Air displacement plethysmography (pea pod) in full-term and pre-term infants: a comprehensive review of accuracy, reproducibility, and practical challenges

Evaluation of Maternal Factors Affecting Postpartum Insulin Resistance Markers in Mothers with Gestational Diabetes-A Case-Control Study

BACKGROUND

Gestational diabetes mellitus (GDM) is defined by an insufficient insulin response to counteract the insulin resistance (IR) that arises from the physiological adaptations associated with pregnancy. However, the pathophysiology of IR is complex and unclear, as it encompasses elements such as epigenetics, environmental factors, modifiable lifestyle factors, and psychosocial factors.

AIM

The objective of this study was to evaluate the influence of GDM and other maternal factors on IR markers in comparison to mothers with normal glucose tolerance during pregnancy in the first week postpartum.

MATERIAL AND METHODS

The study population comprised 70 participants, including mothers with gestational diabetes who were treated with a diet and physical activity (GDM G1), with insulin (GDM G2), and a control group of healthy mothers without gestational diabetes (non-GDM). A series of statistical techniques were employed to facilitate the comparison of data between the study groups, with the objective of identifying potential associations with maternal factors. A taxonomic analysis was conducted using the following factors: classification by study group, a history of hypothyroidism in the maternal medical interview, and maternal gestational weight gain, which were identified as the best-fitting predictors.

RESULTS

The analysis resulted in the identification of four clusters of patients. Comparison of the insulin resistance markers between mothers assigned to the abovementioned clusters showed differences in the incidence of excessive weight loss and in the results of glucose screening tests during pregnancy. Also, differences concerning fasting glucose levels in the first and second/third trimesters of pregnancy and glucose levels at 1 h post-OGTT were found. For the clusters, the results of the HOMA-IR and the QUICKI did not show any differences in the first week after delivery (p > 0.05). HbA1c results varied significantly.

CONCLUSIONS

Degree of glucose metabolism disorders, hypothyroidism, and weight gain in pregnancy influence maternal insulin resistance markers in the first week postpartum. Additionally, gestational weight fluctuation has a significant influence on the outcome of pregnancy, particularly with regard to fetal growth and, consequently, the infant's birth weight and adipose tissue accumulation.

Body composition assessment in 6-month-old infants: A comparison of two- and three-compartment models using data from the Baby-bod study

BACKGROUND/OBJECTIVES

An appreciation of infant body composition is helpful to understand the 'quality' of growth in early life. Air displacement plethysmography (ADP) using PEA POD and the deuterium dilution (DD) technique are commonly used body composition approaches in infants. We evaluated the comparability of body composition assessed using both techniques with two-compartment (2C) and three-compartment (3C) models in 6-month-old infants.

SUBJECTS/METHODS

Infant fat mass (FM) and percent fat mass (%FM) obtained from a 2C model using PEA POD (2C-PP) and a 2C model using the deuterium dilution technique (2C-DD) were compared to those derived from a 3C model, and to each other, using Bland-Altman analysis and Deming regression.

RESULTS

Measurements were available from 68 infants (93% Caucasian, 53% male). The mean biases were not significant between any of the method comparisons. However, significant constant and proportional biases were identified in 2C-DD vs 3C and 2C-PP vs 2C-DD, but not in the 2C-PP vs 3C comparison. Furthermore, we observed significant associations between the mean differences and infants' percent total body water (%TBW).

CONCLUSIONS

While no significant between-method mean differences were found in body composition estimates, some comparisons revealed significant constant and proportional biases and notable associations between the mean differences and %TBW were observed. Our results emphasise the importance of method choice, ensuring methodological uniformity in long-term studies, and carefully considering and regulating multiple pre-analytical variables, such as the hydration status of the participants.

Kisspeptin signalling and its correlation with placental ultrastructure and clinical outcomes in pregnant South African women with obesity and gestational diabetes

INTRODUCTION

Gestational diabetes mellitus (GDM) is a major pregnancy metabolic disorder and is strongly linked with obesity. Kisspeptin is a hormone that increases several thousand-fold in the maternal circulation during human pregnancy, with placenta as its main source. Studies have suggested that kisspeptin regulates trophoblast invasion and promotes pancreatic insulin secretion and peripheral insulin sensitivity.

METHODS

In a well-characterized cohort of pregnant South African women and molecular and histological techniques, this study explored the impact and interaction of maternal obesity and GDM on kisspeptin (KISS1) signalling in relation to placental morphology and maternal and neonatal parameters.

RESULTS

We found that GDM had no effect on placental KISS1 and KISS1R (KISS1 receptor) mRNA and/or protein expression. However, obesity reduced placental KISS1R mRNA expression even though overall KISS1 protein abundance or localization was not different from the non-obese group. Maternal and cord circulating KISS1 concentrations did not vary with obesity or GDM, but maternal circulating KISS1 was positively correlated with placenta weight in non-GDM obese women, and negatively correlated with placental intervillous space volume in non-GDM non-obese women. Cord serum KISS1 was positively correlated with infant weight in GDM obese women, but negatively correlated with maternal BMI in the non-obese GDM group. Placental syncytiotrophoblast extracellular vesicles exhibited detectable KISS1 and its abundance was ∼50 % lower in those from obese GDM compared to non-GDM women.

DISCUSSION

This study shows maternal obesity and GDM can modulate placental kisspeptin signalling and placental morphological development with potential pathophysiological implications for clinically-relevant pregnancy and perinatal outcomes.

Body Composition Analysis of the Clinical Routine Using Air Displacement Plethysmography: Age-Group-Specific Feasibility Analysis among Preterm Infants

Body composition assessments using air displacement plethysmography (ADP, PEAPOD®) have been introduced into clinical practice at a few neonatal units. To allow accurate body composition assessments in term and preterm infants, a workflow for routine testing is needed. The aim of this study was to analyze the feasibility of weekly routine ADP testing. We analyzed (1) postnatal ages at first ADP assessment, (2) the number of weekly routine in-hospital assessments, and (3) the workload of body composition measurements using ADP in clinical practice on the basis of an retrospective analysis of our own clinical operating procedures. The retrospective analysis of weekly routine ADP testing proved feasible at Nuremberg Children's Hospital. The analysis of postnatal age at the first ADP test revealed differences across groups, with extremely preterm infants starting at a mean postmenstrual age of 36.6 weeks, very preterm infants starting at 34.2 weeks, and moderate to late preterm infants starting at 35.3 weeks. The mean number of tests before discharge was significantly greater in the extremely preterm group (n = 3.0) than in the very preterm (n = 2.4) and moderate to late preterm groups (n = 1.7). The workload of the procedure is reasonable, at 8-13 min per test cycle. The study proved that weekly routine ADP assessments in preterm infants are feasible. However, the initiation of routine testing in extremely preterm infants starts at a significantly greater postnatal age than in the more mature population. ADP assessments can be safely and easily integrated into clinical practice and may be valuable tools for providing additional information on nutritional status and infant growth. A standardized routine protocol allowing identical measurement conditions across healthcare institutions and a standardized interpretation tool for age-adapted body composition data, however, would improve comparability and usability.

Adult obesity diagnostic tool: A narrative review

Obesity is a complex chronic metabolic disorder characterized by abnormalities in lipid metabolism. Obesity is not only associated with various chronic diseases but also has negative effects on physiological functions such as the cardiovascular, endocrine and immune systems. As a global health problem, the incidence and prevalence of obesity have increased significantly in recent years. Therefore, understanding assessment methods and measurement indicators for obesity is critical for early screening and effective disease control. Current methods for measuring obesity in adult include density calculation, anthropometric measurements, bioelectrical impedance analysis, dual-energy X-ray absorptiometry, computerized imaging, etc. Measurement indicators mainly include weight, hip circumference, waist circumference, neck circumference, skinfold thickness, etc. This paper provides a comprehensive review of the literature to date, summarizes and analyzes various assessment methods and measurement indicators for adult obesity, and provides insights and guidance for the innovation of obesity assessment indicators.

Impact of Gestational Diabetes Detection Thresholds on Infant Growth and Body Composition: A Prospective Cohort Study Within a Randomized Trial

OBJECTIVE

Gestational diabetes mellitus (GDM) is associated with offspring metabolic disease, including childhood obesity, but causal mediators remain to be established. We assessed the impact of lower versus higher thresholds for detection and treatment of GDM on infant risk factors for obesity, including body composition, growth, nutrition, and appetite.

RESEARCH DESIGN AND METHODS

In this prospective cohort study within the Gestational Diabetes Mellitus Trial of Diagnostic Detection Thresholds (GEMS), pregnant women were randomly allocated to detection of GDM using the lower criteria of the International Association of Diabetes and Pregnancy Study Groups or higher New Zealand criteria (ACTRN12615000290594). Randomly selected control infants of women without GDM were compared with infants exposed to A) GDM by lower but not higher criteria, with usual treatment for diabetes in pregnancy; B) GDM by lower but not higher criteria, untreated; or C) GDM by higher criteria, treated. The primary outcome was whole-body fat mass at 5-6 months.

RESULTS

There were 760 infants enrolled, and 432 were assessed for the primary outcome. Fat mass was not significantly different between control infants (2.05 kg) and exposure groups: A) GDM by lower but not higher criteria, treated (1.96 kg), adjusted mean difference (aMD) -0.09 (95% CI -0.29, 0.10); B) GDM by lower but not higher criteria, untreated (1.94 kg), aMD -0.15 (95% CI -0.35, 0.06); and C) GDM detected and treated using higher thresholds (1.87 kg), aMD -0.17 (95% CI -0.37, 0.03).

CONCLUSIONS

GDM detected using lower but not higher criteria, was not associated with increased infant fat mass at 5-6 months, regardless of maternal treatment. GDM detected and treated using higher thresholds was also not associated with increased fat mass at 5-6 months.

Associations of weight and body composition at birth with body composition and cardiometabolic markers in children aged 10 y: the Ethiopian infant anthropometry and body composition birth cohort study

BACKGROUND

Although birth weight (BW) has been associated with later cardiovascular disease and type 2 diabetes, the role of birth fat mass (BFM) and birth fat-free mass (BFFM) on cardiometabolic health is unclear.

OBJECTIVES

To examine associations of BW, BFM, and BFFM with later anthropometry, body composition, abdominal fat, and cardiometabolic markers.

METHODS

Birth cohort data on standardized exposure variables (BW, BFM, and BFFM) and follow-up information at age 10 y on anthropometry, body composition, abdominal fat, and cardiometabolic markers were included. A linear regression analysis was used to assess associations of exposures with outcome variables, adjusting for maternal and child characteristics at birth and current body size in separate models.

RESULTS

Among 353 children, mean (SD) age was 9.8 (1.0) y, and 51.5% were boys. In the fully adjusted model, 1-SD higher BW and BFFM were associated with 0.81 cm (95% CI: 0.21, 1.41 cm) and 1.25 cm (95% CI: 0.64, 1.85 cm) greater height at 10 y, respectively. The 1-SD higher BW and BFM were associated with 0.32 kg/m2 (95% CI: 0.14, 0.51 kg/m2) and 0.42 kg/m2 (95% CI: 0.25, 0.59 kg/m2) greater fat mass index at 10 y, respectively. In addition, 1-SD higher BW and BFFM were associated with 0.22 kg/m2 (95% CI: 0.09, 0.34 kg/m2) greater FFM index, whereas a 1-SD greater BFM was associated with a 0.05 cm greater subcutaneous adipose tissue (95% CI: 0.01, 0.11 cm). Furthermore, 1-SD higher BW and BFFM were associated with 10.3% (95% CI: 1.4%, 20.0%) and 8.3% (95% CI: -0.5%, 17.9%) greater insulin, respectively. Similarly, 1-SD higher BW and BFFM were associated with 10.0% (95% CI: 0.9%, 20.0%) and 8.5% (95% CI: -0.6%, 18.5%) greater homeostasis model assessment of insulin resistance, respectively.

CONCLUSIONS

BW and BFFM rather than BFM are predictors of height and FFM index at 10 y. Children with higher BW and BFFM showed higher insulin concentrations and homeostasis model assessment of insulin resistance at 10 y of age. This trial was registered at ISRCTN as ISRCTN46718296.

Integrated growth assessment in the first 1000 d of life: an interdisciplinary conceptual framework

OBJECTIVES

Prenatal growth affects short- and long-term morbidity, mortality and growth, yet communication between prenatal and postnatal healthcare teams is often minimal. This paper aims to develop an integrated, interdisciplinary framework for foetal/infant growth assessment, contributing to the continuity of care across the first 1000 d of life.

DESIGN

A multidisciplinary think-tank met regularly over many months to share and debate their practice and research experience related to foetal/infant growth assessment. Participants’ personal practice and knowledge were verified against and supplemented by published research.

SETTING

Online and in-person brainstorming sessions of growth assessment practices that are feasible and valuable in resource-limited, low- and middle-income country (LMIC) settings.

PARTICIPANTS

A group of obstetricians, paediatricians, dietitians/nutritionists and a statistician.

RESULTS

Numerous measurements, indices and indicators were identified for growth assessment in the first 1000 d. Relationships between foetal, neonatal and infant measurements were elucidated and integrated into an interdisciplinary framework. Practices relevant to LMIC were then highlighted: antenatal Doppler screening, comprehensive and accurate birth anthropometry (including proportionality of weight, length and head circumference), placenta weighing and incorporation of length-for-age, weight-for-length and mid-upper arm circumference in routine growth monitoring. The need for appropriate, standardised clinical records and corresponding policies to guide clinical practice and facilitate interdisciplinary communication over time became apparent.

CONCLUSIONS

Clearer communication between prenatal, perinatal and postnatal health care providers, within the framework of a common understanding of growth assessment and a supportive policy environment, is a prerequisite to continuity of care and optimal health and development outcomes.

Body composition reference charts for infants from birth to 24 months: Multicenter Infant Body Composition Reference Study

BACKGROUND

Body composition assessment in the first 2 y of life provides important insights into child nutrition and health. The application and interpretation of body composition data in infants and young children have been challenged by a lack of global reference data.

OBJECTIVES

We aimed to develop body composition reference charts of infants aged 0-6 mo based on air displacement plethysmography (ADP) and those aged 3-24 mo based on total body water (TBW) by deuterium dilution (DD).

METHODS

Body composition was assessed by ADP in infants aged 0-6 mo from Australia, India, and South Africa. TBW using DD was assessed for infants aged 3-24 mo from Brazil, Pakistan, South Africa, and Sri Lanka. Reference charts and centiles were constructed for body composition using the lambda-mu-sigma method.

RESULTS

Sex-specific reference charts were produced for FM index (FMI), FFM index (FFMI), and percent FM (%FM) for infants aged 0-6 mo (n = 470 infants; 1899 observations) and 3-24 mo (n = 1026 infants; 3690 observations). When compared with other available references, there were observable differences but similar patterns in the trajectories of FMI, FFMI, and %FM.

CONCLUSIONS

These reference charts will strengthen the interpretation and understanding of body composition in infants across the first 24 mo of life.

Targeting Sarcopenia as an Objective Clinical Outcome in the Care of Children with Spinal Cord-Related Paralysis: A Clinician's View

Muscle loss is consistently associated with immobility and paralysis and triggers significant metabolic and functional changes. The negative effects of sarcopenia are amplified in children who are in the process of building their muscle mass as part of development. Because muscle mass loss is consistently associated with increased morbidity and mortality throughout life, optimizing the size and health of muscles following a neurologic injury is an objective target for therapeutic interventions. This review hypothesizes that muscle mass correlates with functional outcomes in children with paralysis related to spinal cord-related neurologic deficits. We propose that the measurement of muscle mass in this population can be used as an objective outcome for clinical long-term care. Finally, some practical clinical approaches to improving muscle mass are presented.

Body composition in preterm infants: a systematic review on measurement methods

BACKGROUND

There are several methods to measure body composition in preterm infants. Yet, there is no agreement on which method should be preferred.

METHODS

PubMed, Embase.com, Wiley/Cochrane Library, and Google Scholar were searched for studies that reported on the predictive value or validity of body composition measurements in preterms, up to 6 months corrected age.

RESULTS

Nineteen out of 1884 identified studies were included. Predictive equations based on weight and length indices, body area circumferences, skinfold thickness, bioelectrical impedance, and ultrasound did not show agreement with body composition measured with air displacement plethysmography (ADP), dual-energy x-ray absorptiometry (DXA), magnetic resonance imaging (MRI), or isotope dilution. ADP agreed well with fat mass density measured by isotope dilution (bias -0.002 g/ml, limits of agreement ±0.012 g/ml, n = 14). Fat mass percentage measured with ADP did not agree well with fat mass percentage measured by isotope dilution (limits of agreement up to ±5.8%) and the bias between measurements was up to 2.2%. DXA, MRI, and isotope dilution were not compared to another reference method in preterms.

CONCLUSIONS

DXA, ADP, and isotope dilution methods are considered trustworthy validated techniques. Nevertheless, this review showed that these methods may not yield comparable results.

IMPACT

Based on validation studies that were conducted in a limited number of study subjects, weight and length indices, body area circumferences, skinfold thickness, bioelectrical impedance, and ultrasound seem to be a poor representation of body composition in preterm infants. DXA, ADP, and isotope dilution methods are considered trustworthy and validated techniques. Nevertheless, these methods may not yield comparable results.

The Impacts of Single Preterm Human Donor Milk Compared to Mother's Own Milk on Growth and Body Composition

(1) If mother´s own milk (MOM) is not available, pooled term human donor milk (HDM) is commonly used. Compared to MOM, term HDM contains less protein and fat and is associated with impaired growth. HDM from mothers of preterm infants is an alternative source and contains higher protein levels compared to term HDM, but the impacts on growth and body composition are unclear. (2) Methods: Infants born below 32 weeks of gestation and below 1500 g between 2017-2022, who underwent air displacement plethysmography (Pea Pod^®) to determine body composition (FFM: fat-free mass; FM: fat mass) at term-equivalent age, were included. A comparison between infants fed with MOM > 50% (MOM-group) and single preterm HDM > 50% (HDM-group) was conducted. (3) Results: In total, 351 infants (MOM-group: n = 206; HDM-group: n = 145) were included for the analysis. The median FFM-Z-score (MOM-group: -1.09; IQR: -2.02, 1.11; HDM-group: -1.13; IQR: -2.03, 1.12; p = 0.96), FM-Z-score (MOM-group: 1.06; IQR: -0.08, 2.22; HDM-group: 1.19; IQR: -0.14, 2.20; p = 0.09), and median growth velocity (MOM-group: 23.1 g/kg/d; IQR: 20.7, 26.0; HDM: 22.5 g/kg/d; IQR: 19.7, 25.8; p = 0.15) values were not significantly different between the groups. (4) Conclusion: Single preterm HDM is a good alternative to support normal growth and body composition.

Association of Prenatal Placental Function with Anthropometry and Body Composition through 2 years of Age in South African Infants: The UmbiBaby Study

BACKGROUND

Placental insufficiency negatively impacts fetal growth and body composition (BC), potentially affecting lifelong health. Placental insufficiency, detectable as an abnormal umbilical artery resistance index (UmA-RI) on Doppler ultrasonography, is highly prevalent in otherwise healthy South African pregnant women. Appropriate intervention reduces stillbirth and perinatal death, but research on long-term outcomes of surviving infants is lacking.

OBJECTIVES

To describe and compare anthropometry and BC during the first 2 y of life in a cohort of term-born infants with normal and abnormal prenatal UmA-RI.

METHODS

Term-born infants (n = 81; n = 55 normal, n = 26 abnormal UmA-RI on third trimester Doppler screening) were followed up at 8-time points until age 2 y. Anthropometric measurements were taken, and FFM and FM were assessed by deuterium dilution. Age- and sex-specific z-scores were calculated for anthropometric indices, FM, FFM, FM index (FMI), and FFM index (FFMI) using appropriate reference data. Anthropometry and BC of infants with normal and abnormal UmA-RI were compared using an independent t-test or Mann-Whitney test.

RESULTS

At most ages, group mean z-scores were <0 for length-for-age and FM and >0 for weight-for-length and FFM. Compared with infants with normal UmA-RI, infants with abnormal UmA-RI had significantly lower weight-for-age z-scores at birth (-0.77 ± 0.75 compared with -0.30 ± 1.10, P = 0.026), ages 10 wk to 9 mo (-0.4 ± 0.87 to -0.2 ± 1.12 compared with 0.3 ± 0.85 to 0.6 ± 1.09; P = 0.007-0.017) and 18 mo (-0.6 ± 0.82 compared with 0.1 ± 1.18; P = 0.037); length-for-age z-scores at ages ≤14 wk (-1.3 ± 1.25 to -0.9 ± 0.87 compared with -0.2 ± 1.04 to -0.1 ± 1.00; P = 0.004-0.021); and FFM-for-age z-scores at ages ≤9 mo (-0.1 ± 0.82 to 0.7 ± 0.71 compared with 0.7 ± 1.00 to 1.3 ± 0.85; P = 0.002-0.028). FFMI, percentage FFM, FM, percentage FM, and FMI showed no consistent significant differences.

CONCLUSIONS

Infants with abnormal UmA-RI had lower weight-for-age and length-for-age z-scores, particularly at younger ages, with proportionally lower FFM but no consistent differences in percentage FFM and FFMI. These findings merit further investigation in larger cohorts. J Nutr 2023;xx:xx-xx.

Growth and body composition trajectories in infants meeting the WHO growth standards study requirements

BACKGROUND

While the World Health Organization (WHO) developed postnatal growth standards for infants, corresponding body composition data remains scarce. This study explores growth and body composition trajectories in infants meeting the WHO Multicentre Growth Reference Study (MGRS) eligibility criteria.

STUDY DESIGN

Infants enrolled in this longitudinal cohort underwent anthropometric and body composition measurement by air displacement plethysmography (ADP) at 6 weeks, 12 weeks, and 5 months postnatally. Age and sex-specific growth and body composition percentiles were generated using GAMLSS, with extrapolated data at 5 months for those exceeding ADP weight limits. We evaluated which anthropometric measure (body mass index (BMI), weight for length or mid upper arm circumference) was most closely related to adiposity.

RESULTS

Of the 225 infants with body composition measures, 187 met the WHO MGRS criteria. Their length and weight curves were comparable with WHO growth curves. Trajectory curves for fat and fat-free mass were developed. Of the anthropometric measures, BMI z score was most closely related to fat mass index z score at all timepoints.

CONCLUSION

This study presents body composition trajectories for infants meeting the WHO growth standard criteria. BMI z score is the best anthropometric metric to estimate adiposity in infants.

IMPACT

While postnatal growth standards derived from the WHO Multicentre Growth Reference Study (MGRS) exist for the routine clinical assessment of infant growth, this study fills the previous gap in the availability of corresponding body composition data for term-born, healthy, breastfed infants meeting the MGRS criteria. Extrapolation was used to obtain body composition values for infants exceeding the weight limit of the ADP device, to avoid construction of biased body composition curves. Sex-specific growth curves for fat mass, fat-free mass, fat mass index, and fat-free mass index are presented for a population meeting the World Health Organization growth standard criteria.

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

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

Prediction of fat-free mass in a multi-ethnic cohort of infants using bioelectrical impedance: Validation against the PEA POD

Background

Bioelectrical impedance analysis (BIA) is widely used to measure body composition but has not been adequately evaluated in infancy. Prior studies have largely been of poor quality, and few included healthy term-born offspring, so it is unclear if BIA can accurately predict body composition at this age.

Aim

This study evaluated impedance technology to predict fat-free mass (FFM) among a large multi-ethnic cohort of infants from the United Kingdom, Singapore, and New Zealand at ages 6 weeks and 6 months (n = 292 and 212, respectively).

Materials and methods

Using air displacement plethysmography (PEA POD) as the reference, two impedance approaches were evaluated: (1) empirical prediction equations; (2) Cole modeling and mixture theory prediction. Sex-specific equations were developed among ∼70% of the cohort. Equations were validated in the remaining ∼30% and in an independent University of Queensland cohort. Mixture theory estimates of FFM were validated using the entire cohort at both ages.

Results

Sex-specific equations based on weight and length explained 75-81% of FFM variance at 6 weeks but only 48-57% at 6 months. At both ages, the margin of error for these equations was 5-6% of mean FFM, as assessed by the root mean squared errors (RMSE). The stepwise addition of clinically-relevant covariates (i.e., gestational age, birthweight SDS, subscapular skinfold thickness, abdominal circumference) improved model accuracy (i.e., lowered RMSE). However, improvements in model accuracy were not consistently observed when impedance parameters (as the impedance index) were incorporated instead of length. The bioimpedance equations had mean absolute percentage errors (MAPE) < 5% when validated. Limits of agreement analyses showed that biases were low (< 100 g) and limits of agreement were narrower for bioimpedance-based than anthropometry-based equations, with no clear benefit following the addition of clinically-relevant variables. Estimates of FFM from BIS mixture theory prediction were inaccurate (MAPE 11-12%).

Conclusion

The addition of the impedance index improved the accuracy of empirical FFM predictions. However, improvements were modest, so the benefits of using bioimpedance in the field remain unclear and require further investigation. Mixture theory prediction of FFM from BIS is inaccurate in infancy and cannot be recommended.

Preterm birth and metabolic implications on later life: A narrative review focused on body composition

Preterm newborn infants are characterized by low body weight and lower fat mass at birth compared with full-term newborn neonates. Conversely, at term corrected age, body fat mass is more represented in preterm newborn infants, causing a predisposition to developing metabolic syndrome and cardiovascular diseases in later life with a different risk profile in men as compared with women. Postnatal growth is a complex change in anthropometric parameters and body composition. Both quantity and quality of growth are regulated by several factors such as fetal programming, early nutrition, and gut microbiota. Weight gain alone is not an optimal indicator of nutritional status as it does not accurately describe weight quality. The analysis of body composition represents a potentially useful tool to predict later metabolic and cardiovascular risk as it detects the quality of growth by differentiating between fat and lean mass. Longitudinal follow-up of preterm newborn infants could take advantage of body composition analysis in order to identify high-risk patients who apply early preventive strategies. This narrative review aimed to examine the state-of-the-art body composition among born preterm children, with a focus on those in the pre-school age group.

Prenatal exposure to tobacco and adverse birth outcomes: effect modification by folate intake during pregnancy

BACKGROUND

Fetal exposure to tobacco increases the risk for many adverse birth outcomes, but whether diet mitigates these risks has yet to be explored. Here, we examined whether maternal folate intake (from foods and supplements) during pregnancy modified the association between prenatal exposure to tobacco and with preterm delivery, small-for-gestational age (SGA) births, or neonatal adiposity.

METHODS

Mother-child pairs (n = 701) from Healthy Start were included in this analysis. Urinary cotinine was measured at ~ 27 weeks gestation. Diet was assessed using repeated 24-h dietary recalls. Neonatal adiposity (fat mass percentage) was measured via air displacement plethysmography. Interaction was assessed by including a product term between cotinine (< / ≥ limit of detection [LOD]) and folate (< / ≥ 25th percentile [1077 µg/day]) in separate logistic or linear regression models, adjusting for maternal age, race, ethnicity, education, pre-pregnancy body mass index, and infant sex.

RESULTS

Approximately 26% of women had detectable levels of cotinine. Folate intake was significantly lower among women with cotinine ≥ LOD as compared to those with cotinine < LOD (1293 µg/day vs. 1418 µg/day; p = 0.01). Folate modified the association between fetal exposure to tobacco with neonatal adiposity (p for interaction = 0.07) and SGA (p for interaction = 0.07). Among those with lower folate intake, fetal exposure to tobacco was associated with lower neonatal adiposity (mean difference: -2.09%; 95% CI: -3.44, -0.74) and increased SGA risk (OR: 4.99; 95% CI: 1.55, 16.14). Conversely, among those with higher folate intake, there was no difference in neonatal adiposity (mean difference: -0.17%; 95% CI: -1.13, 0.79) or SGA risk (OR: 1.15; 95% CI: 0.57, 2.31).

CONCLUSIONS

Increased folate intake during pregnancy (from foods and/or supplements) may mitigate the risk of fetal growth restriction among those who are unable to quit smoking or cannot avoid secondhand smoke during pregnancy.

Valuing the Diversity of Research Methods to Advance Nutrition Science

The ASN Board of Directors appointed the Nutrition Research Task Force to develop a report on scientific methods used in nutrition science to advance discovery, interpretation, and application of knowledge in the field. The genesis of this report was growing concern about the tone of discourse among nutrition professionals and the implications of acrimony on the productive study and translation of nutrition science. Too often, honest differences of opinion are cast as conflicts instead of areas of needed collaboration. Recognition of the value (and limitations) of contributions from well-executed nutrition science derived from the various approaches used in the discipline, as well as appreciation of how their layering will yield the strongest evidence base, will provide a basis for greater productivity and impact. Greater collaborative efforts within the field of nutrition science will require an understanding that each method or approach has a place and function that should be valued and used together to create the nutrition evidence base. Precision nutrition was identified as an important emerging nutrition topic by the preponderance of task force members, and this theme was adopted for the report because it lent itself to integration of many approaches in nutrition science. Although the primary audience for this report is nutrition researchers and other nutrition professionals, a secondary aim is to develop a document useful for the various audiences that translate nutrition research, including journalists, clinicians, and policymakers. The intent is to promote accurate, transparent, verifiable evidence-based communication about nutrition science. This will facilitate reasoned interpretation and application of emerging findings and, thereby, improve understanding and trust in nutrition science and appropriate characterization, development, and adoption of recommendations.

Body composition correlates with laboratory parameters and disease severity in infants with biliary atresia

AIM

Infants with biliary atresia (BA) generally have chronic malnutrition. However, the best anthropometric measure to assess malnutrition and its correlation with disease severity is unknown. We aimed to assess correlations of various anthropometric measurements, including air displacement plethysmography (ADP), with laboratory parameters and with the pediatric end-stage liver disease (PELD) score in infants with BA.

METHODS

Infants with BA were followed at a pediatric liver transplantation center during 2014-2018. Follow-up comprised laboratory tests and nutritional assessment by a dietitian including dietary intake, weight, height, mid-upper arm circumference (MUAC), and skin-fold thickness. Fat-free mass (FFM) and fat mass (FM) were measured by ADP.

RESULTS

Forty-three nutritional evaluations were performed in 28 infants with BA (13 boys, 44.4%). The median age was 20.7 weeks (IQR: 13-25.9). Based on the various anthropometry modalities, infants with BA were found to be malnourished on most of the visits; 63% had a MUAC-Z score lower than -2 standard deviations. High serum bilirubin level predicted lower weight for age, length for age, and MUAC-Z. Lower MUAC-Z was associated with a higher PELD score. Neither FM mass nor FFM correlated with PELD or with serum bilirubin level. However, FM correlated with skin-fold thickness-Z and was low in most patients.

CONCLUSIONS

The majority of BA infants suffer from malnutrition as assessed by most anthropometrics modalities; low MUAC correlated best with disease severity and serum bilirubin level. Further studies are warranted to determine the contribution of FM measurement by ADP to the anthropometric assessment of infants with BA.

Sarcopenia in Children with Solid Organ Tumors: An Instrumental Era

Sarcopenia has recently been studied in both adults and children and was found to be a prognostic marker for adverse outcome in a variety of patient groups. Our research showed that sarcopenia is a relevant marker in predicting outcome in children with solid organ tumors, such as hepatoblastoma and neuroblastoma. This was especially true in very ill, high-risk groups. Children with cancer have a higher likelihood of ongoing loss of skeletal muscle mass due to a mismatch in energy intake and expenditure. Additionally, the effects of cancer therapy, hormonal alterations, chronic inflammation, multi-organ dysfunction, and a hypermetabolic state all contribute to a loss of skeletal muscle mass. Sarcopenia seems to be able to pinpoint this waste to a high degree in a new and objective way, making it an additional tool in predicting and improving outcome in children. This article focuses on the current state of sarcopenia in children with solid organ tumors. It details the pathophysiological mechanisms behind sarcopenia, highlighting the technical features of the available methods for measuring muscle mass, strength, and function, including artificial intelligence (AI)-based techniques. It also reviews the latest research on sarcopenia in children, focusing on children with solid organ tumors.

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.

Anthropometrics and fat mass, but not fat-free mass, are compromised in infants requiring parenteral nutrition after neonatal intestinal surgery

BACKGROUND

Children with intestinal failure (IF) receiving long-term parenteral nutrition (PN) have altered body composition (BC), but data on BC changes from start of PN onwards are lacking.

OBJECTIVES

We aimed to assess growth and BC in infants after neonatal intestinal surgery necessitating PN and at risk of IF, and to explore associations with clinical parameters.

METHODS

A prospective cohort study in infants after intestinal surgery. IF was defined as PN dependency for >60 d. SD scores (SDS) for anthropometry were calculated until 6-mo corrected age. In a subgroup, fat mass (FM) and fat-free mass (FFM) were measured with air-displacement plethysmography at 2- and 6-mo corrected age. SDS for length-adjusted FM index and FFM index were calculated. Associations between cumulative amount of PN and BC parameters were analyzed with linear mixed-effect models.

RESULTS

Ninety-five neonates were included (54% male, 35% born <32 wk) and 39 infants (41%) had IF. Studied infants had compromised anthropometric parameters during follow-up. At 6-mo corrected age, they remained smaller (median weight-for-age SDS -0.9 [IQR -1.5, 0.1], P < 0.001) than the normal population. In 57 infants, 93 BC measurements were performed. FM index SDS was lower than in healthy infants at 2- and 6-mo corrected age (-0.9 [-1.6, -0.3], P < 0.001 and -0.7 [-1.3, 0.1], P = 0.001, respectively), but FFM index SDS did not differ. A higher cumulative amount of PN predicted a higher FM index in female infants but lower FM index in male infants.

CONCLUSIONS

In this cohort of infants receiving PN after intestinal surgery, compromised anthropometrics, decreased FM, and adequate FFM were observed during the first 6 mo. Male and female infants seemed to respond differently to PN when it comes to FM index. Continuing growth monitoring after the age of 6 mo is strongly recommended, and further research should explore the benefit of incorporating ongoing BC monitoring during follow-up.

Body composition and bone mineral density by Dual Energy X-ray Absorptiometry: Reference values for young children

BACKGROUND & AIMS

Childhood obesity is a global public health threat, with an alarming rise in incidence. Obesity at young age has short-term and long-term morbidity. It is, therefore, important to accurately assess body composition throughout infancy and childhood to identify excess adiposity. However, reference values for age 2-5 years, needed to interpret measurements and identify young children at risk, are lacking. Our primary objective was to fill the current gap in reference values by constructing sex-specific body composition reference values and charts for fat mass (FM), fat mass percentage (FM%), fat mass index (FMI), lean body mass (LBM), lean body mass index (LBMI) and total body less head bone mineral density (BMD_TBLH) for children aged 2-5 years using Dual-Energy X-ray Absorptiometry (DXA).

METHODS

We performed 599 accurate DXA-measurements in 340 term-born children aged 2-5 years, using Lunar Prodigy with Encore software (V14.1). Using GAMLSS, sex-specific reference values and charts were created for FM, FM%, FMI, LBM, LBMI and BMD_TBLH.

RESULTS

Sex-specific body composition reference values and charts for age 2-5 years were constructed. In boys and girls, FM and LBM increased from age 2-5 years (all p ≤ 0.001), but body size-corrected FM% and FMI decreased (all p ≤ 0.023). LBMI remained similar between 2 and 5 years of age. Girls had higher FM, FM% and FMI and lower LBM and LBMI compared to boys. BMC and BMD_TBLH increased with age between 2 and 5 years of age (all p < 0.001) and were similar for boys and girls.

CONCLUSIONS

We present sex-specific reference values and charts for body composition and total body bone mineral density measured by DXA, based on a large cohort of healthy children aged 2-5 years. These longitudinal references can be used for clinical practice and research purposes to monitor body composition and bone mineral density development and identify children at risk for excess adiposity.

A Life Course Approach to the Relationship Between Fetal Growth and Hypothalamic-Pituitary-Adrenal Axis Function

CONTEXT

Human and animal studies suggest that hypothalamic-pituitary-adrenal axis (HPA-A) function may be programmed in utero; however, these findings are inconsistent. Given the powerful metabolic actions of cortisol, it is important to clarify the influence of early life on adult HPA-A function.

OBJECTIVE

To determine the relationship between fetal growth and HPA-A stress response to a psychosocial stressor in young adults.

DESIGN

Multigenerational, prospective cohort study (the Raine Study) conducted between 1989 and 1991.

SETTING

King Edward Memorial Hospital, Perth, Western Australia, Australia.

PARTICIPANTS

A total of 917 participants aged 18 years from Gen2 of the Raine Study.

MAIN OUTCOME MEASURES

Measures of hypothalamic-pituitary-adrenal axis function before and after exposure to the Trier Social Stress Test.

RESULTS

In fully adjusted models, an inverse linear relationship was observed between birthweight and plasma measures of (1) baseline cortisol (β = -0.90%, 95% CI: -1.73 to -0.07; P = 0.03); (2) peak cortisol (β = -0.78%, 95% CI -1.51 to -0.06; P = 0.03); (3) area under the curve with respect to ground (β = -0.89%, 95% CI -1.60 to -0.18; P = 0.01); and (4) adrenal sensitivity (β = -1.02, 95% CI: -1.85 to -0.18; P = 0.02). Similar results were demonstrated for percent optimal birthweight. No consistent quadratic relationships were identified. No associations were found between measures of fetal adiposity and HPA-A function at age 18 years, or fetal growth and HPA-A response pattern. Removal of anticipatory responders from the models substantially attenuated the observed relationships.

CONCLUSION

We observed an inverse linear relationship between fetal growth and HPA-A function at age 18 years. This differs from the inverse parabolic relationship (inverted U curve) reported in adults of advanced age. Altered adrenal sensitivity may underlie this relationship.

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.

Do Lifestyle Interventions in Pregnant Women with Overweight or Obesity Have an Effect on Neonatal Adiposity? A Systematic Review with Meta-Analysis

Excessive body fat at birth is a risk factor for the development of childhood obesity. The aim of the present systematic review with meta-analysis was to evaluate the effect of lifestyle interventions in pregnant women with overweight or obesity on neonatal adiposity. The PubMed, Embase, Web of Science, Scopus, and LILACS databases were used as information sources. Original articles from randomized clinical trials of lifestyle intervention studies on pregnant women with excessive body weight and the effect on neonatal adiposity were considered eligible. The risk of bias was assessed using Cochrane criteria. The meta-analysis was calculated using the inverse variance for continuous data expressed as mean difference (MD), using the random effect model with a 95% confidence interval (CI). The outcomes were submitted to the GRADE evaluation. Of 2877 studies, four were included in the qualitative and quantitative synthesis (n = 1494). All studies were conducted in developed countries, with three including pregnant women with overweight or obesity, and one only pregnant women with obesity. The interventions had no effect on neonatal adiposity [Heterogeneity = 56%, MD = −0.21, CI = (−0.92, 0.50)] with low confidence in the evidence, according to GRADE. Studies are needed in low- and medium-developed countries with different ethnic-racial populations. PROSPERO (CRD42020152489).

Infant body composition assessment in the neonatal intensive care unit (NICU) using air displacement plethysmography: Strategies for implementation into clinical workflow

Nutritional management is integral to infant care in the neonatal intensive care unit (NICU). Recent research on body composition that specifically evaluated fat and fat-free mass has improved our understanding of infant growth and nutritional requirements. The need for body composition monitoring in infants is increasingly recognized as changes in fat mass and fat-free mass associated with early growth can impact clinical outcomes. With the availability of air displacement plethysmography (ADP) as a noninvasive method for assessing infant body composition and published normative gestational age- and sex-specific body composition curves, it is justifiable to integrate this innovation into routine clinical care. Here we describe our experiences in implementing body composition measurement using ADP in routine clinical care in different NICU settings.

Determinants of Infant Adiposity across the First 6 Months of Life: Evidence from the Baby-bod study

Excess adiposity in infancy may predispose individuals to obesity later in life. The literature on determinants of adiposity in infants is equivocal. In this longitudinal cohort study, we investigated pre-pregnancy, prenatal and postnatal determinants of different adiposity indices in infants, i.e., fat mass (FM), percent FM (%FM), fat mass index (FMI) and log-log index (FM/FFM^p), from birth to 6 months, using linear mixed-effects regression. Body composition was measured in 322, 174 and 109 infants at birth and 3 and 6 months afterwards, respectively, utilising air displacement plethysmography. Positive associations were observed between gestation length and infant FM, maternal self-reported pre-pregnancy body mass index and infant %FM, and parity and infant %FM and FMI at birth. Surprisingly, maternal intake of iron supplements during pregnancy was associated with infant FM, %FM and FMI at 3 months and FM/FFM^p at 6 months. Male infant sex and formula feeding were negatively associated with all adiposity indices at 6 months. In conclusion, pre-pregnancy and pregnancy factors influence adiposity during early life, and any unfavourable impacts may be modulated postnatally via infant feeding practices. Moreover, as these associations are dependent on the adiposity indices used, it is crucial that researchers use conceptually and statistically robust approaches such as FM/FFM^p.

A comparative study using dual-energy X-ray absorptiometry, air displacement plethysmography, and skinfolds to assess fat mass in preterms at term equivalent age

The aim of this study was to compare whole body composition, generated by air displacement plethysmography (ADP) and dual-energy X-ray absorptiometry (DXA), and to evaluate the potential predictive value of the sum of skinfolds (∑SFT) for whole body composition, in preterm infants at term equivalent age. A convenience sample of sixty-five preterm infants with a mean (SD) gestational age of 29 (1.6) weeks was studied at term equivalent age. Fat mass measured by DXA and ADP were compared and the ability of the ∑SFT to predict whole body fat mass was investigated. There was poor agreement between fat mass percentage measured with ADP compared with DXA (limits of agreement: - 4.8% and 13.7%). A previously modeled predictive equation with the ∑SFT as a predictor for absolute fat mass could not be validated. Corrected for confounders, the ∑SFT explained 42% (ADP, p = 0.001) and 75% (DXA, p = 0.001) of the variance in fat mass percentage.Conclusions: The ∑SFT was not able to accurately predict fat mass and ADP and DXA did not show comparable results. It remains to be elucidated whether or not DXA provides more accurate assessment of whole body fat mass than ADP in preterm infants.Trial registration: NTR5311 What is Known: • Diverse methods are used to assess fat mass in preterm infants. What is New: • This study showed that there is poor agreement between dual-energy X-ray absorptiometry, air displacement plethysmography, and skinfold thickness measurements. • Our results affirm the need for consensus guidelines on how to measure fat mass in preterm infants, to improve the assimilation of data from different studies and the implementation of the findings from those studies.

Distinct maternal amino acids and oxylipins predict infant fat mass and fat-free mass indices

Interested in maternal determinants of infant fat mass index (FMI) and fat-free mass index (FFMI), considered as predictors for later development of obesity, we analysed amino acids (AA) and oxylipins in maternal serum and breast milk (BM). FMI and FFMI were calculated in 47 term infants aged 4 months (T4). Serum AA were analysed in pregnancy (T1, T2) and 6-8 weeks postpartum (T3). At T3, AA and oxylipins were analysed in BM. Biomarker-index-associations were identified by regression analysis. Infant FMI (4.1 ± 1.31 kg/m²; MW ± SD) was predicted by T2 proline (R² adj.: 7.6%, p = .036) and T3 BM 11-hydroxy-eicosatetraenoic-acid (11-HETE) and 13-hydroxy-docosahexaenoic-acid (13-HDHA; together:35.5% R² adj., p < .001). Maternal peripartum antibiotics (AB) emerged as confounders (+AB: 23.5% higher FMI; p = .025). Infant FFMI (12.1 ± 1.19 kg/m²; MW ± SD) was predicted by histidine (R² adj.: 14.5%, p < .001) and 17-HDHA (BM, R² adj.:19.3%, p < .001), determined at T3. Confirmed in a larger cohort, the parameters could elucidate connections between maternal metabolic status, nutrition, and infant body development.

Targeted Breast Milk Fortification for Very Low Birth Weight (VLBW) Infants: Nutritional Intake, Growth Outcome and Body Composition

Despite improvements in nutritional management, preterm infants continue to face high rates of postnatal growth restriction. Because variability in breast milk composition may result in protein and energy deficits, targeted fortification has been advocated. We conducted an interventional study to compare body composition and growth outcomes of very low birth weight infants fed targeted protein-fortified human milk (HM) with those fed standard fortified HM. If mother’s own milk was not available, donor milk was used. Weekly analysis of HM with mid-infrared spectroscopy was conducted and additional protein was added to the fortified HM to ensure a protein intake of 4 g/kg/day. Weekly anthropometric measurements were done. Prior to discharge or at 37 weeks, corrected age skinfold thickness (SFT) measurements as well as body composition measurement using air displacement plethysmography were done. Among 36 preterm infants enrolled, those in the targeted group (n = 17) received more protein and had a larger flank SFT at study end than those in the standard group (n = 19). A pilot post-hoc analysis of subjects having at least 30 intervention days showed a 3% higher fat-free mass in the targeted group. Use of a targeted fortification strategy resulted in a higher protein intake and fat-free mass among those receiving longer intervention.

Longitudinal body composition assessment in healthy term-born infants until 2 years of age using ADP and DXA with vacuum cushion

OBJECTIVES

Accelerated gain in fat mass (FM) in early life increases the risk for adult diseases. Longitudinal data on infant body composition are crucial for clinical and research use, but very difficult to obtain due to limited measurement tools and unsuccessful measurements between age 6-24 months. We compared FM% by dual-energy X-ray absorptiometry (DXA), with cushion to reduce movement artifacts, with FM% by air-displacement plethysmography (ADP) and evaluated the reliability of this cushion during DXA by comparing FM% with and without cushion. Subsequently, we constructed sex-specific longitudinal body composition charts from 1-24 months.

METHODS

In 692 healthy, term-born infants (Sophia Pluto Cohort), FM% was measured by ADP from 1-6 months and DXA with cushion from 6-24 months. At 6 months, FM% was measured in triplicate by ADP and DXA with and without cushion(n = 278), later on in smaller numbers.

RESULTS

At 6 months, mean FM% by DXA with cushion was 24.1 and by ADP 25.0, mean difference of 0.9% (Bland-Altman p = 0.321, no proportional bias). Mean FM% by DXA without cushion was 12.5% higher compared to ADP (Bland-Altman p < 0.001). DXA without cushion showed higher mean FM% compared to DXA with cushion (+11.6%, p < 0.001) at 6 months. Longitudinally, FM% increased between 1-6 months and decreased from 6-24 months(both p < 0.001).

CONCLUSIONS

In infants, DXA scan with cushion limits movement artifacts and shows reliable FM%, comparable to ADP. This allowed us to construct longitudinal body composition charts until 24 months. Our study shows that FM% increases from 1-6 months and gradually declines until 24 months.

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.

Body composition of New Zealand-born term babies differs by ethnicity, gestational age and sex

BACKGROUND

Body composition provides important information on nutrition and future metabolic risk. New Zealand has a diverse ethnic population for which there are no newborn body composition data.

AIM

To determine body composition in a cohort of New Zealand-born term babies.

STUDY DESIGN

Observational study.

SUBJECTS

Healthy, term infants between 37⁺⁰ and 41⁺⁶ weeks' gestation in two hospitals in Auckland, New Zealand.

OUTCOME MEASURES

Body composition by air displacement plethysmography and anthropometry measured within 5 days of birth. Parent-identified ethnicity was prioritised according to Ministry of Health criteria. Data were analysed using t-test, ANOVA with Tukey post-hoc tests, quantile regression and are mean(SD).

RESULTS

440 babies (54% male) were included. Pacific Island/Māori (PI/M) were heavier at birth than Asian/Middle Eastern/Latin American/African (Asian+) babies (3403(506) vs 3181(485) g, p < .05). PI/M and European (E) babies were longer with larger head and waist circumferences than Asian+ babies (all p < .05). Absolute fat mass (FM) was not different amongst ethnicities (E, 365(156), PI/M, 347(183), Asian+, 357(188) g) but PI/M babies had significantly lower FM% than Asian+ (9.8(4.3) vs 10.9(4.5) %, p < .05). Fat-free mass (FFM) was greater in PI/M (3056(400) g) than E (2952(345) g (p < .05) and both PI/M and E had greater FFM than Asian+ (2824(363) g, p < .05). Early term babies had less FFM than term and late-term babies (2732(370), 3012(352), 3173(302)g, p < .001) respectively.

CONCLUSIONS

Asian+ babies were the smallest babies with the least FFM yet had similar FM and the highest FM%, indicative of a thin, fat phenotype from birth.

Maternal sociodemographic and health behaviours associated with adiposity in infants as measured by air displacement plethysmography

BACKGROUND

Identifying modifiable factors associated with body fat in infancy may improve health outcomes. Few studies have examined factors associated with percentage body fat calculated using air displacement plethysmography, a gold standard technique.

AIMS

To investigate maternal sociodemographic and health behaviour characteristics associated with percentage body fat in offspring at birth.

STUDY DESIGN

Observational cross-sectional study in which the body composition of term infants was measured by air displacement plethysmography during the hospital stay after birth.

SUBJECTS

One-hundred-and-ninety-six women and their term (37-42 weeks) infants.

OUTCOME MEASURES

Associations between infant body composition and maternal sociodemographic and health characteristics.

RESULTS

One-hundred-and-ninety-six women (41.8% primiparous) participated. Mean percentage body fat among infants (51.5% female) was 10.3 ± 3.7. Percentage body fat was significantly (p < 0.001) higher in infants born to women with an obese or overweight body mass index (BMI), when compared to infants born to women with a healthy BMI (12.1 ± 4.0, 11.1 ± 3.1, and 9.2 ± 3.7, respectively). A significant positive correlation (r = 0.294) was observed, with the percentage body fat of infants born to women with an overweight or obese BMI being 17.1% and 23.9% higher, respectively, than that of infants born to women with a healthy weight BMI. Percentage body fat was lower in infants born to primiparous women (p = 0.011) and women of low social class (p = 0.003).

CONCLUSIONS

Infants born to women with an overweight or obese pre-pregnancy BMI had significantly higher mean percentage body fat when compared to infants born to women with a healthy pre-pregnancy BMI. Research into approaches that promote a healthy BMI in advance of pregnancy is warranted.

Low muscle mass and strength in pediatrics patients: Why should we care?

Skeletal muscle plays major roles in metabolism and overall health across the lifecycle. Emerging evidence indicates that prenatal (maternal diet during pregnancy and genetic defects) and postnatal factors (physical activity, hormones, dietary protein, and obesity) influence muscle mass acquisition and strength early in life. As a consequence, low muscle mass and strength contributes to several adverse health outcomes during childhood. Specifically, studies demonstrated inverse associations of muscle mass and strength to single and clustered metabolic risk factors. The literature also consistently reports that low muscle mass and strength are associated with reduced bone parameters during growth, increasing the risk of osteoporosis in old age. Furthermore, muscle mass gains are associated with improved neurodevelopment in the first years of life. Given these negative implications of low muscle mass and strength on health, it is crucial to track muscle mass and strength development from childhood to adolescence. Several body composition techniques are currently available for estimation of muscle mass, all with unique advantages and disadvantages. The value of ultrasound as a technique to measure muscle mass is emerging in pediatric research with potential for translating the research findings to clinical settings. For the assessment of muscle strength, the handgrip strength test has been widely employed but without a standardized protocol. Although further research is needed to define normative data and cut points for the low muscle mass and strength phenotype, the use of such non-invasive medical monitoring is a promising strategy to identify early abnormalities and prevent low muscle mass in adulthood.

Body Mass Index Is a Better Indicator of Body Composition than Weight-for-Length at Age 1 Month

OBJECTIVE

To assess whether body mass index (BMI) provides a better assessment of measured adiposity at age 1 month compared with weight-for-length (WFL).

STUDY DESIGN

Participants were healthy term-born infants in the Infant Growth and Microbiome (n = 146) and the Baby Peas (n = 147) studies. Length, weight, and body composition by air displacement plethysmography were measured at 1 month. World Health Organization-based WFL and BMI z-scores were calculated. Within-cohort z-scores of percent fat-Z, fat mass-Z, fat mass/length2-Z, fat mass/length3-Z, fat-free mass-Z, and fat-free mass/length2-Z were calculated. Correlation and multiple linear regression (adjusted for birth weight) analyses tested the associations between body composition outcomes and BMI-Z vs WFL-Z. Quantile regression was used to test the stability of these associations across the distribution of body compositions.

RESULTS

The sample was 52% female and 56% African American. Accounting for birth weight, both BMI-Z and WFL-Z were strongly associated with fat mass-Z (coefficients 0.56 and 0.35, respectively), FM/L2-Z (0.73 and 0.51), and FM/L3-Z (0.79 and 0.58), with stronger associations for BMI-Z compared with WFL-Z (P < .05). Even after accounting statistically for birth weight, BMI-Z was persistently more strongly associated than WFL-Z with body composition outcomes across the distribution of body composition outcomes.

CONCLUSIONS

We demonstrate in 2 distinct cohorts that BMI is a better indicator of adiposity in early infancy compared with WFL. Our findings support the preferred use of BMI for growth and nutritional status assessment in infancy.