Association of birth mode of delivery with infant faecal microbiota, potential pathobionts, and short chain fatty acids: a longitudinal study over the first year of life.

OBJECTIVE: Caesarean section (CS) interrupts mother-to-newborn microbial transfer at birth. Beyond the neonatal period, the impact of CS on offspring gut microbiota and their short-chain fatty acids (SCFAs) remains unclear. Here, we examine birth delivery mode (CS versus vaginal delivery) with the infant gut microbiota and faecal SCFAs measured 3 and 12 months after birth. DESIGN: Longitudinal study. SETTING: North Carolina. POPULATION: In 2013-15, we enrolled pregnant women and followed up their offspring for 12 months. We asked a subset of participants, enrolled over a 3-month period, to provide faecal samples at the 3- and 12-month follow-up visits. METHODS AND MAIN OUTCOMES: We sequenced the 16S rRNA V4 region with Illumina MiSeq and quantified SCFA concentrations using gas chromatography. We examined delivery mode with differential abundance of microbiota amplicon sequence variants (ASVs) using beta-binomial regression and faecal SCFAs using linear regression. We adjusted models for confounders. RESULTS: Of the 70 infants in our sample, 25 (36%) were delivered by CS. Compared with vaginal delivery, CS was associated with differential abundance of 14 infant bacterial ASVs at 3 months and 13 ASVs at 12 months (all FDR P < 0.05). Of note, CS infants had a higher abundance of the potential pathobionts Clostridium neonatale (P = 0.04) and Clostridium perfringens (P = 0.04) and a lower abundance of potentially beneficial Bifidobacterium and Bacteroides spp. (both P < 0.05) at 3 months. Other ASVs were differentially abundant at 12 months. Infants delivered by CS also had higher faecal butyrate concentration at 3 months (P < 0.005) but not at 12 months. CONCLUSIONS: Caesarean section was associated with increased butyrate excretion, decreased Bifidobacterium and Bacteroides spp., and more colonisation of the infant gut by pathobionts at 3 months of age. CS was also associated with altered gut microbiota composition, but not faecal SCFAs, at 12 months. TWEETABLE ABSTRACT: Caesarean section delivery was associated with increased butyrate excretion, decreased Bifidobacterium, and increased colonisation of the infant gut by pathobionts at 3 months of age.

Household chaos during infancy and infant weight status at 12 months.

BACKGROUND: Infancy is a critical period for obesity prevention. Emerging evidence links household chaos to poor health outcomes, yet its impact on obesity in infancy is unknown. OBJECTIVES: We examined associations between household chaos when infants were 6 and 12 months and weight-for-length (WFL) z-score at 12 months, exploring potential mediation by infant sleep and screen time. METHODS: We examined 401 predominately Black women and infants in the southeastern United States. We conducted multivariable linear regressions examining household chaos and infant WFL z-score, assessing breastfeeding, sleep, screen time as potential mediators. RESULTS: Among infants, 69.7% were Black and 49.0% were female. Mean breasting duration was 3.7 months. Over half (50.4%) of families had annual household incomes <$20 000. After adjustment for potential confounders, household chaos was associated with infant WFL z-score (0.02; 95% CI 0.001, 0.04; p = 0.04) at 12 months. We did not observe associations between chaos and infant breastfeeding, sleep or screen time. CONCLUSIONS: Higher household chaos was associated with greater infant weight at 12 months, but there was no evidence of mediation by breastfeeding, sleep or screen time.

Childcare before age 6 and body mass index at age 7 years in a cohort of Danish children.

BACKGROUND: Previous studies show inconsistent associations between childcare and obesity. AIMS: Our prior work demonstrated that childcare in infancy was associated with higher weight in a cohort of Danish children. Here, we extend this work and examine childcare through 6 years and body mass index (BMI) at age 7 years. MATERIALS AND METHODS: We examined 24 714 children in the Danish National Birth Cohort who were also in the Childcare Database. We conducted multivariable linear regressions examining children prior to age 6, overall and by type (daycare, crèche, age-integrated and kindergarten), and BMI z-score at 7 years, stratifying on maternal socio-occupational status. RESULTS: A total of 19 760 (80.0%) children attended childcare before age 6. Childcare prior to age 6 was associated with BMI z-score at 7 years (0.004 units per each additional 6 months of care; 95% CI: 0.001, 0.008; p = 0.01). Childcare in a kindergarten was the only type of care associated with BMI (0.009 units; 95% CI: 0.003, 0.02; p = 0.01). For children of higher socio-occupational status mothers, childcare was associated with a 0.008 unit increase in BMI (95% CI: 0.004, 0.01; p > 0.001). CONCLUSIONS: Childcare was weakly associated with later BMI. This relationship was more pronounced in children from higher socio-occupational status mothers and children in kindergarten care.

Maternal vitamin D, DNA methylation at imprint regulatory regions and offspring weight at birth, 1 year and 3 years.

BACKGROUND/OBJECTIVE: Vitamin D deficiency during pregnancy is associated with poor birth outcomes in some studies, but few have examined weight beyond birth. In addition, little is known about how vitamin D influences DNA methylation of regulatory regions known to be involved in growth, as possible mediators to weight status in offspring. SUBJECTS/METHODS: We conducted linear regressions to assess maternal plasma 25-hydroxyvitamin D (25(OH)D) by quartile and birth weight for gestational age z-score, 1-year weight-for-length z-score and 3-year body mass index (BMI) z-score among 476 mother/infant dyads from a prospective cohort. We assessed maternal 25(OH)D and infant DNA methylation at nine differentially methylated regions (DMRs) of genomically imprinted genes with known functions in fetal growth, including H19, IGF2, MEG3, MEG3-IG, MEST, NNAT, PEG3, PLAGL1 and SGCE/PEG10. RESULTS: Mean (standard deviation, s.d.) maternal 25(OH)D was 41.1 (14.2) nmol l-m at a mean (s.d.) of 13.2 (5.5) weeks gestation. After adjustment for potential confounders, the first (Q1) and second (Q2) quartiles of 25(OH)D, compared to the fourth (Q4), were associated with lower birth weight for gestational age z-scores (-0.43 units; CI: -0.79, -0.07; P=0.02 for Q1 and -0.56 units; CI: -0.89, -0.23; P=0.001 for Q2). Q1 compared to Q4 was associated with higher 1-year weight-for-length z-scores (0.78 units; 0.08, 1.54; P=0.04) and higher 3-year BMI z-scores (0.83 units; 0.11, 0.93; P=0.02). We did not observe associations between maternal 25(OH)D and methylation for any of the nine DMRs after correcting for multiple testing. CONCLUSIONS: Reduced maternal 25(OH)D was associated with lower birth weight for gestational age z-scores but higher 1-year weight-for-length and 3-year BMI z-scores in offspring. However, 25(OH)D does not appear to be operating through the regulatory sequences of the genomically imprinted genes we examined.

Preventing childhood obesity in early care and education settings: lessons from two intervention studies.

BACKGROUND: Obesity prevention in young children is a public health priority. In the USA, nearly 10% of children less than 5 years of age are obese, and most attend some form of out-of-home child care. While a number of interventions have been conducted in early care and education settings, few have targeted the youngest children in care or the less formal types of child care like family child care homes. Additionally, only two previous studies provided recommendations to help inform future interventions. METHODS: This paper presents lessons learned from two distinct intervention studies in early care and education settings to help guide researchers and public health professionals interested in implementing and evaluating similar interventions. We highlight two studies: one targeting children ages 4 to 24 months in child care centres and the other intervening in children 18 months to 4 years in family child care homes. We include lessons from our pilot studies and the ongoing larger trials. RESULTS: To date, our experiences suggest that an intervention should have a firm basis in behaviour change theory; an advisory group should help evaluate intervention materials and plan for delivery; and realistic recruitment goals should recognize economic challenges of the business of child care. A flexible data collection approach and realistic sample size calculations are needed because of high rates of child (and sometimes facility) turnover. An intervention that is relatively easy to implement is more likely to appeal to a wide variety of early care and education providers. CONCLUSIONS: Interventions to prevent obesity in early care and education have the potential to reach large numbers of children. It is important to consider the unique features and similarities of centres and family child care homes and take advantage of lessons learned from current studies in order to develop effective, evidence-based interventions.

Early child care and obesity at 12 months of age in the Danish National Birth Cohort.

BACKGROUND/OBJECTIVES: Evidence suggests that the child care environment may be more obesogenic than the family home, and previous studies have found that child care use may be associated with obesity in children. Few studies, however, have focused on child care during infancy, which may be an especially vulnerable period. This study examined child care use in infancy and weight status at 12 months of age in a country where paid maternity leave is common and early child care is not as prevalent as in other developed countries. SUBJECTS/METHODS: We studied 27,821 children born to mothers participating in the Danish National Birth Cohort, a longitudinal study of pregnant women enrolled between 1997 and 2002, who were also included in the Childcare Database, a national record of child care use in Denmark. The exposure was days in child care from birth to 12 months. The outcomes were sex-specific body mass index (BMI) z-score and overweight/obesity (BMI ⩾ 85th percentile based on the World Health Organization classification) at 12 months. We conducted multivariable linear and logistic regression analyses examining child care use and weight outcomes. RESULTS: A total of 17,721 (63.7%) children attended child care during their first year of life. After adjustment for potential confounders, a 30-day increment of child care was associated with a modestly higher BMI z-score at 12 months (0.03 units; 95% confidence interval (CI) = 0.01, 0.05; P=0.003). Similarly, child care use was associated with increased odds of being overweight/obese at 12 months of age (odds ratio = 1.05; 95% CI = 1.01, 1.10; P=0.047). CONCLUSION: Child care in the first year of life was associated with slightly higher weight at 12 months, suggesting that child care settings may be important targets for obesity prevention in infancy.

Promoting breastfeeding in child care through state regulation.

Policies supporting breastfeeding vary by state, but little is known about the geographical aspects of this variation. This study describes state breastfeeding licensing and administrative regulations targeting child care settings, compares regulations with national standards, and examines the spatial patterning and clustering of these regulations throughout the United States (US). We compared regulations for child care centers (centers) and family child care homes (homes) with national standards for: (1) general breastfeeding support; (2) designated place for breastfeeding; (3) no solids before infants are four months of age; and (4) no formula for breastfed infants without parent permission. We scored state regulations as 0 = standard not addressed, 1 = standard partially addressed, and 2 = standard fully addressed. We considered each regulation individually, and also summed scores to provide an overall rating of regulations by state. We mapped regulations using geographic information systems technology, and explored overall and local spatial autocorrelation using global and local variants of Moran's I. Five states had regulations for centers and two for homes that addressed all four standards. Mean regulation scores were 0.35, 0.20, 0.98, 0.74 for centers, and 0.17, 0.15, 0.79, 0.58 for homes. Local Moran's I revealed that New York and Pennsylvania had substantially stronger regulations than their adjacent states, while Florida had weaker regulations than its neighbors. Overall, few states had regulations that met breastfeeding standards. We identified some patterns of spatial correlation, suggesting avenues for future research to better understand distributions of regulations across the US.