Metal availability shapes early life microbial ecology and community succession.

The gut microbiota plays a critical role in human health and disease. Microbial community assembly and succession early in life are influenced by numerous factors. In turn, assembly of this microbial community is known to influence the host, including immune system development, and has been linked to outcomes later in life.

A comparison of ultrasound-based testis volume with Prader orchidometry and stability of testis size relative to peers from birth to 28 weeks.

Background: Testis volume, an indicator of the reproductive development during minipuberty, is commonly measured by Prader orchidometer, despite ultrasound being the gold standard. Data are lacking on the longitudinal relationship between these two measures and on the stability of boys' relative testis size across infancy.

Objectives: To examine the relationship between ultrasound-based and orchidometer-based testis volume measurements and to assess the stability of relative testis size among individual boys in the study.

Environmental Phenols and Growth in Infancy: The Infant Feeding and Early Development Study.

Context: Higher mean and rapid increases in body mass index (BMI) during infancy are associated with subsequent obesity and may be influenced by exposure to endocrine-disrupting chemicals such as phenols.

Objective: In a prospective US-based cohort conducted 2010-2014, we investigated associations between environmental phenol exposures and BMI in 199 infants.

Methods: We measured 7 urinary phenols at ages 6-8 and 12 weeks and assessed BMI z-score at up to 12 study visits between birth and 36 weeks.

Environmental phenol exposures in 6- to 12-week-old infants: The Infant Feeding and Early Development (IFED) study.

Background: Exposure to phenols, endocrine-disrupting chemicals used in personal care and consumer products, is widespread. Data on infant exposures are limited despite heightened sensitivity to endocrine disruption during this developmental period. We aimed to describe distributions and predictors of urinary phenol concentrations among U.

African American mothers' perceptions of infant body size are prospectively associated with infant growth and BMI.

Objectives: The effect of mothers' perceptions of infant body size on infant growth and later BMI is poorly understood. We aimed to assess whether maternal perceptions were associated with infant BMI and weight gain and to identify factors that may influence maternal perceptions.

Methods: We analyzed data from a prospective, longitudinal study of pregnant African American women living with healthy weight (BMI < 25 kg/m ) or obesity (BMI ≥ 30 kg/m ).

Reproductive Hormone Concentrations and Associated Anatomical Responses: Does Soy Formula Affect Minipuberty in Boys?

Context: Soy formula feeding is common in infancy and is a source of high exposure to phytoestrogens, documented to influence vaginal cytology in female infants. Its influence on minipuberty in males has not been established.

Objective: To assess the association between infant feeding practice and longitudinally measured reproductive hormones and hormone-responsive tissues in infant boys.

The stepwise assembly of the neonatal virome is modulated by breastfeeding.

The gut of healthy human neonates is usually devoid of viruses at birth, but quickly becomes colonized, which-in some cases-leads to gastrointestinal disorders. Here we show that the assembly of the viral community in neonates takes place in distinct steps. Fluorescent staining of virus-like particles purified from infant meconium or early stool samples shows few or no particles, but by one month of life particle numbers increase to 10 per gram, and these numbers seem to persist throughout life.

Endocrine-sensitive physical endpoints in newborns: ranges and predictors.

Background: In neonates, endocrine-sensitive physical endpoints, including breast and reproductive tissues, may reflect effects of fetal environmental exposure. Studies using standardized measurement techniques that describe demographic and clinical variability in these endpoints are lacking.

Methods: Three hundred and eighty-eight healthy term newborns <3 days old were evaluated, 69% African American and 25% White.

Characterization of ovarian development in girls from birth to 9 months.

Background: The minipuberty of infancy is a period of increased reproductive axis activity. Changes in reproductive hormone concentrations and organ size occur during this period, but longitudinal changes have not been well described.

Objectives: The objective of this study was to characterize ovarian growth trajectories and ovarian follicle development during the first 9 months of life in a large longitudinal cohort of healthy girls.

Bacterial colonization reprograms the neonatal gut metabolome.

Initial microbial colonization and later succession in the gut of human infants are linked to health and disease later in life. The timing of the appearance of the first gut microbiome, and the consequences for the early life metabolome, are just starting to be defined. Here, we evaluated the gut microbiome, proteome and metabolome in 88 African-American newborns using faecal samples collected in the first few days of life.

Incidental findings during ultrasound of thyroid, breast, testis, uterus and ovary in healthy term neonates.

Incidental sonographic findings in thyroid and estrogen-responsive organs have been described in children and adults, but no publications describe incidental findings of these organs in infancy. We describe ultrasound features in thyroid, breast buds, testes, uterus, and ovaries in infants up to 32 weeks old that vary from the expected tissue architecture. Infants described in this paper were enrolled as healthy term neonates in a longitudinal study of normal feeding practices.

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.

A Longitudinal Study of Estrogen-Responsive Tissues and Hormone Concentrations in Infants Fed Soy Formula.

Purpose: Chemicals with hormonelike activity, such as estrogenic isoflavones, may perturb human development. Infants exclusively fed soy-based formula are highly exposed to isoflavones, but their physiologic responses remain uncharacterized. Estrogen-responsive postnatal development was compared in infants exclusively fed soy formula, cow-milk formula, and breast milk.

Size of testes, ovaries, uterus and breast buds by ultrasound in healthy full-term neonates ages 0-3 days.

Background: Hormonally sensitive organs in the neonate can change size within days of birth as circulating maternal estrogen wanes. Although several reports document the size of these organs through infancy, few focus attention on the near-birth period. Clinical and research evaluation of hormonal and genitourinary disorders would benefit from reference size standards.

Student public commitment in a school-based diabetes prevention project: impact on physical health and health behavior.

Background: As concern about youth obesity continues to mount, there is increasing consideration of widespread policy changes to support improved nutritional and enhanced physical activity offerings in schools. A critical element in the success of such programs may be to involve students as spokespeople for the program. Making such a public commitment to healthy lifestyle program targets (improved nutrition and enhanced physical activity) may potentiate healthy behavior changes among such students and provide a model for their peers.