Validity of Body Mass Index as a Measure of Adiposity in Infancy

Independent and joint effects of neighborhood-level environmental and socioeconomic exposures on body mass index in early childhood: The environmental influences on child health outcomes (ECHO) cohort

Past studies support the hypothesis that the prenatal period influences childhood growth. However, few studies explore the joint effects of exposures that occur simultaneously during pregnancy. To explore the feasibility of using mixtures methods with neighborhood-level environmental exposures, we assessed the effects of multiple prenatal exposures on body mass index (BMI) from birth to age 24 months. We used data from two cohorts: Healthy Start (n = 977) and Maternal and Developmental Risks from Environmental and Social Stressors (MADRES; n = 303). BMI was measured at delivery and 6, 12, and 24 months and standardized as z-scores. We included variables for air pollutants, built and natural environments, food access, and neighborhood socioeconomic status (SES). We used two complementary statistical approaches: single-exposure linear regression and quantile-based g-computation. Models were fit separately for each cohort and time point and were adjusted for relevant covariates. Single-exposure models identified negative associations between NO2 and distance to parks and positive associations between low neighborhood SES and BMI z-scores for Healthy Start participants; for MADRES participants, we observed negative associations between O3 and distance to parks and BMI z-scores. G-computations models produced comparable results for each cohort: higher exposures were generally associated with lower BMI, although results were not significant. Results from the g-computation models, which do not require a priori knowledge of the direction of associations, indicated that the direction of associations between mixture components and BMI varied by cohort and time point. Our study highlights challenges in assessing mixtures effects at the neighborhood level and in harmonizing exposure data across cohorts. For example, geospatial data of neighborhood-level exposures may not fully capture the qualities that might influence health behavior. Studies aiming to harmonize geospatial data from different geographical regions should consider contextual factors when operationalizing exposure variables.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Rapid infant weight gain or point-in-time weight status: Which is the best predictor of later obesity and body composition?

OBJECTIVE

The aim of this study was to determine which growth indicator (weight, weight-for-length, BMI) and time frame (6- or 12-month intervals between 0 and 24 months) of rapid infant weight gain (RIWG) best predicted obesity risk and body composition at 11 years of age.

METHODS

RIWG (increase ≥0.67 z scores between two time points) was calculated from weight and length/height at birth, 0.5, 1, 1.5, and 2 years. The predictive value of each measure and time frame was calculated in relation to obesity (BMI ≥95th percentile) and body fat (fat mass index [FMI], dual-energy X-ray absorptiometry scan) at 11 years.

RESULTS

The sensitivity (1.5% to 62.1%) and positive predictive value (12.5% to 33.3%) of RIWG to predict obesity varied considerably. Having obesity at any time point appeared a stronger risk factor than any indicator of RIWG for obesity at 11 years. Obesity at any age during infancy consistently predicted a greater FMI of around 1.1 to 1.5 kg/m2 at 11 years, whereas differences for RIWG were inconsistent.

CONCLUSIONS

A simple measure of obesity status at a single time point between 6 and 24 months of age appeared a stronger risk factor for later obesity and FMI than RIWG assessed by any indicator, over any time frame.

Infant body composition: A comprehensive overview of assessment techniques, nutrition factors, and health outcomes

Body composition assessment is a valuable tool for clinical assessment and research that has implications for long-term health. Unlike traditional measurements such as anthropometrics or body mass index, body composition assessments provide more accurate measures of body fatness and lean mass. Moreover, depending on the technique, they can offer insight into regional body composition, bone mineral density, and brown adipose tissue. Various methods of body composition assessment exist, including air displacement plethysmography, dual-energy x-ray absorptiometry, bioelectrical impedance, magnetic resonance imaging, D3 creatine, ultrasound, and skinfold thickness, each with its own strengths and limitations. In infants, several feeding practices and nutrition factors are associated with body composition outcomes, such as breast milk vs formula feeding, protein intake, breast milk composition, and postdischarge formulas for preterm infants. Longitudinal studies suggest that body composition in infancy predicts later body composition, obesity, and other cardiometabolic outcomes in childhood, making it a useful early marker of cardiometabolic health in both term and preterm infants. Emerging evidence also suggests that body composition during infancy predicts neurodevelopmental outcomes, particularly in preterm infants at high risk of neurodevelopmental impairment. The purpose of this narrative review is to provide clinicians and researchers with a comprehensive overview of body composition assessment techniques, summarize the links between specific nutrition practices and body composition in infancy, and describe the neurodevelopmental and cardiometabolic outcomes associated with body composition patterns in term and preterm infants.

Development and validation of anthropometric-based fat-mass prediction equations using air displacement plethysmography in Mexican infants

BACKGROUND/OBJECTIVES

Fat-mass (FM) assessment since birth using valid methodologies is crucial since excessive adiposity represents a risk factor for adverse metabolic outcomes.

AIM

To develop infant FM prediction equations using anthropometry and validate them against air-displacement plethysmography (ADP).

SUBJECTS/METHODS

Clinical, anthropometric (weight, length, body-mass index -BMI-, circumferences, and skinfolds), and FM (ADP) data were collected from healthy-term infants at 1 (n = 133), 3 (n = 105), and 6 (n = 101) months enrolled in the OBESO perinatal cohort (Mexico City). FM prediction models were developed in 3 steps: 1) Variable Selection (LASSO regression), 2) Model behavior evaluation (12-fold cross-validation, using Theil-Sen regressions), and 3) Final model evaluation (Bland-Altman plots, Deming regression).

RESULTS

Relevant variables in the FM prediction models included BMI, circumferences (waist, thigh, and calf), and skinfolds (waist, triceps, subscapular, thigh, and calf). The R2 of each model was 1 M: 0.54, 3 M: 0.69, 6 M: 0.63. Predicted FM showed high correlation values (r ≥ 0.73, p < 0.001) with FM measured with ADP. There were no significant differences between predicted vs measured FM (1 M: 0.62 vs 0.6; 3 M: 1.2 vs 1.35; 6 M: 1.65 vs 1.76 kg; p > 0.05). Bias were: 1 M -0.021 (95%CI: -0.050 to 0.008), 3 M: 0.014 (95%CI: 0.090-0.195), 6 M: 0.108 (95%CI: 0.046-0.169).

CONCLUSION

Anthropometry-based prediction equations are inexpensive and represent a more accessible method to estimate body composition. The proposed equations are useful for evaluating FM in Mexican infants.

National, longitudinal NASCITA birth cohort study: prevalence of overweight at 12 months of age in children born healthy

OBJECTIVE

To estimate the prevalence of overweight at 12 months in an Italian birth cohort and to identify factors related to an increased likelihood of being overweight.

METHODS

The Italian NASCITA birth cohort was analysed. Infants were classified as underweight (<5th), normal weight (5-84th) and overweight (≥85th centile) at 12 months of age according to the WHO percentiles of body mass index (BMI) and the prevalence of overweight was estimated. To test the association between the chance of being overweight and parental and newborn characteristics, and infant feeding, healthy newborns (no preterm/low birth weight and with no malformations), with appropriate-for-gestational-age birth weight were selected, and univariate and multivariate analyses were performed.

RESULTS

The prevalence of overweight was 23.5% (95% CI 22.2% to 24.8%) in all cohort members with 12-month data (N=4270), and 23.1% in the appropriate-for-gestational age subsample (N=2835).A big infant appetite (OR 3.92, 95% CI 2.40 to 6.40) and living in southern Italy (OR 1.58, 95% CI 1.29 to 1.94) were the main variables associated with a greater likelihood of being overweight. Breastfeeding practice did not influence the chance of being overweight, but was associated with an increase (exclusive breast feeding for at least 6 months) or a decrease (breast feeding for at least 12 months) in BMI z score at 12 months.

CONCLUSIONS

The sociodemographic factors (eg, area of residence, maternal employment status) seem to be the most relevant determinants influencing the chance of being overweight at 12 months. Early interventions, with particular attention to vulnerable families, may be helpful in preventing childhood and adult obesity.

Metagenomic analysis reveals associations between salivary microbiota and body composition in early childhood

Several studies have shown that body mass index is strongly associated with differences in gut microbiota, but the relationship between body weight and oral microbiota is less clear especially in young children. We aimed to evaluate if there is an association between child growth and the saliva microbiome. We hypothesized that associations between growth and the saliva microbiome would be moderate, similarly to the association between growth and the gut microbiome. For 236 toddlers participating in the New Hampshire Birth Cohort Study, we characterized the association between multiple longitudinal anthropometric measures of body height, body weight and body mass. Body Mass Index (BMI) z-scores were calculated, and dual-energy x-ray absorptiometry (DXA) was used to estimate body composition. Shotgun metagenomic sequencing of saliva samples was performed to taxonomically and functionally profile the oral microbiome. We found that within-sample diversity was inversely related to body mass measurements while community composition was not associated. Although the magnitude of associations were small, some taxa were consistently associated with growth and modified by sex. Certain taxa were associated with decreased weight or growth (including Actinomyces odontolyticus and Prevotella melaninogenica) or increased growth (such as Streptococcus mitis and Corynebacterium matruchotii) across anthropometric measures. Further exploration of the functional significance of this relationship will enhance our understanding of the intersection between weight gain, microbiota, and energy metabolism and the potential role of these relationships on the onset of obesity-associated diseases in later life.

Anthropometry-based prediction of body composition in early infancy compared to air-displacement plethysmography

BACKGROUND

Anthropometry-based equations are commonly used to estimate infant body composition. However, existing equations were designed for newborns or adolescents. We aimed to (a) derive new prediction equations in infancy against air-displacement plethysmography (ADP-PEA Pod) as the criterion, (b) validate the newly developed equations in an independent infant cohort and (c) compare them with published equations (Slaughter-1988, Aris-2013, Catalano-1995).

METHODS

Cambridge Baby Growth Study (CBGS), UK, had anthropometry data at 6 weeks (N = 55) and 3 months (N = 64), including skinfold thicknesses (SFT) at four sites (triceps, subscapular, quadriceps and flank) and ADP-derived total body fat mass (FM) and fat-free mass (FFM). Prediction equations for FM and FFM were developed in CBGS using linear regression models and were validated in Sophia Pluto cohort, the Netherlands, (N = 571 and N = 447 aged 3 and 6 months, respectively) using Bland-Altman analyses to assess bias and 95% limits of agreement (LOA).

RESULTS

CBGS equations consisted of sex, age, weight, length and SFT from three sites and explained 65% of the variance in FM and 79% in FFM. In Sophia Pluto, these equations showed smaller mean bias than the three published equations in estimating FM: mean bias (LOA) 0.008 (-0.489, 0.505) kg at 3 months and 0.084 (-0.545, 0.713) kg at 6 months. Mean bias in estimating FFM was 0.099 (-0.394, 0.592) kg at 3 months and -0.021 (-0.663, 0.621) kg at 6 months.

CONCLUSIONS

CBGS prediction equations for infant FM and FFM showed better validity in an independent cohort at ages 3 and 6 months than existing equations.

Examination of the '5-2-1-0' Recommendations in Racially Diverse Young Children Exposed to Tobacco Smoke

PURPOSE

The '5-2-1-0' guidelines recommend that children: eat ≥5 servings of fruits/vegetables ('5'), have ≤2 hours of screen-time ('2'), have ≥1 hour of activity ('1'), and drink 0 sugar-sweetened beverages ('0') daily. The pediatric emergency department (PED) treats children at risk for obesity and tobacco smoke exposure (TSE). We examined body mass index (BMI), overweight, obesity, TSE, and '5-2-1-0' rates in children with TSE in the PED.

DESIGN

Cross-sectional study of PED children.

SETTING

The PED of a children's hospital.

SAMPLE

Children with TSE >6 months-5 years old (N = 401).

MEASURES

Sociodemographics, '5-2-1-0' behaviors, BMI, and cotinine-confirmed TSE.

ANALYSIS

Associations between '5-2-1-0' and sociodemographics were examined with logistic regression.

RESULTS

Mean (SD) age = 2.4 (1.6) years; 53.1% were Black; 65.8% had low-income; and 93.4% had TSE. Of 2-5-year-olds, mean (SD) BMI percentile was 66.2 (30.1), 16.1% were overweight and 20.6% were obese. In total, 10.5% attained '5', 72.6% attained '2', 57.8% of 2-5-year-olds attained '1', and 9.8% attained '0'. Compared to White children, "other" race children were more likely to meet '5' (aOR(95% CI):4.67(1.41, 5.45)); 2-5-years-olds (aOR(95%CI):0.60(0.38, 0.95)) and Black children (aOR(95%CI):0.36(0.21, 0.60)) were at decreased odds to meet '2' compared to younger or White children, respectively. Compared to younger children, 2-5-year-olds were at decreased odds to meet '0' (aOR(95%CI):0.08(0.02, 0.26)).

CONCLUSION

Racially diverse, low-income children with TSE had low '5-2-1-0' attainment. Interventions are needed to improve lifestyle habits in this population.

Impact of a targeted volume-increase nutrition guideline on growth and body mass index in premature infants: A retrospective review

BACKGROUND

The negative impact of disproportionate growth in premature infants is well documented, but optimal nutrition practices needed to prevent an unhealthy body mass index (BMI) remain unclear.

METHODS

An evidence-based, volume-increase guideline that advanced feeding volumes from 150-160 to 170-180 ml/kg/day between the postmenstrual age (PMA) of 31 0/7 and 34 0/7 weeks was implemented in October 2017 for infants born at ≤32 0/7 weeks' gestational age. Data were collected on 262 infants' weight and length at birth and at discharge for 20 months before and 21 months after guideline implementation, and retrospective analysis was conducted to determine disproportionate growth by comparing BMIs (in g/cm² ) at birth and at discharge. Changes in infants' body habitus were determined through bivariate analysis of weight and length z-scores from the Fenton growth curve.

RESULTS

Implementation of a targeted volume nutrition guideline resulted in fewer infants with growth failure, defined as weight <10th percentile (19.5% vs 11.2%; P = .06) at discharge. Infants who received treatment according to the targeted nutrition guideline had a statistically significant reduction in disproportionately low BMI (8.6% vs 2.5%; P = .0380) and an increase in disproportionately high BMIs (4.3% vs 12.3%; P = .025). There was minor change in the percentage of disproportionately large infants who received the guidelines from birth to discharge (11.5% vs 12.3%).

CONCLUSIONS

A targeted volume-increase nutrition guideline may prevent growth failure, with some effects on disproportionate growth in preterm infants born at ≤32 0/7 weeks' gestational age.

Integrating anthropometric and cardiometabolic health methods in stress, early experiences, and development (SEED) science

Within Stress, Early Experiences, and Development (SEED) science, there is a growing body of research demonstrating complex associations not only between stress, development, and psychopathology, but also with chronic disease risk factors. We argue that it is important for SEED researchers to consider including child anthropometric and physical health measures to more comprehensively capture processes of risk and resilience. Broader adoption of harmonized anthropometry and health measures in SEED research will facilitate collaborations, yielding larger datasets for research in high-risk populations, and greater opportunity to replicate existing findings. In this review, we identify optimal anthropometric and cardiometabolic health measurement methods used from infancy through adolescence, including those that are low-burden and inexpensive. Methods covered include: waist, hip, and head circumference, height, length, weight, pubertal development, body composition, blood pressure, arterial stiffness, carotid intima media thickness, and serum measures of cardiometabolic risk and inflammation. We provide resources for SEED researchers to integrate these methods into projects or to better understand these methods when reading the literature as well as where to find collaborators for more in-depth studies incorporating these measures. With broader integration of psychological and physical health measures in SEED research, we can better inform theory and interventions to promote health and resilience in individuals who have experienced early stress.

Vitamin D supplementation for term breastfed infants to prevent vitamin D deficiency and improve bone health

BACKGROUND

Vitamin D deficiency is common worldwide, contributing to nutritional rickets and osteomalacia which have a major impact on health, growth, and development of infants, children and adolescents. Vitamin D levels are low in breast milk and exclusively breastfed infants are at risk of vitamin D insufficiency or deficiency.

OBJECTIVES

To determine the effect of vitamin D supplementation given to infants, or lactating mothers, on vitamin D deficiency, bone density and growth in healthy term breastfed infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to 29 May 2020 supplemented by searches of clinical trials databases, conference proceedings, and citations.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs in breastfeeding mother-infant pairs comparing vitamin D supplementation given to infants or lactating mothers compared to placebo or no intervention, or sunlight, or that compare vitamin D supplementation of infants to supplementation of mothers.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias and independently extracted data. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included 19 studies with 2837 mother-infant pairs assessing vitamin D given to infants (nine studies), to lactating mothers (eight studies), and to infants versus lactating mothers (six studies). No studies compared vitamin D given to infants versus periods of infant sun exposure. Vitamin D supplementation given to infants: vitamin D at 400 IU/day may increase 25-OH vitamin D levels (MD 22.63 nmol/L, 95% CI 17.05 to 28.21; participants = 334; studies = 6; low-certainty) and may reduce the incidence of vitamin D insufficiency (25-OH vitamin D < 50 nmol/L) (RR 0.57, 95% CI 0.41 to 0.80; participants = 274; studies = 4; low-certainty). However, there was insufficient evidence to determine if vitamin D given to the infant reduces the risk of vitamin D deficiency (25-OH vitamin D < 30 nmol/L) up till six months of age (RR 0.41, 95% CI 0.16 to 1.05; participants = 122; studies = 2), affects bone mineral content (BMC), or the incidence of biochemical or radiological rickets (all very-low certainty). We are uncertain about adverse effects including hypercalcaemia. There were no studies of higher doses of infant vitamin D (> 400 IU/day) compared to placebo. Vitamin D supplementation given to lactating mothers: vitamin D supplementation given to lactating mothers may increase infant 25-OH vitamin D levels (MD 24.60 nmol/L, 95% CI 21.59 to 27.60; participants = 597; studies = 7; low-certainty), may reduce the incidences of vitamin D insufficiency (RR 0.47, 95% CI 0.39 to 0.57; participants = 512; studies = 5; low-certainty), vitamin D deficiency (RR 0.15, 95% CI 0.09 to 0.24; participants = 512; studies = 5; low-certainty) and biochemical rickets (RR 0.06, 95% CI 0.01 to 0.44; participants = 229; studies = 2; low-certainty). The two studies that reported biochemical rickets used maternal dosages of oral D3 60,000 IU/day for 10 days and oral D3 60,000 IU postpartum and at 6, 10, and 14 weeks. However, infant BMC was not reported and there was insufficient evidence to determine if maternal supplementation has an effect on radiological rickets (RR 0.76, 95% CI 0.18 to 3.31; participants = 536; studies = 3; very low-certainty). All studies of maternal supplementation enrolled populations at high risk of vitamin D deficiency. We are uncertain of the effects of maternal supplementation on infant growth and adverse effects including hypercalcaemia. Vitamin D supplementation given to infants compared with supplementation given to lactating mothers: infant vitamin D supplementation compared to lactating mother supplementation may increase infant 25-OH vitamin D levels (MD 14.35 nmol/L, 95% CI 9.64 to 19.06; participants = 269; studies = 4; low-certainty). Infant vitamin D supplementation may reduce the incidence of vitamin D insufficiency (RR 0.61, 95% CI 0.40 to 0.94; participants = 334; studies = 4) and may reduce vitamin D deficiency (RR 0.35, 95% CI 0.17 to 0.72; participants = 334; studies = 4) but the evidence is very uncertain. Infant BMC and radiological rickets were not reported and there was insufficient evidence to determine if maternal supplementation has an effect on infant biochemical rickets. All studies enrolled patient populations at high risk of vitamin D deficiency. Studies compared an infant dose of vitamin D 400 IU/day with varying maternal vitamin D doses from 400 IU/day to > 4000 IU/day. We are uncertain about adverse effects including hypercalcaemia.

AUTHORS' CONCLUSIONS

For breastfed infants, vitamin D supplementation 400 IU/day for up to six months increases 25-OH vitamin D levels and reduces vitamin D insufficiency, but there was insufficient evidence to assess its effect on vitamin D deficiency and bone health. For higher-risk infants who are breastfeeding, maternal vitamin D supplementation reduces vitamin D insufficiency and vitamin D deficiency, but there was insufficient evidence to determine an effect on bone health. In populations at higher risk of vitamin D deficiency, vitamin D supplementation of infants led to greater increases in infant 25-OH vitamin D levels, reductions in vitamin D insufficiency and vitamin D deficiency compared to supplementation of lactating mothers. However, the evidence is very uncertain for markers of bone health. Maternal higher dose supplementation (≥ 4000 IU/day) produced similar infant 25-OH vitamin D levels as infant supplementation of 400 IU/day. The certainty of evidence was graded as low to very low for all outcomes.

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.

Complementary feeding practices and their association with adiposity indicators at 12 months of age

Nutrition during the first 1000 days of life represents a window of opportunity to reduce the risk of metabolic dysfunctions later in life. Exclusive breastfeeding (EBF) and adequate introduction of solid foods are essential to promote metabolic and nutritional benefits. We evaluated the association of infant feeding practices from birth to 6 months (M) with adiposity indicators at 12 M. We performed a secondary analysis of 106 healthy term infants born from a cohort of healthy pregnant women. Type of breastfeeding (exclusive or nonexclusive), the start of complementary feeding (CF) (before (<4 M) or after (≥4 M)), and adiposity (body mass index - BMI, body mass index-for-age - BMI/A, waist circumference - WC, and waist circumference-length ratio - WLR) were evaluated at 12 M using descriptive statistics, mean differences, X2, and linear regression models. During the first 6 M, 28.3% (n = 30) of the infants received EBF. Early CF (<4 M) was present in 26.4% (n = 28) of the infants. Children who started CF < 4 M were less breastfed, received added sugars as the most frequently introduced food category, and showed higher BMI, BMI/A, WC, and WLR; those who consumed added sugars early (<4 M) had a higher WC. Starting CF < 4 M was the main factor associated with a higher WC at 12 M. Unhealthy infant feeding practices, such as lack of EBF, early CF, and early introduction of sugars, may be associated with higher adiposity at 12 M.

Increased Adiposity Associated With Increased Length of Stay for Infants With Bronchiolitis

OBJECTIVES

Excess adiposity upregulates proinflammatory adipokines in infancy that have also been implicated in the pathogenesis of bronchiolitis. The association between excess adiposity and severity of disease in bronchiolitis is unclear. We sought to examine the association between adiposity and length of hospitalization and risk of PICU transfer in children with bronchiolitis.

METHODS

We conducted a retrospective cohort study examining infants 24 months and younger hospitalized at an academic children's hospital with bronchiolitis, grouped by weight status (BMI z score and ponderal index). Data were extracted from the medical record, including the following relevant covariates: age, sex, race and/or ethnicity, and International Classification of Diseases, 10th Revision codes. Outcomes included length of stay (LOS) and PICU transfer. We used multiple regression to examine the association between each anthropometric measure and LOS and likelihood of PICU transfer.

RESULTS

There were 765 children in the final sample, 599 without a significant comorbidity (eg, prematurity, congenital heart disease). The median LOS was 2.8 days (interquartile range 1.7-4.9 days). LOS increased with increasing ponderal index quartile (P = .001). After accounting for age and significant comorbidities, we used multivariable regression to identify a significant association between increasing ponderal index and LOS (P = .04) and no association between BMI and LOS. Logistic regression did not reveal an association between either anthropometric measure and PICU transfer.

CONCLUSIONS

In this study, we identified an association between a measure of excess adiposity in infants and length of hospitalization for bronchiolitis. Further work is needed to confirm this association, examine potential mechanisms, and account for other potential confounders.

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

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

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

GWAS on longitudinal growth traits reveals different genetic factors influencing infant, child, and adult BMI

Early childhood growth patterns are associated with adult health, yet the genetic factors and the developmental stages involved are not fully understood. Here, we combine genome-wide association studies with modeling of longitudinal growth traits to study the genetics of infant and child growth, followed by functional, pathway, genetic correlation, risk score, and colocalization analyses to determine how developmental timings, molecular pathways, and genetic determinants of these traits overlap with those of adult health. We found a robust overlap between the genetics of child and adult body mass index (BMI), with variants associated with adult BMI acting as early as 4 to 6 years old. However, we demonstrated a completely distinct genetic makeup for peak BMI during infancy, influenced by variation at the LEPR/LEPROT locus. These findings suggest that different genetic factors control infant and child BMI. In light of the obesity epidemic, these findings are important to inform the timing and targets of prevention strategies.

Associations of Pre-Pregnancy BMI, Gestational Weight Gain and Maternal Parity with the Trajectory of Weight in Early Childhood: A Prospective Cohort Study

Background: The association of maternal parity, pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) with childhood weight status has been well studied; however, little is known about these factors with respect to the rate of weight changes in early childhood. Methods: This study was based on a prospective longitudinal study. The follow-up surveys were conducted at the ages of 1, 3, 6, 8, 12, and 18 months. Child weight was investigated twice at each wave. Data on maternal parity, pre-pregnancy weight and height were collected at baseline. The latent growth curve model was used to examine the effects of interested predictors on the trajectory of weight in early childhood. Results: Finally, 893 eligible mother-child pairs were drawn from the cohort. In adjusted models, multiparas were associated with higher birth weight (β = 0.103) and slower weight change rate of children (β = −0.028). Pre-conception BMI (β = 0.034) and GWG (β = 0.014) played important roles in the initial status of child weight but did not have effects on the rate of weight changes of the child. Conclusions: Multiparous pregnancy is associated with both higher mean birth weight and slower weight-growth velocity in early childhood, while pregravid maternal BMI and GWG are only related to the birth weight.

Anthropometric and clinical correlates of fat mass in healthy term infants at 6 months of age

BACKGROUND

Body composition in infancy plays a central role in the programming of metabolic diseases. Fat mass (FM) is determined by personal and environmental factors. Anthropometric measurements allow for estimations of FM in many age groups; however, correlations of these measurements with FM in early stages of life are scarcely reported. The aim of this study was to evaluate anthropometric and clinical correlates of FM in healthy term infants at 6 months of age.

METHODS

Healthy term newborns (n = 102) from a prospective cohort. Weight, length, skinfolds (biceps, triceps, subscapular and the sum -SFS-) and waist circumference (WC) were measured at 6 months. Body mass index (BMI) and WC/length ratio were computed. Type of feeding during the first 6 months of age was recorded. Air displacement plethysmography was used to asses FM (percentage -%-) and FM index (FMI) was calculated. Correlations and general linear models were performed to evaluate associations.

RESULTS

Significant correlations were observed between all anthropometric measurements and FM (% and index)(p < 0.001). Exclusive/predominant breastfed infants had higher FM and anthropometric measurements at 6 months. Models that showed the strongest associations with FM (% and index) were SFS + WC + sex + type of feeding.

CONCLUSIONS

Anthropometry showed good correlations with FM at 6 months of age. Skinfolds sum and waist circumference were the strongest anthropometric variables associated to FM. Exclusive/predominant breastfeeding was strongly associated with FM.

Association of Weight for Length vs Body Mass Index During the First 2 Years of Life With Cardiometabolic Risk in Early Adolescence

Importance

The American Academy of Pediatrics currently recommends weight for length (WFL) for assessment of weight status in children younger than 2 years but body mass index (BMI) for children older than 2 years. However, the clinical implications of using WFL vs BMI in children younger than 2 years as an indicator of future health outcomes remains understudied.

Objective

To compare associations of overweight based on WFL vs BMI in children younger than 2 years with cardiometabolic outcomes during early adolescence.

Design, Setting, and Participants

This prospective study of birth cohorts in the United States (Project Viva) and Belarus (Promotion of Breastfeeding Intervention Trial [PROBIT]) performed from June 1, 1996, to November 31, 2002, included 13 666 children younger than 2 years.

Main Exposures

Overweight defined as Centers for Disease Control and Prevention (CDC) WFL in the 95th percentile or greater, World Health Organization (WHO) WFL in the 97.7th percentile or greater, or WHO BMI in the 97.7th percentile or greater at 6, 12, 18, or 24 months of age.

Main Outcomes and Measures

Primary outcomes were fat mass index, insulin resistance, metabolic risk score, and obesity during early adolescence. Secondary outcomes were height and BMI z scores, sum of skinfolds, waist circumference, and systolic blood pressure during early adolescence.

Results

The study included 919 children (mean [SD] age, 12.9 [0.9] years; 460 [50.1%] male; and 598 [65.1%] white) from Project Viva and 12 747 children (mean [SD] age, 11.5 [0.5] years; 6204 [48.7%] male; and 12 747 [100%] white) from PROBIT. During 6 to 24 months of age, in Project Viva, 206 children (22.4%) were overweight at any of the 4 times points according to the CDC WFL, 160 (17.4%) according to WHO WFL, and 161 (17.5%) according to WHO BMI cut points. In PROBIT, 3715 children (29.1%) were overweight at any of the 4 time points according to the CDC WFL, 3069 (24.1%) according to WHO WFL, and 3125 (24.5%) according to WHO BMI cut points. After maternal and child characteristics were adjusted for, being ever overweight (vs never overweight) during 6 to 24 months of age was associated with higher likelihood of adverse cardiometabolic risk markers during early adolescence, but associations did not differ substantially across WFL and BMI cut points in either cohort. For example, for fat mass index in Project Viva, β = 0.9 (95% CI, 0.5-1.4) for the CDC WFL, β = 1.1 (95% CI, 0.6-1.6) for WHO WFL, and β = 1.4 (95% CI, 0.9-1.9) for WHO BMI. For PROBIT, β = 0.5 (95% CI, 0.4-0.6) for the CDC WFL, β = 0.6 (95% CI, 0.5-0.7) for WHO WFL, and β = 0.6 (95% CI, 0.5-0.6) for WHO BMI. Neither growth metric in infancy was superior over the others based on F statistics (Project Viva: 17.1-17.8; PROBIT: 87.1-88.7). Findings were similar for insulin resistance, metabolic risk score, obesity, and secondary outcomes.

Conclusions and Relevance

Choice of WFL vs BMI to define overweight during the first 2 years of life may not greatly affect the association with cardiometabolic outcomes during early adolescence. The findings appear to have important implications for investigators seeking to use BMI as a growth metric for epidemiologic research and for practitioners monitoring the weight status of children younger than 2 years.