Infant Growth Trajectories Research Articles

Prenatal exposure to persistent organic pollutants and changes in infant growth and childhood growth trajectories

BackgroundChildren are born with a burden of persistent organic pollutants (POPs) which may have endocrine disrupting properties and have been postulated to contribute to the rise in childhood obesity. The current evidence is equivocal, which may partly because many studies investigate the effects at one time point during childhood. We assessed associations between prenatal exposure to POPs and growth during infancy and childhood. MethodsWe used data from two Belgian cohorts with cord blood measurements of five organochlorines [(dichlorodiphenyldichloroethylene (p,p’-DDE), hexachlorobenzene (HCB), polychlorinated biphenyls (PCB-138, -150, −180)] (N = 1418) and two perfluoroalkyl substances [perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)] (N = 346). We assessed infant growth, defined as body mass index (BMI) z-score change between birth and 2 years, and childhood growth, characterized as BMI trajectory from birth to 8 years. To evaluate associations between POP exposures and infant growth, we applied a multi-pollutant approach, using penalized elastic net regression with stability selection, controlling for covariates. To evaluate associations with childhood growth, we used single-pollutant linear mixed models with random effects for child individual, parametrized using a natural cubic spline formulation. ResultsPCB-153 was associated with increased and p,p’-DDE with decreased infant growth, although these results were imprecise. No clear association between any of the exposures and longer-term childhood growth trajectories was observed. We did not find evidence of effect modification by child sex. ConclusionOur results suggest that prenatal exposure to PCB-153 and p,p’-DDE may affect infant growth in the first two years, with no evidence of more persistent effects.

Body Composition Trajectories During the First 23 Months of Life Differ by HIV Exposure Among Infants in Western Kenya: A Prospective Study

BackgroundInfants who are HIV-exposed and uninfected have suboptimal growth patterns compared to those who are HIV-unexposed and uninfected. However, little is known about how these patterns persist beyond 1 year of life. ObjectivesThis study aimed to examine whether infant body composition and growth trajectories differed by HIV exposure during the first 2 years of life among Kenyan infants using advanced growth modeling. MethodsRepeated infant body composition and growth measurements (mean: 6; range: 2–7) were obtained from 6 weeks to 23 months in the Pith Moromo cohort in Western Kenya (n = 295, 50% HIV-exposed and uninfected, 50% male). Body composition trajectory groups were fitted using latent class mixed modeling (LCMM) and associations between HIV exposure and growth trajectories were examined using logistic regression analysis. ResultsAll infants exhibited poor growth. However, HIV-exposed infants generally grew suboptimally than unexposed infants. Across all body composition models except for the sum of skinfolds, HIV-exposed infants had a higher likelihood of belonging to the suboptimal growth groups identified by LCMM than the HIV-unexposed infants. Notably, HIV-exposed infants were 3.3 times more likely (95% CI: 1.5–7.4) to belong to the length-for-age z-score growth class that remained at a z-score of < −2, indicating stunted growth. HIV-exposed infants were also 2.6 times more likely (95% CI: 1.2–5.4) to belong to the weight-for-length-for-age z-score growth class that remained between 0 and −1, and were 4.2 times more likely (95% CI: 1.9–9.3) to belong to the weight-for-age z-score growth class that indicated poor weight gain besides stunted linear growth. ConclusionsIn a cohort of Kenyan infants, HIV-exposed infants grew suboptimally compared to HIV-unexposed infants beyond 1 year of age. These growth patterns and longer-term effects should be further investigated to support the ongoing efforts to reduce early-life HIV exposure-related health disparities.

Human Milk Microbiome and Microbiome-Related Products: Potential Modulators of Infant Growth

Infant growth trajectory may influence later-life obesity. Human milk provides a wide range of nutritional and bioactive components that are vital for infant growth. Compared to formula-fed infants, breastfed infants are less likely to develop later-onset obesity, highlighting the potential role of bioactive components present in human milk. Components of particular interest are the human milk microbiota, human milk oligosaccharides (HMOs), short-chain fatty acids (SCFAs), and antimicrobial proteins, each of which influence the infant gut microbiome, which in turn has been associated with infant body composition. SCFAs and antimicrobial proteins from human milk may also systemically influence infant metabolism. Although inconsistent, multiple studies have reported associations between HMOs and infant growth, while studies on other bioactive components in relation to infant growth are sparse. Moreover, these microbiome-related components may interact with each other within the mammary gland. Here, we review the evidence around the impact of human milk microbes, HMOs, SCFAs, and antimicrobial proteins on infant growth. Breastfeeding is a unique window of opportunity to promote optimal infant growth, with aberrant growth trajectories potentially creating short- and long-term public health burdens. Therefore, it is important to understand how bioactive components of human milk influence infant growth.

Maternal Metals Exposure and Infant Weight Trajectory: The Japan Environment and Children's Study (JECS).

To our knowledge, the association of maternal exposure to metallic elements with weight trajectory pattern from the neonatal period has not been investigated. The goals of this study were to identify infant growth trajectories in weight in the first 3 y of life and to determine the associations of maternal blood levels of lead, cadmium, mercury, selenium, and manganese with growth trajectory. This longitudinal study, part of the Japan Environment and Children Study, enrolled 103,099 pregnant women at 15 Regional Centres across Japan between 2011 and 2014. Lead, cadmium, mercury, selenium, and manganese levels were measured in blood samples collected in the second (14-27 wk gestational age) or third trimester (). Growth trajectory of 99,014 children was followed until age 3 y. Raw weight values were transformed to age- and sex-specific weight standard deviation (SD) scores, and latent-class group-based trajectory models were estimated to determine weight trajectories. Associations between maternal metallic element levels and weight trajectory were examined using multinomial logistic regression models after confounder adjustment. We identified 5 trajectory patterns based on weight SD score: 4.74% of infants were classified in Group I, very small to small; 31.26% in Group II, moderately small; 21.91% in Group III, moderately small to moderately large; 28.06% in Group IV, moderately large to normal; and 14.03% in Group V, moderately large to large. On multinomial logistic regression, higher maternal lead and selenium levels tended to be associated with increased odds ratios (ORs) of poor weight SD score trajectories (Groups I and II), in comparison with Group III. Higher levels of mercury were associated with decreased ORs, whereas higher levels of manganese were associated with increased ORs of "moderately large" trajectories (Groups IV and V). Maternal lead, mercury, selenium, and manganese blood levels affect infant growth trajectory pattern in the first 3 y of life. https://doi.org/10.1289/EHP10321.

The Longitudinal Relation between Infant Feeding Styles and Growth Trajectories among Families from Low-Income Households

BackgroundParental feeding styles, including the emotional environment parents create to modify a child’s eating behaviors, have been associated with measures of adiposity in cross-sectional studies. The longitudinal relation between parental feeding styles in early infancy and adiposity in later infancy/toddlerhood are scant and have shown mixed results, particularly in families from low-income households. ObjectivesThis study examined the relation between parental feeding styles and infant BMI z-score trajectories between 6 and 18 mo in families from low-income households. MethodsParent–infant dyads were recruited during the infant’s 6-, 9-, or 12-mo well-child visit. Feeding styles were assessed using the Infant Feeding Style Questionnaire (IFSQ). Infant anthropometrics from birth through 18 mo were extracted from the electronic medical record. BMI z-score slopes were estimated for each infant between 0-6 mo and 6–18 mo. Associations between feeding styles and BMI z-score slopes were examined using mixed models controlling for demographic, clinical, and feeding covariates. ResultsThe final analytic sample included 198 dyads (69% Black; median infant age: 9.0 mo; IQR: 6.8–10.3 mo). The predominant parent feeding styles included the following: laissez-faire (30%), restrictive (28%), responsive (23%), and pressuring (19%). In adjusted models, the predominant feeding style at enrollment was associated with the BMI z-score slope between 6 and 18 mo, with the responsive feeding style exhibiting a steeper increase in BMI z-score than other feeding styles. Infant feeding style was not associated with BMI z-score slope between birth and 6 mo of age. Infants of parents who exhibited restrictive feeding styles were more likely to have a BMI ≥85th percentile at their last measurement. ConclusionsThe predominant parent feeding style during infancy in a low-income population was associated with infant BMI z-score between 6 and 18 mo of age, but not earlier. Further studies are needed to better understand how predictive factors collectively contribute to BMI increase in the first 2 y.

Early predictors of short duration of exclusive breastfeeding among Havana women

ProblemIn Cuba, only 40.9% of infants under the age of six months are exclusively breastfed with the average duration of exclusivity being only 2.4 months. Evidence to guide the development of breastfeeding interventions among Cuban women to achieve exclusive breastfeeding to six months is limited. The objective was to identify early predictors for discontinuation of exclusive breastfeeding before six months among Cuban women. MethodsIn a cohort study, 273 maternal-infant pairs were recruited immediately following childbirth at a public hospital in Havana, Cuba and followed up to six months postpartum. A univariate and multivariate strategy was used to identify early predictors of the discontinuation of exclusive breastfeeding before six months. ResultsWhile all women were exclusively breastfeeding at hospital discharge, only 20.5% continued to six months postpartum. The average duration of exclusive breastfeeding was 3.13 months (SD ± 2.14 months). Factors associated with the early discontinuation of exclusive breastfeeding were: (1) breastfeeding not initiated within the first hour of birth, (2) infant birthweight <3.3 kgs, (3) pacifier use, (4) maternal dissatisfaction with infant growth, (5) maternal mental health problems at one month and (6) low breastfeeding self-efficacy at birth and one month. In the multivariate analysis, only maternal dissatisfaction with infant growth progress at one month and birth weight <3.3 kg predicted the early discontinuation of exclusive breastfeeding. ConclusionWomen who gave birth to an infant with a lower birth weight and were dissatisfied with their infant's growth trajectory were high risk to prematurely discontinue exclusive breastfeeding before six months.

Racial and Ethnic Differences in Infant Feeding Practices and Growth Trajectories Among Low-Income Households

Objectives(1) To examine duration and intensity of breastfeeding, age of introduction to solids/other liquids, and complementary feeding choices among racial/ethnic minority infants living in low-income households. (2) To determine the association between feeding choices and model growth trajectory from early to late infancy in the study population.MethodsMother-infant dyads were recruited from a pediatric clinic mainly serving low-income and/or Medicaid-recipient families. Mothers were interviewed in English or Spanish to collect sociodemographic, food security status, and feeding practices when the infant was 2, 4, 6, 9, and 12 months of age (n = 249). From 6-months onwards, 24-hour feeding recalls were conducted to estimate daily nutrient intake. Infant height and weight were retrieved from the electronic medical record to estimate growth trajectories from early to late infancy.ResultsBy race/ethnicity, the majority of the participants were African American (46%) or Hispanic (35%). The prevalence of low to very low food insecurity was 10%. Exclusive breastfeeding was not common among dyads at 2 (26%), 4 (17%), and 6 months (4%). Partial breastfeeding was significantly higher among Hispanic mothers (P < .05). For instance, at 4 months 72% of Hispanic mothers partially breastfed compared to 34% African American and 31% of non-Hispanic White mothers (p < .001). Early introduction to solids/other liquids was more common within African American dyads (p < .05). Preliminary growth trajectory modeling indicated some racial/ethnic differences, especially the weight of Hispanic infants was marginally higher compared to non-Hispanic white infants (p = .072) in late infancy.ConclusionsSignificant differences in infant feeding practices, including breastfeeding and introduction to solids/liquids, exist by race/ethnicity. Examination of these differences in feeding practices will be critical to understanding how they affect growth trajectory from early to late infancy.Funding SourcesNational Institute of Health NICHD.

New insights on growth trajectory in infants with complex congenital heart disease

PurposeWe aimed to describe the weight-for-age Z-score growth trajectory (WAZ-GT) of infants with complex congenital heart disease (cCHD) after neonatal cardiac surgery in the first 4 months of life and assess potential risk factors. MethodsWe utilized data from a previously reported trial of the REACH telehealth home monitoring (NCT01941667) program which evaluated 178 infants with cCHD from 2012 to 2017. Over the first 4 months of life, weekly infant weights were converted to WAZ. WAZ-GT classes were identified using latent class growth modeling. Multinomial logistic regression models were used to examine the associations between potential risk factors and WAZ-GT classes. ResultsFour distinct classes of WAZ-GT were identified: maintaining WAZ > 0, 14%; stable around WAZ = 0, 35%; partially recovered, 28%; never recovered, 23%. Compared with reference group “stable around WAZ=0,” we identified clinical and sociodemographic determinants of class membership for the three remaining groups. “Maintaining WAZ > 0” had greater odds of having biventricular physiology, borderline appetite, and a parent with at least a college education. “Partially recovered” had greater odds of hospital length of stay>14 days and being a single child in the household. “Never recovered” had greater odds hospital length of stay >14 and > 30 days, tube feeding at discharge, and low appetite. ConclusionsThis study described distinct classes of WAZ-GT for infants with cCHD early in infancy and identified associated determinants. Practice implicationsFindings from this study can be used in the identification of infants at risk of poor WAZ-GT and in the design of interventions to target growth in this vulnerable patient population.

Association Between Trajectory Patterns of Body Mass Index Change Up to 10 Months and Early Gut Microbiota in Preterm Infants.

Recent research suggests that gut microbiota plays an important role in the occurrence and development of excessive weight and obesity, and the early-life gut microbiota may be correlated with weight gain and later growth. However, the association between neonatal gut microbiota, particularly in preterm infants, and excessive weight and obesity remains unclear. To evaluate the relationship between gut microbiota and body mass index (BMI) growth trajectories in preterm infants, we examined microbial composition by performing 16S rDNA gene sequencing on the fecal samples from 75 preterm infants within 3 months after birth who were hospitalized in the neonatal intensive care unit of Hunan Children’s Hospital from August 1, 2018 to October 31, 2019. Then, we collected their physical growth information during 0–10 months. Latent growth mixture models were used to estimate growth trajectories of infantile BMI, and the relationship between the gut microbiota and the BMI growth trajectories was analyzed. The results demonstrated that there were 63,305 and 61 operational taxonomic units in the higher BMI group (n = 18), the lower BMI group (n = 51), and the BMI catch-up group (n = 6), respectively. There were significant differences in the abundance of the gut microbiota, but no significant differences in the diversity of it between the lower and the higher BMI group. The BMI growth trajectories could not be clearly distinguished because principal component analysis showed that gut microbiota composition among these three groups was similar. The three groups were dominated by Firmicutes and Proteobacteria in gut microbiota composition, and the abundance of Lactobacillus in the higher BMI group was significantly different from the lower BMI group. Further intervention experiments and dynamic monitoring are needed to determine the causal relationship between gut microbiota differences and the BMI change.

Infant Growth Trajectories and Lipid Levels in Adolescence: Evidence From a Chilean Infancy Cohort.

Growth in early infancy is hypothesized to affect chronic disease risk factors later in life. To date, most reports draw on European-ancestry cohorts with few repeated observations in early infancy. We investigated the association between infant growth before 6 months and lipid levels in adolescents in a Hispanic/Latino cohort. We characterized infant growth from birth to 5 months in male (n= 311) and female (n= 285) infants from the Santiago Longitudinal Study (1991-1996) using 3 metrics: weight (kg), length (cm), and weight-for-length (g/cm). Superimposition by translation and rotation (SITAR) and latent growth mixture models (LGMMs) were used to estimate the association between infant growth characteristics and lipid levels at age 17 years. We found a positive relationship between the SITAR length velocity parameter before 6 months of age and high-density lipoprotein cholesterol levels in adolescence (11.5, 95% confidence interval; 3.4, 19.5), indicating higher high-density lipoprotein cholesterol levels occurring with faster length growth. The strongest associations from the LGMMs were between higher low-density lipoprotein cholesterol and slower weight-for-length growth, following a pattern of associations between slower growth and adverse lipid profiles. Further research in this window of time can confirm the association between early infant growth as an exposure and adolescent cardiovascular disease risk factors.

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

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. 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. 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. 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. 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.

Effects of Complementary Feeding With Different Protein-Rich Foods on Infant Growth and Gut Health: Study Protocol.

Background: An urgent need exists for evidence-based dietary guidance early in life, particularly regarding protein intake. However, a significant knowledge gap exists in the effects of protein-rich foods on growth and development during early complementary feeding.Methods: This is a randomized controlled trial of infant growth and gut health (primary outcomes). We directly compare the effects of dietary patterns with common protein-rich foods (meat, dairy, plant) on infant growth trajectories and gut microbiota development (monthly assessments) during early complementary feeding in both breast- and formula-fed infants. Five-month-old infants (up to n = 300) are randomized to a meat-, dairy-, plant-based complementary diet or a reference group (standard of care) from 5 to 12 months of age, with a 24-month follow-up assessment. Infants are matched for sex, mode of delivery and mode of feeding using stratified randomization. Growth assessments include length, weight, head circumference and body composition. Gut microbiota assessments include both 16S rRNA profiling and metagenomics sequencing. The primary analyses will evaluate the longitudinal effects of the different diets on both anthropometric measures and gut microbiota. The secondary analysis will evaluate the potential associations between gut microbiota and infant growth.Discussion: Findings are expected to have significant scientific and health implications for identifying beneficial gut microbial changes and dietary patterns and for informing dietary interventions to prevent the risk of overweight and later obesity, and promote optimal health.Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT05012930.

Maternal BMI, breastfeeding and perinatal factors that influence early childhood growth trajectories: a scoping review

Obesity rates among children are rapidly rising internationally and have been linked to noncommunicable diseases in adulthood. Individual preventive strategies have not effectively reduced global obesity rates, leading to a gap in clinical services regarding the development of early perinatal interventions. The objective of this scoping review is to explore the relationship between maternal BMI and breastfeeding behaviors on child growth trajectories to determine their relevance in developing interventions aimed at preventing childhood obesity.The scoping review was guided and informed by the Arksey and O'Malley (2005) framework. A systematic search was performed in four databases. Studies included in the final review were collated and sorted into relevant themes. A systematic search yielded a total of 5831 records (MEDLINE: 1242, EMBASE: 2629, CINAHL: 820, PubMed: 1140). Results without duplicates (n = 4190) were screened based on relevancy of which 197 relevant-full-text articles were retrieved and assessed for eligibility resulting in 14 studies meeting the inclusion criteria. Data were extracted and charted for the studies and six themes were identified: (1) healthy behaviors, lifestyle, and social economic status; (2) parental anthropometrics and perinatal weight status; (3) genetics, epigenetics, and fetal programming; (4) early infant feeding; (5) infant growth trajectories; and (6) targeted prevention and interventions. Early life risk factors for child obesity are multifactorial and potentially modifiable. Several at-risk groups were identified who would benefit from early preventative interventions targeting the importance of healthy weight gain, exclusive breastfeeding to 6 months, and healthy lifestyle behaviors.

Prenatal Exposure to Persistent Organic Pollutants and Changes in Infant Growth and Childhood Growth Trajectories

Prenatal Exposure to Persistent Organic Pollutants and Changes in Infant Growth and Childhood Growth Trajectories

Prenatal and Postnatal Household Air Pollution Exposure and Infant Growth Trajectories: Evidence from a Rural Ghanaian Pregnancy Cohort.

Background:The exposure–response association between prenatal and postnatal household air pollution (HAP) and infant growth trajectories is unknown.Objectives:To evaluate associations between prenatal and postnatal HAP exposure and stove interventions on growth trajectories over the first year of life.Methods:The Ghana Randomized Air Pollution and Health Study enrolled pregnant women at gestation from Kintampo, Ghana, and randomized them to liquefied petroleum gas (LPG), improved biomass, or open fire (control) stoves. We quantified HAP exposure by repeated, personal prenatal and postnatal carbon monoxide (CO) and, in a subset, fine particulate matter [PM with an aerodynamic diameter of ()] assessments. Length, weight, mid-upper arm circumference (MUAC) and head circumference (HC) were measured at birth, 3, 6, 9, and 12 months; weight-for-age, length-for-age (LAZ), and weight-for-length (WLZ)-scores were calculated. For each anthropometric measure, we employed latent class growth analysis to generate growth trajectories over the first year of life and assigned each child to a trajectory group. We then employed ordinal logistic regression to determine associations between HAP exposures and growth trajectory assignments. Associations with stove intervention arm were also considered.Results:Of the 1,306 live births, 1,144 had valid CO data and anthropometric variables measured at least once. Prenatal HAP exposure increased risk for lower length [CO 1.17, 95% CI: 1.01, 1.35 per 1-ppm increase; 1.07, 95% CI: 1.02, 1.13 increase], lower LAZ -score (CO 1.15, 95% CI: 1.01, 1.32 per 1-ppm increase) and stunting (CO 1.25, 95% CI: 1.08, 1.45) trajectories. Postnatal HAP exposure increased risk for smaller HC (CO 1.09, 95% CI: 1.04, 1.13 per 1-ppm increase), smaller MUAC and lower WLZ-score ( 1.07, 95% CI: 1.00, 1.14 and 1.09, 95% CI: 1.01, 1.19 increase, respectively) trajectories. Infants in the LPG arm had decreased odds of having smaller HC and MUAC trajectories as compared with those in the open fire stove arm ( 0.58, 95% CI: 0.37, 0.92 and 0.45, 95% CI: 0.22, 0.90, respectively).Discussion:Higher early life HAP exposure (during pregnancy and through the first year of life) was associated with poorer infant growth trajectories among children in rural Ghana. A cleaner-burning stove intervention may have improved some growth trajectories. https://doi.org/10.1289/EHP8109

Statistical Models for Estimating Linear Growth Velocity

Poor linear growth among infants is still a global public health issue. Linear growth velocity has been variously suggested as a more robust measure for growth over the classical measure of attained height for age. In this study, we systematically reviewed available literature for models used in estimating linear growth velocity. We searched Medline, Embase, Cochrane methodology register, Joanna Briggs Institute EBP, through the Ovid interface, and PubMed database to identify relevant articles that used statistical models to estimate linear growth velocity among infants. Longitudinal studies published in English were included. Two reviewers independently screened the titles and abstracts to identify potentially eligible studies. Any disagreements were discussed and resolved. Full-text articles were downloaded for all the studies that met the eligibility criteria. We synthesized literature using the preferred reporting items for systematic review and meta-analyses guidelines for the most used statistical methods for modelling infant growth trajectories. A total of 301 articles were retrieved from the initial search. Fifty-six full-text articles were assessed for eligibility and 16 of which were included in the final review with a total of 303,940 infants, median sample size of 732 (interquartile range: 241–1683). Polynomial function models were the most used growth model. Three (18.8%) of the articles modelled the linear growth. Two (12.5%) articles used mixed-effects models and another two (12.5%) used the Jenss-Bayley growth models to model linear growth. Other models included residual growth model, two-stage multilevel linear spline model, joint multilevel linear spline model, and generalized least squares with random effects. We have identified linear mixed-effects models, polynomial growth models, and the Jenss-Bayley model as the used models for characterizing linear growth among infants. Linear mixed-effects model is appealing for its robustness even under violation of largely robust even to quite severe violations of model assumptions.

Prenatal Air Pollution Exposure and Longitudinal Infant Weight Gain Trajectories

BACKGROUND AND AIM: The prenatal period may play a critical role in childhood obesity development. We examined the association between prenatal nitrogen oxides (NOx) and nitrogen dioxide (NO2) exposure and weight trajectories from birth to 2-years-of-age among infants in the Maternal and Development Risks from Environmental and Social Stressors (MADRES) pregnancy cohort. METHODS: Participants were enrolled during pregnancy and their children were followed up to 2 years. Anthropometric measurements were collected using a combination of medical record abstractions and study-staff measurements (n=471 participants; n=4,287 observations). Residential exposure to NOx and NO2 were estimated as: 1) spatial interpolation from air quality monitoring stations (daily NO2, ambient background), 2) CALINE4 line source dispersion modeled contribution from nearby roadways (daily NOx, traffic-related), and predictions from a machine-learning based spatiotemporal model (weekly NO2 and NOx, R2=0.87, RMSE=2.80 ppb). Exposures were averaged across pregnancy accounting for variable gestation lengths. Sex-stratified quadratic growth curve models were used to assess the association between prenatal NO2/NOx exposure and infant weight trajectories. RESULTS:Prenatal spatiotemporal model predicted NO2 exposure was associated with infant growth trajectories for both sexes. Infants experienced the most rapid growth early on with an average deceleration in weight gain of 0.02 grams/day over the two-year period. Among females (n=243), a 1-SD increase (3.3 ppb) in NO2 exposure was significantly associated with growth acceleration of 0.001 grams/day (p=0.02) such that at 2-years-of-age, children exposed to higher prenatal NO2 weighed significantly more than lower-exposed individuals. Among males (n=228), the linear and quadratic parameters of growth were both statistically significant. However, by 2 years the trajectories converged and no significant differences in weight were observed. We found similar trends when examining NOx and ambient NO2 exposures. CONCLUSIONS:Our findings show prenatal NO2/ NOx exposure may play a role in childhood obesity, with more pronounced effects on weight gain in females. KEYWORDS: Air pollution, oxides of nitrogen, birth outcomes, children's environmental health

Infant feeding and growth trajectories in early childhood: the application and comparison of two longitudinal modelling approaches.

The role of infant feeding practices in longitudinal growth trajectories in children remains equivocal. This study utilised two longitudinal approaches to examine the associations of infant feeding mode (breastfeeding, mixed feeding, formula feeding), breastfeeding duration, and the timing of solid foods introduction with body mass index (BMI) z-score in early childhood. Secondary analyses of data from the Healthy Beginnings Trial were conducted. Infant feeding practices were reported by mothers at 6, 12, and 24 months of child age. Child weight and length were measured at birth, 12, 24, 42, and 60 months. Two longitudinal approaches: linear spline multilevel model (LSMM) and group-based trajectory modelling (GBTM) were used to describe BMI z-score trajectories and assess its associations with infant feeding practices. The LSMM approach demonstrated that the breastfeeding group showed lower BMI z-scores from ages 12 to 60 months than the mixed feeding and formula feeding groups. Children who were breastfed for ≥ 6 versus < 6 months exhibited a lower BMI z-score trajectory from ages 12 to 60 months. Results from the GBTM approach revealed that the mixed feeding (OR: 1.83, 95%CI 1.04, 3.21) and the formula feeding group (OR: 2.00, 95%CI 0.67, 5.92) showed a tendency for higher odds of following the "High BMIz" trajectory than the breastfeeding group. Breastfeeding duration ≥6 versus < 6 months was linked with lower odds of following the "High BMIz" trajectory (OR 0.65, 95%CI 0.43, 0.98). Both approaches revealed no evidence of an association between the timing of solid foods introduction and BMI z-score trajectory. The two longitudinal approaches revealed similar findings that infant feeding mode and breastfeeding duration, but not the timing of solid foods introduction, were associated with BMI z-score trajectory in early childhood. The findings provide robust longitudinal evidence to encourage and support extended breastfeeding for childhood obesity prevention.

Growth patterns and clinical outcomes in association with breastfeeding duration in HIV exposed and unexposed infants: a cohort study in KwaZulu Natal, South Africa

BackgroundExclusive breastfeeding for 6 months and breastfeeding with complementary feeds until 12 months for HIV exposed and uninfected (HEU) infants or 24 months for HIV unexposed (HU) infants is the current World Health Organisation (WHO) recommendation for low and middle income countries (LMICs) to improve clinical outcomes and growth trajectories in infants. In a post-hoc evaluation of HEU and HU cohorts, we examine growth patterns and clinical outcomes in the first 9 months of infancy in association with breastfeeding duration.MethodsTwo cohorts of infants, HEU and HU from a low-socioeconomic township in South Africa, were evaluated from birth until 9 months of age. Clinical, anthropometric and infant feeding data were analysed. Standard descriptive statistics and regression analysis were performed to determine the effect of HIV exposure and breastfeeding duration on growth and clinical outcomes.ResultsIncluded in this secondary analysis were 123 HEU and 157 HU infants breastfed for a median of 26 and 14 weeks respectively. Median WLZ score was significantly (p < 0.001) lower in HEU than HU infants at 3, 6 and 9 months (− 0.19 vs 2.09; − 0.81 vs 0.28; 0.05 vs 0.97 respectively). The median LAZ score was significantly lower among HU infants at 3 and 6 months (− 1.63 vs 0.91, p < 0.001; − 0.37 vs 0.51, p < 0.01) and a significantly higher proportion of HU was classified as stunted (LAZ < -2SD) at 3 and 6 months (3.9% vs 44.9%, p < 0.001; 4.8% vs 20.9%, p < 0.001 respectively) independent of breastfeeding duration. A higher proportion of HEU infants experienced one or more episodes of skin rash (44.5% vs 12.8%) and upper respiratory tract infection (URTI) (30.1% vs 10.9%) (p < 0.0001). In a multivariable analysis, the odds of occurrence of wasting, skin rash, URTI or any clinical adverse event in HEU infants were 2.86, 7.06, 3.01 and 8.89 times higher than HU infants after adjusting for breastfeeding duration.ConclusionOur study has generated additional evidence that HEU infants are at substantial risk of infectious morbidity and decreased growth trajectories however we have further demonstrated that these adverse outcomes were independent of breastfeeding duration.

Different Blood Metabolomics Profiles in Infants Consuming a Meat- or Dairy-Based Complementary Diet

Background: Research is limited in evaluating the mechanisms responsible for infant growth in response to different protein-rich foods; Methods: Targeted and untargeted metabolomics analysis were conducted on serum samples collected from an infant controlled-feeding trial that participants consumed a meat- vs. dairy-based complementary diet from 5 to 12 months of age, and followed up at 24 months. Results: Isoleucine, valine, phenylalanine increased and threonine decreased over time among all participants; Although none of the individual essential amino acids had a significant impact on changes in growth Z scores from 5 to 12 months, principal component heavily weighted by BCAAs (leucine, isoleucine, valine) and phenylalanine had a positive association with changes in length-for-age Z score from 5 to 12 months. Concentrations of acylcarnitine-C4, acylcarnitine-C5 and acylcarnitine-C5:1 significantly increased over time with the dietary intervention, but none of the acylcarnitines were associated with infant growth Z scores. Quantitative trimethylamine N-oxide increased in the meat group from 5 to 12 months; Conclusions: Our findings suggest that increasing total protein intake by providing protein-rich complementary foods was associated with increased concentrations of certain essential amino acids and short-chain acyl-carnitines. The sources of protein-rich foods (e.g., meat vs. dairy) did not appear to differentially impact serum metabolites, and comprehensive mechanistic investigations are needed to identify other contributors or mediators of the diet-induced infant growth trajectories.