Prenatal and postnatal energetic conditions and sex steroids levels across the first year of life

Breastfeeding and ApoB in late adolescence: a Hong Kong birth cohort study

Breastfeeding is widely promoted. Experimental evidence concerning long-term benefits is limited. Observational studies are open to bias from confounding by socio-economic position. We assessed the association of breastfeeding with late adolescent lipid sub-fractions, particularly apolipoprotein B (ApoB) and non-high-density lipoprotein cholesterol (non-HDL-c), overall and by sex. We took advantage of a setting where breastfeeding has little association with higher socio-economic position and where several results from randomized controlled trials of breastfeeding promotion have been replicated. We used the population-representative "Children of 1997" birth cohort comprising 88% of births in Hong Kong in April and May 1997. Associations of breastfeeding in the first 3 months of life (never, mixed, exclusive) with lipid sub-fractions were obtained using linear regression adjusted for potential confounders including parental socio-economic position, maternal place of birth, type of delivery, gestational age, and birth weight. Differences by sex were assessed. Multiple imputation and inverse probability weighting were used to recover the original sample. Of the 3462 participants included, mean age was 17.6 years and 48.8% were girls. Mean ApoB was 0.74 g/L (standard deviation 0.15). Exclusive versus never breastfeeding was associated with lower ApoB (-0.027 g/L, 95% confidence interval (CI)-0.046 to-0.007, p = 0.007) and lower non-HDL-c (-0.143 mmol/L, 95% CI-0.237 to-0.048) with similar estimates by sex.

CONCLUSION

Breastfeeding may provide some population-level lifelong protection against cardiovascular disease. This study supports policies promoting breastfeeding as a modifiable exposure that contributes to a healthy start in life as an investment for lifelong cardiovascular disease prevention.

WHAT IS KNOWN

• Apolipoprotein B (ApoB) is a recognized risk factor for cardiovascular disease, but whether breastfeeding affects ApoB in later life overall and by sex is unknown.

WHAT IS NEW

• Exclusive breastfeeding in the first 3 months of life was associated with lower ApoB in late adolescence, with similar estimates for both sexes. • The inverse association of breastfeeding with ApoB suggests that breastfeeding could reduce cardiovascular disease and overall mortality over the lifespan.

Oestrogens and progesterone in human milk and their effects on infant health outcomes: A narrative review

Human milk (HM) is a complex biological system that contains a wide range of bioactive components including oestrogens and progesterone. Whilst maternal oestrogens and progesterone concentrations drop rapidly after birth, they remain detectable in HM across lactation. Phytoestrogens and mycoestrogens, which are produced by plants and fungi, are also present in HM and can interact with oestrogen receptors to interfere with normal hormone functions. Despite the potential impact of HM oestrogens and progesterone on the infant, limited research has addressed their impact on the growth and health of breastfed infants. Furthermore, it is important to comprehensively understand the factors that contribute to these hormone levels in HM, in order to establish effective intervention strategies. In this review, we have summarized the concentrations of naturally occurring oestrogens and progesterone in HM from both endogenous and exogenous sources and discussed both maternal factors impacting HM levels and relationships with infant growth.

Minimally invasive biomarkers in human and non-human primate evolutionary biology: Tools for understanding variation and adaptation

BACKGROUND

The use of minimally invasive biomarkers (MIBs - physiological biomarkers obtained from minimally invasive sample types) has expanded rapidly in science and medicine over the past several decades. The MIB approach is a methodological strength in the field of human and non-human primate evolutionary biology (HEB). Among humans and our closest relatives, MIBs provide unique opportunities to document phenotypic variation and to operationalize evolutionary hypotheses.

AIMS

This paper overviews the use of MIBs in HEB. Our objectives are to (1) highlight key research topics which successfully implement MIBs, (2) identify promising yet under-investigated areas of MIB application, and (3) discuss current challenges in MIB research, with suggestions for advancing the field.

DISCUSSION AND CONCLUSIONS

A range of MIBs are used to investigate focal topics in HEB, including energetics and life history variation/evolution, developmental plasticity, and social status and dominance relationships. Nonetheless, we identify gaps in existing MIB research on traits such as physical growth and gut function that are central to the field. Several challenges remain for HEB research using MIBs, including the need for additional biomarkers and methods of assessment, robust validations, and approaches that are standardized across labs and research groups. Importantly, researchers must provide better support for adaptation and fitness effects in hypothesis testing (e.g., by obtaining complementary measures of energy expenditure, demonstrating redundancy of function, and performing lifetime/longitudinal analyses). We point to continued progress in the use of MIBs in HEB to better understand the past, present, and future of humans and our closest primate relatives.

Minipuberty in born small for gestational age infants: A case control prospective pilot study

PURPOSE

To evaluate minipuberty (MP) in small for gestational age (SGA) infants, both preterm and full-term, during the first year of life.

METHODS

33 SGA healthy newborns (group A), 21 of which full-term (subgroup A1) and 12 preterm (A2) were enrolled. Control group (B) consisted of 27 AGA, 17 full-term (subgroup B1) and 10 preterm (B2) infants. Growth parameters, FSH, LH, and Estradiol (E2) or Testosterone (T) serum levels were monitored at 3, 6, and 12 months.

RESULTS

The gonadotropin surge reached greater increase of LH in males at 3 months and FSH in females at 3, 6 and 12 months (p < 0.001). In male infants: T at 3 months was higher in subgroup A2 vs A1(p = 0.001), and correlated negatively with gestational age (GA, p < 0.005), length and weight at birth (p < 0.05); LH was higher in subgroup B2 vs B1 at 6 months (p = 0.003), and in group A vs B at 12 months (p = 0.03). Females displayed higher E2 at 6 months in B2 vs B1 (p < 0.05), negatively correlated with GA and weight gain (p < 0.05); LH at 6 months was increased in A2 vs A1 (p = 0.03). Overall, preterm males displayed higher T at 3 months (p = 0.001), LH at 3, 6 and 12 months (p < 0.05), and LH/FSH ratio at 6 months (p = 0.001). Preterm females exhibited increased LH/FSH ratio at 3 and 6 months (p < 0.05).

CONCLUSIONS

Irrespectively of GA, MP occurred with a typical sexual dimorphism and exhibited sex-specific correlations between hormones and perinatal parameters. SGA condition and prematurity seemed to enhance and protract MP over time in both sexes.

Greater male vulnerability to stunting? Evaluating sex differences in growth, pathways and biocultural mechanisms

CONTEXT

Child stunting has increasingly become the focus of large-scale global health efforts with the inclusion of stunting eradication as one of the Sustainable Development Goals of the United Nations. Child sex has been identified as a biological risk factor for stunting, and sex-specific approaches to stunting prevention have been proposed.

OBJECTIVE

This paper examines four pathways, developmental sensitivity, energetics, caretaking and measurement, proposed to contribute to sex differences in linear growth faltering and stunting risk.

METHODS

Anthropological, public health and clinical literature on sex differences in stunting and the mechanisms contributing to variability across contexts are reviewed.

RESULTS

The direction of sex differences in stunting prevalence varies across countries and between households. Sex differences in growth trajectories and immune function beginning prenatally place boys at greater risk of infection and undernutrition, but these biological differences are interpreted by parents and within household contexts that are shaped by social and cultural norms which, in turn, influence care and feeding practices.

CONCLUSION

A perspective that incorporates an examination of the social and environmental factors shaping child growth in specific contexts is needed to understand sex-based vulnerability to stunting and to develop context-appropriate interventions.

Maternal high-protein diet modulates hepatic growth axis in weaning piglets by reprogramming the IGFBP-3 gene

PURPOSE

The aim of this study was to investigate the effects of maternal high dietary protein intake on the hepatic growth axis in offspring.

METHODS

Fourteen primiparous purebred Meishan sows were fed either a standard-protein (SP, n = 7) diet or a high-protein (HP, 150% of SP, n = 7) diet during pregnancy. Offspring (one male and one female per group, n = 14) on day 70 of the embryonic stage and on days 1, 35 and 180 after birth were selected, weighed and killed. Serum samples were analyzed for Tch, insulin and insulin-like growth factor-binding protein 3 (IGFBP-3) levels. Liver samples were analyzed for IGFBP-3 and IGF-I mRNA expression by qRT-PCR and for IGFBP-3, IGF1R and growth hormone receptor (GHR) protein expression by Western blotting. The underlying mechanism of IGFBP-3 regulation was determined by methylated DNA immunoprecipitation (MeDIP) and chromatin immunoprecipitation (ChIP).

RESULTS

High-protein exposure resulted in significantly higher body and liver weights of piglets, and it increased their serum T3 and T4 levels at birth and/or at weaning. Furthermore, the IGFBP-3 protein content in the liver and serum was significantly reduced in the HP-exposed weaning piglets, whereas at the transcriptional level IGFBP-3 mRNA expression was downregulated in the livers of HP group piglets. Finally, DNA hypermethylation and higher enrichment of the histone repressive marks H3K27me3 and H3K9me3 were observed.

CONCLUSIONS

Taken together, these results suggest that a maternal high-protein diet during gestation epigenetically reprograms IGFBP-3 gene expression to modulate the hepatic growth axis in weaning piglets.

Evaluation of fecal hormones for noninvasive research on reproduction and stress in humpback whales (Megaptera novaeangliae)

Fecal hormone analysis shows high potential for noninvasive assessment of population-level patterns in stress and reproduction of marine mammals. However, the marine environment presents unique challenges for fecal sample collection. Data are still lacking on collection methodology and assay validations for most species, particularly for those mysticete whales that have variable diets. In this study we tested collection techniques for fecal samples of free-swimming humpback whales (Megaptera novaeangliae), and validated immunoassays for five steroid and thyroid hormones. Resulting data were used for preliminary physiological validations, i.e., comparisons to independently confirmed sex and reproductive state. Pregnant females had significantly higher fecal progestins and glucocorticoids than did other demographic categories of whales. Two possible cases of previously undetected pregnancies were noted. Males had significantly higher fecal testosterone metabolites than nonpregnant females. Fecal glucocorticoids were significantly elevated in pregnant females and mature males compared to nonpregnant females. Calf fecal samples had elevated concentrations of all fecal hormones. Fecal thyroid hormones showed a significant seasonal decline from spring to summer. Though sample sizes were small, and sampling was necessarily opportunistic, these patterns indicate that noninvasive fecal hormone analysis may facilitate studies of reproduction, stress and potentially energetics in humpback whales.

Influence of early-life factors on the development of endometriosis

Objective: Our aim was to study the association between early-life factors and the development of endometriosis. Methods: This case-control study included 440 women with surgically confirmed endometriosis (cases) and 880 women without endometriosis (controls). Information on early-life factors was ascertained retrospectively by in-person interviews with participants and their mothers. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between endometriosis and maternal and paternal characteristics and foetal and infant exposures were estimated using unconditional logistic regression, adjusting for frequency matching and confounding variables. Results: We observed that women who were not breastfed as infants had twice the risk of endometriosis compared with women who were breastfed (adjusted OR 2.0; 95% CI 1.6, 4.5). Our data suggested an increased endometriosis risk with neonatal vaginal bleeding (adjusted OR 1.9; 95% CI 1.2, 4.3) and paternal smoking (adjusted OR 1.8; 95% CI 1.1, 4.9). Although the CIs included the null hypothesis value, caesarean section (adjusted OR 1.7; 95% CI 1.0, 3.5) and prematurity (adjusted OR 1.4; 95% CI 0.8, 3.7) were probably associated with the incidence of endometriosis. Conclusions: Some early-life factors including breastfeeding, neonatal vaginal bleeding and paternal smoking were associated with subsequent, surgically confirmed endometriosis in this cohort of Chinese women.

The Association of Infant Growth Patterns with Adiposity in Adolescence: Prospective Observations from Hong Kong's 'Children of 1997' Birth Cohort

BACKGROUND

The role of infant growth in adiposity remains unclear.

METHODS

We used multivariable linear regression, with inverse probability weighting and multiple imputation to account for loss to follow-up, in a population-representative Chinese birth cohort, 'Children of 1997' in Hong Kong, to examine, in terms births, the adjusted association of infant (birth to 12 months) weight growth trajectories with body mass index (BMI) (n = 6861, 88% follow-up), waist-to-height ratio (WHtR), and waist-to-hip ratio (WHR) (n = 5398, 69% follow-up) at ∼ 14 years.

RESULTS

Infant weight growth trajectories had graded associations with adolescent BMI and WHtR but not with WHR, such that compared with adolescents born light with slow infant growth, adolescents born heavy with fast infant growth had higher BMI z-score [0.60, 95% confidence interval (CI) 0.49, 0.70], higher WHtR z-score (0.17, 95% CI 0.08, 0.26) but similar WHR z-score (-0.02, 95% CI -0.11, 0.08), adjusted for sex, gestational age, parental education, parental BMI, parental height, and parental place of birth.

CONCLUSIONS

Varying associations of infant growth with different adiposity measures suggest a complex role of infant growth in long-term health, perhaps because infant growth, or its underlying drivers, influences build and body composition as well as adiposity.

Milk- and solid-feeding practices and daycare attendance are associated with differences in bacterial diversity, predominant communities, and metabolic and immune function of the infant gut microbiome

The development of the infant intestinal microbiome in response to dietary and other exposures may shape long-term metabolic and immune function. We examined differences in the community structure and function of the intestinal microbiome between four feeding groups, exclusively breastfed infants before introduction of solid foods (EBF), non-exclusively breastfed infants before introduction of solid foods (non-EBF), EBF infants after introduction of solid foods (EBF+S), and non-EBF infants after introduction of solid foods (non-EBF+S), and tested whether out-of-home daycare attendance was associated with differences in relative abundance of gut bacteria. Bacterial 16S rRNA amplicon sequencing was performed on 49 stool samples collected longitudinally from a cohort of 9 infants (5 male, 4 female). PICRUSt metabolic inference analysis was used to identify metabolic impacts of feeding practices on the infant gut microbiome. Sequencing data identified significant differences across groups defined by feeding and daycare attendance. Non-EBF and daycare-attending infants had higher diversity and species richness than EBF and non-daycare attending infants. The gut microbiome of EBF infants showed increased proportions of Bifidobacterium and lower abundance of Bacteroidetes and Clostridiales than non-EBF infants. PICRUSt analysis indicated that introduction of solid foods had a marginal impact on the microbiome of EBF infants (24 enzymes overrepresented in EBF+S infants). In contrast, over 200 bacterial gene categories were overrepresented in non-EBF+S compared to non-EBF infants including several bacterial methyl-accepting chemotaxis proteins (MCP) involved in signal transduction. The identified differences between EBF and non-EBF infants suggest that breast milk may provide the gut microbiome with a greater plasticity (despite having a lower phylogenetic diversity) that eases the transition into solid foods.

Infant BMI peak, breastfeeding, and body composition at age 3 y

BACKGROUND

With the increasing focus on obesity, growth patterns in infancy and early childhood have gained much attention. Although the adiposity rebound has been in focus because of a shown association with adult obesity, not much has been published about the infant peak in body mass index (BMI).

OBJECTIVE

This study links age and BMI at infant peak to duration of breastfeeding and body composition at 3 y of age.

DESIGN

Frequent weight and height measurements for 311 Danish children in the SKOT (Complementary and Young Child Feeding - Impact on Short and Long Term Development and Health; in Danish) cohort were used to estimate BMI growth curves for the age span from 14 d to 19 mo by using a nonlinear mixed-effects model. BMI growth velocity before peak and age and BMI at peak were derived from the subject-specific models. Information about pregnancy and breastfeeding was assessed from background questionnaires. Assessment of body composition at age 3 y was made based on bioelectrical impedance, weight, and height.

RESULTS

A longer duration of exclusive breastfeeding was associated with an earlier peak in infant BMI (P = 0.0003) and a lower prepeak velocity (P < 0.0001). BMI level at peak and prepeak velocity was positively associated with fat and fat-free mass at age 3 y (all P < 0.0001), whereas a later age at peak was associated with a lower fat mass, fat mass index, and fat-free mass index at age 3 y (all P < 0.001).

CONCLUSIONS

BMI peak characteristics are strongly associated with both duration of exclusive breastfeeding and body composition at 3 y of age. Thus, a better knowledge of characteristics and determinants of the early BMI peak is likely to improve our understanding of early development of obesity.