21±0.84, p=0.02) reflecting catch-up growth. There were no significant differences in total fat mass (FM) and trunk FM between groups. SGA had significantly lower insulin level (5.0±3.7 vs 17.3±15.1 µU/mL, p=0.02) and homeostatic model of assessment-insulin resistance (1.1±0.9 vs 4.3±4.1, p=0.02). Although regional trunk FM correlated with insulin levels in SGA (r=0.893, p=0.04), they had lower insulin level compared with AGA and no difference in adiposity.

CONCLUSIONS

SGA premature infants who received an exclusive HM-based diet exhibited greater catch-up growth without increased adiposity or elevated insulin resistance compared with AGA at 2 years of age. An exclusive HM-based diet may improve long-term body composition and metabolic outcomes of premature infants with ≤1250 g birth weight, specifically SGA.

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.

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.

The impact of intrauterine and extrauterine weight gain in premature infants on later body composition

BackgroundThe impact of intrauterine and extrauterine growth on later insulin resistance and fat mass (FM) in very low birth weight (VLBW) infants is not well established. The aim of our study was to evaluate the effects of intrauterine and early/late extrauterine growth on later insulin resistance and body composition in VLBW infants from 6 months' corrected age (CA) to 36 months.MethodsProspective measurements of body composition by dual-energy X-ray absorptiometry and insulin resistance by homeostasis model assessment insulin resistance (HOMA-IR) along with other fasting plasma biochemistries were made in 95 VLBW infants at 6, 12, 18, and 24 months' CA and 36 months' postnatal age. Mixed-effect models were used to evaluate the effects of age, sex, maturation status, and Δweight SD score on percentage FM (PFM), FM index (FMI), fat-free mass index (FFMI), and HOMA-IR.ResultsPFM and FMI were negatively associated with a decrease in weight-SD scores from birth to 36 weeks' postmenstrual age (PMA; P=0.001) and from 36 weeks' PMA to 6 months' CA (P=0.003). PFM and FMI were higher in AGA than in small for gestational age (SGA) infants. HOMA-IR was not associated with the Δweight-SD scores in either period.ConclusionsCatch-down growth in terms of weight is associated with persistently lower adiposity but not insulin resistance up to 36 months of age.

Body Composition Trajectories From Infancy to Preschool in Children Born Premature Versus Full-term

OBJECTIVES

The aim of the study was to longitudinally characterize infancy to preschool body composition trajectories and the association of early fat and fat-free mass gains with preschool age body composition in children born premature versus full-term.

METHODS

A cohort of appropriate-for-gestational age preterm (n = 20) and term (n = 51) infants were followed at 3 visits: "neonatal" visit 1 at 2 weeks of age for term and near term corrected age for preterm; "infancy" visit 2 at 3 to 4 months (preterm corrected age); "preschool" visit 3 at 4 years. Body composition via air displacement plethysmography and anthropometrics were measured at all visits. Tracking of infancy weight and body composition with preschool measurements was tested using Pearson partial correlation coefficients. Associations between serial body composition measurements were assessed using multiple linear regression.

RESULTS

Early differences in body composition between premature (mean gestational age 31.9 weeks, mean birth weight 1843 g) and full-term (mean gestational age 39.8 weeks) infants were not present at preschool age. Visit 1 body composition was not correlated with preschool measurements in the preterm infants. Visit 2 measurements were correlated with preschool measures. Fat-free mass accretion from visit 1 to visit 2 was positively associated with preschool lean mass (β = 0.038, P = 0.049) in preterm children, whereas fat accretion was not associated with preschool body composition.

CONCLUSIONS

Children born prematurely and full-term have similar body composition at preschool age. For preterms infancy fat-free mass gains, and not adiposity gains, are positively associated with preschool fat-free mass; this may be associated with lower risk of later obesity and adverse metabolic outcomes.

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

BACKGROUND

The identification of factors involved in the postnatal growth of preterm infants will help achieve growth similar to that of term infants.

OBJECTIVES

As per protocol: to compare body composition in very preterm infants at term-corrected age (TCA) with that in term infants, and to explore relationships between neonatal characteristics and body composition in preterm infants.

METHODS

Anthropometry, nutritional characteristics, and neonatal outcomes were prospectively collected in 26 preterm (<29 weeks) and 33 term (37-40 weeks) infants. Body composition using dual-energy X-ray absorptiometry (DXA) was measured at TCA in preterm infants and between days 7 and 10 in term infants.

RESULTS

Parenteral nutrition in preterm infants provided a mean of 2.9 ± 0.2 and 2.1 ± 0.5 g/kg/day of intravenous amino acids and lipids, respectively, during the first week of life. The mean weight gain velocity from birth to DXA assessment was 12.1 ± 1.4 g/kg/day. Compared with term infants, preterm infants at TCA were shorter and lighter, with a smaller head circumference, a lower weight estimated by DXA (2,960 ± 552 vs. 3,843 ± 377 g), and increased skinfold thicknesses. Fat mass percent (13.9 ± 5.4%) and lean mass percent (84.7 ± 5.6%) in preterm infants were similar to those in term infants (14.7 ± 3.5 and 83.5 ± 3.6%, respectively). Neonatal weight gain velocity in preterm infants was positively associated with lean mass (grams).

CONCLUSION

Subcutaneous fat is increased in preterm infants. Higher protein intake in preterm infants might increase weight gain velocity and achieve a lean mass comparable to that of term infants.

Prevalence of diabetes and obesity in association with prematurity and growth restriction

Intrauterine growth restriction (IUGR) is when fetuses and newborn infants have not reached their true growth potential as genetically defined. Fetuses with IUGR develop in a less than ideal environment that leads to epigenetic changes and marks infants' metabolism for the rest of their lives. Epigenetic changes affect insulin-like growth factor-1 (IGF-1) levels and lead to insulin resistance and ultimately to a metabolic syndrome. The metabolic syndrome is a constellation of illnesses that raise one's risk for type 2 diabetes mellitus, coronary artery disease, and ischemic heart disease, including hypertension, dyslipidemia, central obesity, insulin resistance, and inflammation. The association between IUGR or prematurity and long-term insulin resistance, obesity, hypertension, and metabolic syndrome remains unclear. While studies have shown an association, others have not supported such association. If alteration of intrauterine growth can ultimately lead to the development of metabolic derangements in childhood and adulthood, and if such association is true, then early interventions targeting the health of pregnant women will ensure the health of the population to follow.

Importance of gut microbiota in health and diseases of new born infants

The multifarious assortment of microorganisms present in gut of humans is termed as gut microbiota. These include 1,000 species accompanied by approximately 2 million genes in an individual adult. The gut microbiota has multifactorial protective roles against allergic reactions, inflammation, cardiac pathological states and even in the state of malignant carcinogenesis existing in humans. By contrast, adverse alterations in the microbiota result in chronic pathological states, including autoimmune diseases, cancer and circulatory system obstructions. Gut bacteria also maintain sensitivity towards nutritional changes as well as antibiotics. The present review article focused on the importance of gut bacteria in newborn infants with special reference to their protective role in various pediatric pathological states linked with gut bacteria. In addition, the importance of probiotics in relation to gut microbiota are to be discussed.

Greater Early Gains in Fat-Free Mass, but Not Fat Mass, Are Associated with Improved Neurodevelopment at 1 Year Corrected Age for Prematurity in Very Low Birth Weight Preterm Infants

OBJECTIVE

This work investigates the relationship between early body composition changes and neurodevelopment at 1 year age corrected for prematurity (CA).

STUDY DESIGN

A prospective, longitudinal study to measure body composition weekly in 34 very low birth weight preterm infants using air displacement plethysmography, beginning when infants stabilized after birth until discharge. Neurodevelopmental testing (Bayley Scales of Infant Development-III) was performed at 12 months CA. Linear mixed effects models were used to obtain inpatient subject-specific changes in fat-free mass (FFM) and fat mass (FM), which were then used as predictors of Bayley subscale scores in subsequent linear regression models, adjusting for potential confounders. Protein and energy provision were calculated for the first week of life.

RESULTS

Greater FFM gains while inpatient were associated with improved cognitive and motor scores at 12 months CA (P = .002 for both). These relationships remained significant when adjusting for birth weight, gestational age, and intraventricular hemorrhage (P ≤ .05 for both). Similar analysis was performed for FM gains without significant findings. Increased provision of protein and calories during the first week of life was positively associated with FFM gains (P ≤ .01 for both), but not FM gains (P ≥ .2 for both), throughout hospitalization.

CONCLUSIONS

Increased FFM gains, but not FM gains, during hospitalization are associated with improved neurodevelopment at 12 months CA. As early FM gains may be associated with long-term risk, more research is needed to develop strategies that optimize FFM gains while minimizing FM gains in very low birth weight preterm infants.

Effects of postnatal growth restriction and subsequent catch-up growth on neurodevelopment and glucose homeostasis in rats

Background

There is increasing evidence that poor growth of preterm infants is a risk factor for poor long-term development, while the effects of early postnatal growth restriction are not well known. We utilized a rat model to examine the consequences of different patterns of postnatal growth and hypothesized that early growth failure leads to impaired development and insulin resistance. Rat pups were separated at birth into normal (N, n = 10) or restricted intake (R, n = 16) litters. At d11, R pups were re-randomized into litters of 6 (R-6), 10 (R-10) or 16 (R-16) pups/dam. N pups remained in litters of 10 pups/dam (N-10). Memory and learning were examined through T-maze test. Insulin sensitivity was measured by i.p. insulin tolerance test and glucose tolerance test.

Results

By d10, N pups weighed 20 % more than R pups (p < 0.001). By d15, the R-6 group caught up to the N-10 group in weight, the R-10 group showed partial catch-up growth and the R-16 group showed no catch-up growth. All R groups showed poorer scores in developmental testing when compared with the N-10 group during T-Maze test (p < 0.05). Although R-16 were more insulin sensitive than R-6 and R-10, all R groups were more glucose tolerant than N-10.

Conclusion

In rats, differences in postnatal growth restriction leads to changes in development and in insulin sensitivity. These results may contribute to better elucidating the causes of poor developmental outcomes in human preterm infants.

Nutritional strategy of early amino acid administration in very low birth weight infants

Relative to a fetus of the same gestational age, very low birth weight (VLBW) infants are more likely to be underfed and to undergo growth restriction during their early hospital stay. The current trend towards "early and aggressive" nutritional strategies in VLBW infants aims to overcome the early nutritional deficiency and thereby boost postnatal catch-up growth, simultaneously improving long-term neurodevelopmental outcomes. Although the minimum starting amino acid (AA) dose to prevent negative nitrogen balance is well established, the upper limit and the rate of increase of early AA doses are controversial. Most randomized controlled trials show that early and high-dose (target, 3.5 to 4.9 g/kg/day) AA regimens, with or without high nonprotein calories, do not improve long-term growth and neurodevelopment. High-dose AA supplementation may lead to early metabolic disturbances and excessive or disproportionate plasma AA levels, particularly in infants of very low gestational age. Further large studies are needed to clarify the optimal strategy for early administration of parenteral AA doses in VLBW infants.

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.

Lean mass and fat mass accretion between term age and 6 months post-term in growth-restricted preterm infants

Early growth restriction followed by nutritional intakes that permit accelerated growth may result in adiposity and metabolic disease in later life. This study compared growth, body composition and nutritional intake between term age and 6 months post-term in 83 appropriate-for-gestational-age preterm infants with growth restriction at term age (AGA GR+), 15 AGA without growth restriction at term age (AGA GR-) and 33 small-for-gestational-age (SGA) preterm infants. AGA GR+ and SGA preterm infants had higher protein intake, higher energy intake and higher gain in weight SDS between term age and 6 months post-term, with similar lean mass (LM) and lower fat mass (FM) at 6 months post-term compared with AGA GR- preterm infants. In conclusion, despite higher energy and protein intake compared with AGA GR- preterm infants during the first 6 months post-term, AGA GR+ and SGA preterm infants restore their LM without excessive FM.

Body composition in late preterm infants in the first 10 days of life and at full term

AIM

To investigate changes in body weight, fat-free mass, fat mass and percentage of body fat during early life and at full-term postconceptional age (PCA) in preterm infants born after 32 gestational weeks and before 37.

METHODS

Twenty-nine late preterm infants underwent growth and body composition assessment by air displacement plethysmography (ADP) at the age of 4 days and at full-term PCA. In 25 of these infants, body composition was assessed three times between days four and nine of life. The preterm infants were compared with 29 full-term infants, matched for gestational age, sex and body weight.

RESULTS

There was a significant increase in birth weight and fat-free mass between days four and nine of life. Preterm infants had significantly more body fat 382 ± 180 g vs 287 ± 160 g than full-term infants at full-term PCA. Preterm infants showed poor linear growth between birth and full-term PCA.

CONCLUSION

Weight gain after the initial postnatal weight loss consists of gain in fat-free mass. At full-term PCA, preterm infants were stunted. When compared with full-term new born infants matched for body weight and gestational age, preterm infants had more body fat and a higher percentage of body fat.

Assessment of neonatal growth in prematurely born infants

The concept that adequate nutritional status and normal growth are important is well-accepted. How to assess the adequacy of nutrition and how to define appropriate growth remains an area of active debate. Our goal is to review how growth is assessed at birth and during the hospital stay of prematurely born infants, and to offer a standardized approach.

Higher protein intake improves length, not weight, z scores in preterm infants

OBJECTIVE

The aim of the study was to evaluate the relation between nutritional intake (kilocalories, protein) and weight and length growth in preterm infants, and to describe their metabolic tolerance with a focus on those with high protein intake (≥ 4.6 g · kg(-1) · day(-1)).

METHODS

Secondary analysis of data from appropriate-for-gestational age preterm infants in a 28-day randomized clinical trial that evaluated growth, tolerance, and safety of a new ultraconcentrated liquid human milk fortifier (original study n = 150). This subset of 56 infants had complete growth and nutrition data and met criteria for the original study's "efficacy analysis" (eg, >80% of kilocalorie intake from study diet). Nutritional intake was estimated, not actual. Regressions were used to test cumulative kilocalories and protein as the predictors of 28-day change in weight and length z scores (growth status), and to evaluate protein tolerance.

RESULTS

Average intake was 118 ± 8 kcal · kg(-1) · day(-1) and 4.3 ± 0.4 g protein · kg(-1) · day(-1), with 16 ± 3 g · kg(-1) · day(-1) and 1.1 ± 0.2 cm/week growth for 28 days. Cumulative total kilocalories and protein were significant predictors of improved length z score (P = 0.0054, 0.0005) but not weight z score change. Regression models indicated that protein not kilocalories explained the improvement in length z score, with protein explaining 19% of the variability. The high protein group averaged 4.6 to 5.5 g · kg(-1) · day(-1) (n = 16). Protein tolerance was adequate for all of the study infants based on metabolic measures (blood urea nitrogen, serum carbon dioxide, pH).

CONCLUSIONS

Higher cumulative protein intake was tolerated and overall lessened the commonly occurring decline in the length but not weight growth status in a 28-day study of preterm infants.

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.

Does low birth weight predict hypertension and obesity in schoolchildren?

BACKGROUND

Birth weight appears to play a role in determining high blood pressure (BP) and obesity during childhood. The purpose of this study is to investigate the association between birth weight and later obesity and hypertension among 10- to 13-year-old schoolchildren.

METHODS

A total of 1,184 primary school students were selected from 20 randomized schools between 2011 and 2012 in Iran. Height, weight, waist circumference and BP were measured using standard instruments. Data were analyzed using stepwise regression and logistic regression models.

RESULTS

13.5% of children had a history of low birth weight. First-degree family history of obesity, excessive gestational weight gain and birth weight were significantly correlated with overweight/obesity and abdominal obesity (p = 0.001), whereas only birth weight was associated with high BP (p = 0.001). An inverse correlation was found between waist circumference and systolic/diastolic BP. The duration of breastfeeding in children with low birth weight was inversely correlated with obesity/overweight, abdominal obesity and hypertension.

CONCLUSION

The results suggests that birth weight is inversely associated with BP and more so with obesity and abdominal obesity. The duration of having been breastfed could have an influence on later hypertension, obesity and abdominal obesity. Further results are needed to test these correlations as well as diagnosing early life factors to prevent young adult overweight/obesity or hypertension.

Feeding preterm infants today for later metabolic and cardiovascular outcomes

Preterm birth continues to contribute disproportionately to neonatal morbidity and subsequent physical and neurodevelopmental disabilities. Epidemiologic studies have described additional long-term health consequences of preterm birth such as an increased risk of hypertension and insulin resistance in adult life. It is not known whether the influence of infant and childhood growth rates and early nutrition on long-term outcomes is the same or different among preterm infants and neonates with intrauterine growth restriction. Our goal is to review the effects of fetal growth, postnatal growth, and early nutrition on long-term cardiovascular and metabolic outcomes in preterm infants. Present evidence suggests that even brief periods of relative undernutrition during a sensitive period of development have significant adverse effects on later development. Our review suggests that growth between birth and expected term and 12-18 months post-term has no significant effect on later blood pressure and metabolic syndrome, whereas reduced growth during hospitalization significantly impacts later neurodevelopment. In contrast, growth during late infancy and childhood appears to be a major determinant of later metabolic and cardiovascular well being, which suggests that nutritional interventions during this period are worthy of more study. Our review also highlights the paucity of well-designed, controlled studies in preterm infants of the effects of nutrition during hospitalization and after discharge on development, the risk of developing hypertension, or insulin resistance.

Tactile/kinesthetic stimulation (TKS) increases tibial speed of sound and urinary osteocalcin (U-MidOC and unOC) in premature infants (29-32weeks PMA)

Preterm delivery (<37 weeks post-menstrual age) is associated with suboptimal bone mass. We hypothesized that tactile/kinesthetic stimulation (TKS), a form of infant massage that incorporates kinesthetic movement, would increase bone strength and markers of bone accretion in preterm infants. Preterm, AGA infants (29-32 weeks) were randomly assigned to TKS (N=20) or Control (N=20). Twice daily TKS was provided 6 days per week for 2 weeks. Control infants received the same care without TKS treatment. Treatment was masked to parents, health care providers, and study personnel. Baseline and week two measures were collected for tibial speed of sound (tSOS, m/sec), a surrogate for bone strength, by quantitative ultrasound (Sunlight8000) and urine markers of bone metabolism, pyridinium crosslinks and osteocalcin (U-MidOC and unOC). Infant characteristics at birth and study entry as well as energy/nutrient intake were similar between TKS and Control. TKS intervention attenuated the decrease in tSOS observed in Control infants (p<0.05). Urinary pyridinium crosslinks decreased over time in both TKS and CTL (p<0.005). TKS infants experienced greater increases in urinary osteocalcin (U-MidOC, p<0.001 and unOC, p<0.05). We conclude that TKS improves bone strength in premature infants by attenuating the decrease that normally follows preterm birth. Further, biomarkers of bone metabolism suggest a modification in bone turnover in TKS infants in favor of bone accretion. Taken together, we speculate that TKS improves bone mineralization.