Breastfeeding during infancy and neurocognitive function in adolescence: 16-year follow-up of the PROBIT cluster-randomized trial

The relationships between optimal infant feeding practices and child development and attained height at age 2 years and 6-7 years

Limited evidence exists on the long-term effects of early feeding practices on child growth and development. We examined the relationships between infant feeding practices and child height and development at ages 2 and 6-7 years. We studied 885 mother-child dyads from a randomized controlled trial of preconception supplementation in Vietnam. Early initiation of breastfeeding (EIBF), exclusive breastfeeding (EBF), breastfeeding (BF) duration and minimum dietary diversity (MDD) were assessed using World Health Organization (WHO) guidelines. Child development was assessed by the Bayley Scales of Infant Development-III at 2 years and the Wechsler Intelligence Scale for Children® - IV at 6-7 years. Child height-for-age z-score (HAZ) was calculated from child height and age. Multivariable regression and structural equation models were used in analyses that controlled for confounding. EIBF and EBF at 6 months occurred in 52% and 62% of children, respectively. Mean breastfeeding duration was 18 months and 83% achieved MDD at 1 year. EIBF was associated with motor (β = 0.13, 95% confidence interval [CI]: 0.00, 0.28) and cognitive development at 2 years (β = 0.12, 95% CI: -0.01, 0.26), which in turn were positively associated with cognitive development at 6-7 years. EBF was directly associated with development at 6-7 years (β = 0.21, 95% CI:0.08, 0.34) whereas motor and cognitive development at 2 years explained 41%-75% of the relationship between EIBF and development at 6-7 years. HAZ at 2 years also mediated 70% of the association between MDD at 1 year and HAZ at 6-7 years. BF duration was not associated with child development and HAZ. Early infant feeding practices, especially EIBF and EBF, have important long-term implications for optimizing child linear growth and cognition as they begin school.

Co-benefits from health and health systems to education

This review draws on over 70 studies spanning 2000 to 2023 to analyze the causal effect of health on educational outcomes. Health and health system interventions during the prenatal, infant, and childhood period impact longer-run educational attainment and performance. The magnitude of these effects is both statistically and economically significant, comparable in size to impacts on educational outcomes of interventions found in the literature. These impacts of health and health system interventions differ across gender and socioeconomic status, illustrating how health and health systems can exacerbate or mitigate educational inequalities. By showing the intertwined nature of health and education, this review highlights the importance of a comprehensive approach in policy-making that aligns with the Sustainable Development Goals.

A Taxonomy of Non-honesty in Public Health Communication

This paper discusses the ethics of public health communication. We argue that a number of commonplace tools of public health communication risk qualifying as non-honest and question whether or not using such tools is ethically justified. First, we introduce the concept of honesty and suggest some reasons for thinking it is morally desirable. We then describe a number of common ways in which public health communication presents information about health-promoting interventions. These include the omission of information about the magnitude of benefits people can expect from health-promoting interventions, and failure to report uncertainty associated with the outcomes of interventions. Next we outline some forms of behaviour which are generally recognised by philosophers as being non-honest, including deception, manipulation, and so on. Finally, we suggest that many of the public health communicative practices identified earlier share features with the non-honest behaviours described and suggest this warrants reflection upon whether such non-honesty is justified by the goals of public health communication.

Breastfeeding duration is associated with larger cortical gray matter volumes in children from the ABCD study

BACKGROUND

Despite the numerous studies in favor of breastfeeding for its benefits in cognition and mental health, the long-term effects of breastfeeding on brain structure are still largely unknown. Our main objective was to study the relationship between breastfeeding duration and cerebral gray matter volumes. We also explored the potential mediatory role of brain volumes on behavior.

METHODS

We analyzed 7,860 magnetic resonance images of children 9-11 years of age from the Adolescent Brain Cognitive Development (ABCD) dataset in order to study the relationship between breastfeeding duration and cerebral gray matter volumes. We also obtained several behavioral data (cognition, behavioral problems, prodromal psychotic experiences, prosociality, impulsivity) to explore the potential mediatory role of brain volumes on behavior.

RESULTS

In the 7,860 children analyzed (median age = 9 years and 11 months; 49.9% female), whole-brain voxel-based morphometry analyses revealed an association mainly between breastfeeding duration and larger bilateral volumes of the pars orbitalis and the lateral orbitofrontal cortex. In particular, the association with the left pars orbitalis and the left lateral orbitofrontal cortex proved to be very robust to the addition of potentially confounding covariates, random selection of siblings, and splitting the sample in two. The volume of the left pars orbitalis and the left lateral orbitofrontal cortex appeared to mediate the relationship between breastfeeding duration and the negative urgency dimension of the UPPS-P Impulsive Behavior Scale. Global gray matter volumes were also significant mediators for behavioral problems as measured with the Child Behavior Checklist.

CONCLUSIONS

Our findings suggest that breastfeeding is a relevant factor in the proper development of the brain, particularly for the pars orbitalis and lateral orbitofrontal cortex regions. This, in turn, may impact impulsive personality and mental health in early puberty.

Breastfeeding in infancy and mortality in middle and late adulthood: A prospective cohort study and meta-analysis

BACKGROUND

Breastfeeding in infancy is associated with a lower risk of mortality among children, but the impact on mortality in middle and late adulthood remains unknown.

OBJECTIVES

To assess the association between breastfeeding in infancy and mortality in middle and late adulthood.

METHODS

We included 383,627 participants aged 40-73 from the UK Biobank (2006-2010) and followed up until 2021. Hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality according to breastfeeding in infancy were estimated with Cox proportional hazards regression models. We further did a meta-analysis, including results from our present study and three other cohort studies (PROSPERO; number CRD42022348925).

RESULTS

During a total of 4732,751 person-years of follow-up, 25,581 deaths were identified. Breastfeeding in infancy was associated with lower risks of mortality in middle and late adulthood, with adjusted HRs (95% CIs) of 0.95 (0.93-0.98) for all-cause mortality; 0.91 (0.87-0.96) for cardiovascular mortality and 0.94 (0.874-0.999) for respiratory mortality. Specifically, the association with mortality seemed to attenuate with age - stronger in middle-aged adults than in older adults. A similar association between breastfeeding in infancy and all-cause mortality was found in the meta-analysis.

CONCLUSION

Breastfeeding in infancy is associated with a lower risk of mortality - even decades later - in middle and late adulthood.

Infancy Dietary Patterns, Development, and Health: An Extensive Narrative Review

Correct dietary patterns are important for a child’s health from birth to adulthood. Understanding a child’s health as a state of entire physical, mental, and social well-being is essential. However, reaching adulthood in a complete health proper state is determined by feeding and dietary habits during preconception, pregnancy, or children infancy. Different factors, such as the mother’s lifestyle, culture, or socioeconomic status, are crucial during all these phases. In this review, we aimed to assess the long-term associations between infancy dietary patterns and health and their influence on development and growth. To reach this objective, a consensus critical review was carried out using primary sources such as scientific articles, and secondary bibliographic indexes, databases, and web pages. PubMed, SciELO, and Google Scholar were the tools used to complete this research. We found that high-income countries promote high-calorie foods and, consequently, obesity problems among children are rising. However, undernutrition is a global health issue concerning children in low- and middle-income countries; thus, parental socioeconomic status in early life is essential to children’s health and development, showing that biological, social, and environmental influences are increased risk factors for chronic diseases. This narrative review is aimed to collect evidence for early nutritional intervention and future disease prevention.

To what extent does confounding explain the association between breastfeeding duration and cognitive development up to age 14? Findings from the UK Millennium Cohort Study

Background

Breastfeeding duration is associated with improved cognitive development in children, but it is unclear whether this is a causal relationship or due to confounding. This study evaluates whether the observed association is explained by socioeconomic position (SEP) and maternal cognitive ability.

Methods

Data from 7,855 singletons born in 2000–2002 and followed up to age 14 years within the UK Millennium Cohort Study were analysed. Mothers reported breastfeeding duration, and children’s cognitive abilities were assessed at 5, 7, 11, and 14 years using validated measures. Standardised verbal (age 5 to 14) and spatial (age 5 to 11) cognitive scores were compared across breastfeeding duration groups using multivariable linear mixed-effects models (repeated outcome measures).

Results

At all ages, longer breastfeeding durations were associated with higher cognitive scores after accounting for the child’s own characteristics. Adjustment for SEP approximately halved the effect sizes. Further adjustment for maternal cognitive scores removed the remaining associations at age 5, but not at ages 7, 11 and 14 (e.g.: verbal scores, age 14; breastfed ≥12 months vs never breastfed: 0.26 SD; 95%CI: 0.18, 0.34).

Conclusion

The associations between breastfeeding duration and cognitive scores persist after adjusting for SEP and maternal cognitive ability, however the effect was modest.

Regression to the mean in latent change score models: an example involving breastfeeding and intelligence

Background

Latent change score models are often used to study change over time in observational data. However, latent change score models may be susceptible to regression to the mean. Earlier observational studies have identified a positive association between breastfeeding and child intelligence, even when adjusting for maternal intelligence.

Method

In the present study, we investigate regression to the mean in the case of breastfeeding and intelligence of children. We used latent change score modeling to analyze intergenerational change in intelligence, both from mothers to children and backward from children to mothers, in the 1979 National Longitudinal Survey of Youth (NLSY79) dataset (N = 6283).

Results

When analyzing change from mothers to children, breastfeeding was found to have a positive association with intergenerational change in intelligence, whereas when analyzing backward change from children to mothers, a negative association was found.

Conclusions

These discrepant findings highlight a hidden flexibility in the analytical space and call into question the reliability of earlier studies of breastfeeding and intelligence using observational data.

Infant Formula Supplemented With Milk Fat Globule Membrane, Long-Chain Polyunsaturated Fatty Acids, and Synbiotics Is Associated With Neurocognitive Function and Brain Structure of Healthy Children Aged 6 Years: The COGNIS Study

Background

Adequate nutrient intake during the first few months of life plays a critical role on brain structure and function development.

Objectives

To analyze the long-term effects of an experimental infant formula (EF) on neurocognitive function and brain structure in healthy children aged 6 years compared to those fed with a standard infant formula or breastfed.

Methods

The current study involved 108 healthy children aged 6 years and participating in the COGNIS Study. At 0-2 months, infants were randomized to receive up to 18 months of life a standard infant formula (SF) or EF enriched with milk fat globule membrane (MFGM), long-chain polyunsaturated fatty acids (LC-PUFAs) and synbiotics. Furthermore, a reference group of breastfed (BF) infants were also recruited. Children were assessed using neurocognitive tests and structural Magnetic Resonance Imaging (MRI) at 6 years old.

Results

Experimental infant formula (EF) children showed greater volumes in the left orbital cortex, higher vocabulary scores and IQ, and better performance in an attention task than BF children. EF children also presented greater volumes in parietal regions than SF kids. Additionally, greater cortical thickness in the insular, parietal, and temporal areas were found in children from the EF group than those fed with SF or BF groups. Further correlation analyses suggest that higher volumes and cortical thickness of different parietal and frontal regions are associated with better cognitive development in terms of language (verbal comprehension) and executive function (working memory). Finally, arachidonic acid (ARA), adrenic acid (AdA), docosahexaenoic acid (DHA) levels in cheek cell glycerophospholipids, ARA/DHA ratio, and protein, fatty acid, and mineral intake during the first 18 months of life seem to be associated with changes in the brain structures at 6 years old.

Conclusions

Supplemented infant formula with MFGM components, LC-PUFAs, and synbiotics seems to be associated to long-term effects on neurocognitive development and brain structure in children at 6 years old.

Clinical Trial Registration

https://www.clinicaltrials.gov/, identifier: NCT02094547.

Is the association between dietary patterns and cognition mediated by children's adiposity? A longitudinal approach in Generation XXI birth cohort

BACKGROUND/AIMS

There is a consistent body of evidence on the association between single nutrients and cognition, but the role of a healthful dietary pattern on cognition in children has been seldomly studied. This study aims to assess the association between dietary patterns at 4 years (y) and cognitive abilities at 10-13y and examine whether adiposity mediated these associations.

METHODS

This study used data from a sub-sample of the population-based birth cohort Generation XXI, with complete information on diet and cognition (n = 3575). At 4y, data on dietary intake was collected by a validated food frequency questionnaire and dietary patterns were derived by latent class analysis, namely Energy-dense food (EDF) pattern, Snacking pattern and Healthier pattern (Reference). At 10-13y, the Portuguese Version of the Wechsler Intelligence Scale for Children®-Third Edition was administered by trained psychologists and age-adjusted composite scores were computed: a Full-Scale Intelligence Quotient (IQ), plus a Verbal IQ, Performance IQ and Processing Speed IQ. Age- and sex-specific body mass index (BMI) z-scores, body fat percentage from bioimpedance, and waist-to-weight ratio and waist-to-hip ratio were used as measures of adiposity. Regression coefficients and 95% confidence intervals (CI) were computed using linear regression models (adjusted for maternal age and education, pre-pregnancy BMI, smoking and alcohol intake during pregnancy, child's sex, birthweight, exclusive breastfeeding duration and having siblings at 4y). Mediation analysis was conducted using path analysis.

RESULTS

After adjustment, children classified in the EDF or a Snacking patterns at 4y were more likely to have lower scores on total IQ (β = -0.116; 95%CI:-0.192,-0.039 and β = -0.148; 95%CI -0.252,-0.044, respectively), Verbal IQ (β = -0.104; 95%CI -0.177, -0.031 and β = -0.163; 95%CI -0.262,-0.064, respectively) and Performance IQ (β = -0.116 95%CI -0.193,-0.040 and β = -0.147; 95%CI -0.250,-0.042, respectively) at 10-13y, when compared to those classified in the Healthier pattern. None of the adiposity measures seemed to explain the associations between dietary patterns and IQ.

CONCLUSION

This study supports that early unhealthy dietary patterns were associated with lower child's cognitive ability, but this effect did not seem to be mediated by adiposity.

Breast feeding and infant development in a cohort with sibling pair analysis: the Japan Environment and Children's Study

OBJECTIVES

To investigate the association between breast feeding and infant development during the first year of life using sibling comparison.

DESIGN

Nationwide prospective birth cohort study with sibling pair analysis.

SETTING

15 regional centres that participated in the Japan Environment and Children's Study.

PARTICIPANTS

This study included 77 119 children (singleton, term birth and no malformation/severe diseases) whose mothers were registered between January 2011 and March 2014, including 3521 duos or trios of siblings.

PRIMARY OUTCOME MEASURES

The primary outcome was developmental delay at 6 and 12 months of age, assessed using the Japanese translation of the Ages and Stages Questionnaires, third edition. Multivariable regression analyses adjusted for confounders were performed to estimate the risk ratios of delay associated with any or exclusive breast feeding. Pairs of siblings discordant for statuses were selected, and conditional regression analyses were conducted with a matched cohort design.

RESULTS

Developmental delay was identified in 6162 (8.4%) and 10 442 (14.6%) children at 6 and 12 months of age, respectively. Any breast feeding continued until 6 months or 12 months old was associated with reduced developmental delay at 12 months of age (adjusted risk ratio (95% CI): 0.81 (0.77 to 0.85) and 0.81 (0.78 to 0.84), respectively). Furthermore, exclusive breast feeding until 3 months was associated with reduced developmental delay at 12 months of age (adjusted risk ratio, 0.86 (95% CI 0.83 to 0.90)). In sibling pair analysis, the association between any breast feeding until 12 months and reduced developmental delay at 12 months of age persisted (adjusted risk ratio, 0.64 (95% CI 0.43 to 0.93)).

CONCLUSIONS

The present study demonstrated the association of continuous breast feeding with reduced developmental delay at 1 year of age using sibling pair analysis, in which unmeasured confounding factors are still present but less included. This may provide an argument to promote breastfeeding continuation.

Analysis of Maternal Prenatal Weight and Offspring Cognition and Behavior: Results From the Promotion of Breastfeeding Intervention Trial (PROBIT) Cohort

IMPORTANCE

Prenatal experiences can influence fetal brain development.

OBJECTIVE

To examine associations of maternal prenatal body mass index (BMI) with cognition and behavior of offspring born full-term.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study examined follow-up data from a breastfeeding promotion intervention at 31 hospitals and affiliated polyclinics in the Republic of Belarus. Participants included 11 276 children who were evaluated from birth (1996-1997) to adolescence (2017-2019), with maternal BMI information available in prenatal medical records.

EXPOSURES

Maternal BMI, calculated as weight in kilograms divided by height in meters squared, after 35 weeks gestation; secondary analyses examined maternal BMI at other time points and paternal BMI.

MAIN OUTCOMES AND MEASURES

Trained pediatricians assessed child cognition with the Wechsler Abbreviated Scales of Intelligence (WASI) at 6.5 years and the computerized self-administered NeuroTrax battery at 16 years, both with an approximate mean (SD) of 100 (15). Parents and teachers rated behaviors at 6.5 years using the Strengths and Difficulties Questionnaire (SDQ, range 0-40). Mixed-effects linear regression analyses corrected for clustering, adjusted for the randomized intervention group and baseline parental sociodemographic characteristics, and were considered mediation by child BMI.

RESULTS

Among 11 276 participants, 9355 women (83%) were aged 20 to 34 years, 10 128 (89.8%) were married, and 11 050 (98.0%) did not smoke during pregnancy. Each 5-unit increase in of maternal late-pregnancy BMI (mean [SD], 27.2 [3.8]) was associated with lower offspring WASI performance intelligence quotient (IQ) (-0.52 points; 95% CI, -0.87 to -0.17 points) at 6.5 years and lower scores on 5 of 7 NeuroTrax subscales and the global cognitive score at 16 years (-0.67 points; 95% CI, -1.06 to -0.29 points). Results were similar after adjustment for sociodemographic characteristics, pregnancy complications, and paternal BMI and were not mediated by child weight. Higher late pregnancy maternal BMI was also associated with more behavioral problems reported on the SDQ by teachers but not associated with parent-reported behaviors (externalizing behaviors: 0.13 points; 95% CI, 0.02 to 0.24 points; and total difficulties: 0.14 points, 95% CI, -0.02 to 0.30 points). Results were similar for maternal BMI measured in the first trimester or postpartum. In contrast, higher 6.5-year paternal BMI was associated with slightly better child cognition (WASI verbal IQ: 0.42 points; 95% CI, 0.02 to 0.82 points; NeuroTrax executive function score: 0.68 points; 95% CI, 0.24 to 1.12 points) and fewer teacher-reported behavioral problems (total difficulties: -0.29 points; 95% CI, -0.46 to -0.11 points).

CONCLUSIONS AND RELEVANCE

This cohort study supports findings from animal experiments and human observational studies in settings with higher maternal BMI and obesity rates. Higher maternal prenatal BMI may be associated with poorer offspring brain development, although residual confounding cannot be excluded.

Influence of Early Lactation Assistance on Inpatient Exclusive Breastfeeding Rates

BACKGROUND

Human milk feeding reduces the incidence and costs of several maternal and childhood illnesses. Initiation and success of human milk feeding are influenced by race, socioeconomic status, and family support. The influence of early in-hospital lactation assistance in breastfeeding success has been not well described.

RESEARCH AIMS

We aimed to determine how suspected known factors influencing breastfeeding success influence in-hospital human milk feeding rates. Second, we aimed to examine how timing of lactation assistance is related to success of human milk feeding during the newborn hospitalization for healthy infants.

METHODS

We conducted a retrospective cohort study of term infants born between January 1, 2014 and December 31, 2016 at a large tertiary academic hospital. We considered "success" to be 100% human milk feeding during the birth hospitalization, and compared differences in success by demographics, payor, race, and initial feeding preference. Influences of lactation assistance on success were analyzed using multivariable logistic regression.

RESULTS

Mean success with exclusive human milk feeding among 7,370 infants was 48.9%, (n = 3,601). Successful participants were more likely to be 39-40 weeks' gestation (64.9%, n = 2,340), non-Hispanic/non-Latino (80.0%, n = 2,882), and using private insurance (69.2%, n = 2,491). Participants who had early feeding assisted by an International Board Certified Lactation Consultant (IBCLC) before being fed any formula were more likely to be successful than participants who had a feeding assisted by a non-IBCLC nurse (80% vs. 40% respectively).

CONCLUSIONS

Success for exclusive human milk feeding during newborn hospitalization is strongly associated with several factors. Early intervention with IBCLCs can greatly improve breastfeeding success.

Early childhood growth trajectory and later cognitive ability: evidence from a large prospective birth cohort of healthy term-born children

BACKGROUND

Most studies of associations between child growth and cognitive ability were based on size at one or two ages and a single measure of cognition. We aimed to characterize different aspects of early growth and their associations with cognitive outcomes in childhood through adolescence.

METHODS

In a sample of 12 368 Belarusian children born at term, we examined associations of length/height and weight trajectories over the first 6.5 years of life with cognitive ability at 6.5 and 16 years and its change over time. We estimated growth trajectories using two random-effects models-the SuperImposition by Translation and Rotation to model overall patterns of growth and the Jenss-Bayley to distinguish growth in infancy from post infancy. Cognitive ability was measured using the Wechsler Abbreviated Scales of Intelligence at 6.5 years and the computerized NeuroTrax test at 16 years.

RESULTS

Higher length/height between birth and 6.5 years was associated with higher cognitive scores at 6.5 and 16 years {2.7 points [95% confidence interval (CI): 2.1, 3.2] and 2.5 points [95% CI: 1.9, 3.0], respectively, per standard deviation [SD] increase}. A 1-SD delay in the childhood height-growth spurt was negatively associated with cognitive scores [-2.4 (95% CI: -3.0, -1.8) at age 6.5; -2.2 (95% CI: -2.7, -1.6) at 16 years]. Birth size and post-infancy growth velocity were positively associated with cognitive scores at both ages. Height trajectories were not associated with the change in cognitive score. Similar results were observed for weight trajectories.

CONCLUSIONS

Among term infants, the overall size, timing of the childhood growth spurt, size at birth and post-infancy growth velocity were all associated with cognitive ability at early-school age and adolescence.

The epidemiology of cognitive development

The epidemiology of cognitive development is an approach essentially based on large observational studies, which examines individual differences in cognitive abilities throughout childhood and their determinants. Although different in terms of methodology and main interests from developmental psychology, cognitive epidemiology offers complementary viewpoints on cognitive development and addresses fundamental research questions of interest to developmental psychologists. The present paper depicts the contributions of the epidemiological approach to the field of cognitive development and highlights the methodological advances that have made such contributions possible. We discuss the stability and developmental trajectories of cognitive functions, their main predictors, the complex interplay between environmental and genetic predictors, and the relationships between the different domains of cognition from birth to adulthood.

Mixed milk feeding: a systematic review and meta-analysis of its prevalence and drivers

CONTEXT

Extensive literature is available on exclusive breastfeeding and formula-feeding practices and health effects. In contrast, limited and unstructured literature exists on mixed milk feeding (MMF), here defined as the combination of breastfeeding and formula feeding during the same period in term infants > 72 hours old (inclusion criterion).

OBJECTIVE

A systematic review and meta-analysis were performed, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, on the global prevalence of MMF (primary outcome) and related drivers and practices (secondary outcomes).

DATA SOURCES

The search of MMF in generally healthy populations was conducted across 6 databases, restricted to publications from January 2000 to August 2018 in English, Spanish, French, and Mandarin.

DATA EXTRACTION

Two reviewers independently performed screenings and data extraction according to a priori inclusion and exclusion criteria.

DATA ANALYSIS

Of the 2931 abstracts identified, 151 full-text publications were included for data extraction and 96 of those were included for data synthesis (the majority of those were cross-sectional and cohort studies). The authors summarized data across 5 different categories (feeding intention prenatally, and 4 age intervals between > 72 hours and > 6-23 months) and 5 regional subgroups. The overall prevalence of MMF across different age intervals and regions varied between 23% and 32%; the highest rate was found for the age group 4-6 months (32%; 95% confidence interval, 27%-38%); regional comparisons indicated highest MMF rates in Asia (34%), North and South America (33%), and Middle East and Africa together (36%), using a random effects meta-analysis model for proportions. Some drivers and practices for MMF were identified.

CONCLUSION

MMF is a widespread feeding reality. A shared and aligned definition of MMF will help shed light on this feeding practice and evaluate its influence on the duration of total breastfeeding, as well as on infants' nutrition status, growth, development, and health status in the short and long terms. PROSPERO registration number CRD42018105337.

Association between Breastfeeding and DNA Methylation over the Life Course: Findings from the Avon Longitudinal Study of Parents and Children (ALSPAC)

Background: Breastfeeding is associated with short and long-term health benefits. Long-term effects might be mediated by epigenetic mechanisms, yet the literature on this topic is scarce. We performed the first epigenome-wide association study of infant feeding, comparing breastfed vs non-breastfed children. We measured DNA methylation in children from peripheral blood collected in childhood (age 7 years, N = 640) and adolescence (age 15–17 years, N = 709) within the Accessible Resource for Integrated Epigenomic Studies (ARIES) project, part of the larger Avon Longitudinal Study of Parents and Children (ALSPAC) cohort. Cord blood methylation (N = 702) was used as a negative control for potential pre-natal residual confounding. Results: Two differentially-methylated sites presented directionally-consistent associations with breastfeeding at ages 7 and 15–17 years, but not at birth. Twelve differentially-methylated regions in relation to breastfeeding were identified, and for three of them there was evidence of directional concordance between ages 7 and 15–17 years, but not between birth and age 7 years. Conclusions: Our findings indicate that DNA methylation in childhood and adolescence may be predicted by breastfeeding, but further studies with sufficiently large samples for replication are required to identify robust associations.

Do Human Milk Oligosaccharides Protect Against Infant Atopic Disorders and Food Allergy?

Atopic disorders (AD), often coexistent with food allergy (FA), start developing in early life and have lifelong health consequences. Breastfeeding is thought to be protective against AD and FA, but the data are controversial, and mechanisms are not well understood. Human milk oligosaccharides (HMOs) are complex carbohydrates that are abundant in human milk. These are thought to contribute to the development of the infant immune system by (i) promoting healthy microbiome, (ii) inhibiting pathogen binding to gut mucosa and (iii) modulating the immune system. Differences in microbiome composition between allergic and healthy infants have been observed, regardless of breastfeeding history. To date, limited studies have examined the preventive effects of HMOs on AD and FA in infants and current data relies on observation studies as trials of varying HMO intake through randomising individuals to breastfeeding are unethical. There is evidence for beneficial effects of breastfeeding on lowering the risks of FA, eczema and asthma but there are inconsistencies amongst studies in the duration of breastfeeding, diagnostic criteria for AD and the age at which the outcome was assessed. Furthermore, current analytical methods primarily used today only allow detection of 16-20 major HMOs while more than 100 types have been identified. More large-scale longitudinal studies are required to investigate the role of HMO composition and the impact of changes over the lactation period in preventing AD and FA later in life.

Perspective: The Role of Human Breast-Milk Extracellular Vesicles in Child Health and Disease

Human breast milk (HM) contains multiple bioactive substances determining its impact on children's health. Extracellular vesicles (EVs) are a heterogeneous group of secreted nanoparticles that are present in HM and may be partially responsible for its beneficial effects. The precise roles and content of EVs in HM remain largely unknown. To examine this, we performed a short narrative review on the literature focusing on HM EVs to contextualize the available data, followed by a scoping review of MEDLINE and Embase databases. We identified 424 nonduplicate citations with 19 original studies included. In this perspective, we summarize the evidence around HM EVs, highlight some theoretical considerations based on existing evidence, and provide an overview of some challenges associated with the complexity and heterogeneity of EV research. We consider how the existing data from HM studies conform to the minimal information for studies of EVs (MISEV) guidelines. Across the studies a variety of research methods were utilized involving both bench-based and translational methods, and a range of different EV contents were examined including RNA, proteins, and glycopeptides. We observed a variety of health outcomes in these studies, including allergy and atopy, necrotizing enterocolitis, and HIV. While some promising results have been demonstrated, the heterogeneity in outcomes of interest, methodological limitations, and relatively small number of studies in the field make comparison between studies or further translational work problematic. To date, no studies have examined normative values of HM EVs in a large, diverse population or with respect to potentially important influencing factors such as timing (hind- vs. foremilk), stage (colostrum vs. mature milk), and infant age (preterm vs. term), which makes extrapolation from bench or "basic" research impossible. Future research should focus on addressing the current inadequacies in the literature and utilize MISEV guidelines to inform study design.

Maternal Programming of Social Dominance via Milk Cytokines

Regular physical activity improves physical and mental health. Here we found that the effect of physical activity extends to the next generation. Voluntary wheel running of dams, from postpartum day 2 to weaning, increased the social dominance and reproductive success, but not the physical/metabolic health, of their otherwise sedentary offspring. The individual's own physical activity did not improve dominance status. Maternal exercise did not disrupt maternal care or the maternal and offspring microbiota. Rather, the development of dominance behavior in the offspring of running mothers could be explained by the reduction of LIF, CXCL1, and CXCL2 cytokines in breast milk. These data reveal a cytokine-mediated lactocrine pathway that responds to the mother's postpartum physical activity and programs offspring social dominance. As dominance behaviors are highly relevant to the individual's survival and reproduction, lactocrine programming could be an evolutionary mechanism by which a mother promotes the social rank of her offspring.

Maternal religion and breastfeeding intention and practice in the US Project Viva cohort

BACKGROUND

Religion has rarely been studied as a determinant of infant feeding practices. We examined whether religious affiliation is associated with formula feeding vs breastfeeding intention and practice in women from the United States Project Viva cohort.

METHODS

Between 1999 and 2002, 2128 pregnant women were recruited in the area of Boston, Massachusetts. They reported by questionnaire their religious affiliation, and their intended and practiced infant feeding mode (exclusive formula feeding vs partial vs exclusive breastfeeding) at different time points. We examined associations of religious affiliation with infant feeding intention and practice by modified Poisson regression and multinomial logistic regression adjusted for known sociodemographic confounders.

RESULTS

Of 1637 women with complete data, 52% reported being Catholic, 29% Protestant, 11% unaffiliated, 4% Jewish, and 4% other religion. Overall, 8.5% and 15.9% women intended and initiated exclusive formula feeding, respectively. Compared with unaffiliated women, Catholics were more at risk to intend to exclusively formula-feed their infant at birth (risk ratio [95% CI]: 6.4 [1.6-26.0]) and to exclusively formula-feed after delivery (2.4 [1.3-4.2]) and 3 months postpartum (1.3 [0.98-1.8]). The odds ratio for intending and practicing partial (vs exclusive) breastfeeding did not differ by religious affiliation at most examined time points. Associations of Protestant women with infant feeding exhibited estimates closer to unaffiliated than to Catholic women.

CONCLUSIONS

Catholic women are more at risk to intend and practice exclusive formula feeding than women of other religious affiliations. Our findings may help health care practitioners adapt their breastfeeding promotion to the mother's religious affiliation.

Associations between Civic Engagement and Community College Completion in a Nationally Representative Sample of Young Adults

Educational attainment is associated with voting and political trust, but less is known about whether voting and political trust are associated with subsequently higher educational attainment. In a sample of voting-age two-year college students in the National Longitudinal Study of Adolescent and Adult Health (n=1212), this study identified three markers of civic engagement in 2001 associated with greater attainment of certificates, associates degrees, and bachelor's degrees in 2008: voting, trusting the federal government, and affiliating with a political party. To minimize confounding, we used multivariate regression after exact and nearest-neighbor Mahalanobis matching within propensity score calipers on pre-college parent and adolescent socioeconomic status, demographics, educational expectations, health status, and parent civic participation. Voting in the 2000 presidential election was associated with greater likelihood of attaining a BA, or above; trusting the federal government was associated with greater likelihood of earning a certificate, associate's degree, or BA or above; and affiliating with a political party predicted greater likelihood of earning an associate's degree or BA, or above. These results suggest that two-year colleges that encourage voter registration and political activities may increase their students' engagement and educational attainment.

Association of infant and young child feeding practices with cognitive development at 10–12 years: a birth cohort in rural Western China

We aimed to comprehensively examine the association of breast-feeding, types and initial timing of complementary foods with adolescent cognitive development in low- and middle-income countries. We conducted a prospective cohort study of 745 adolescents aged 10–12 years who were born to women who participated in a randomised trial of prenatal micronutrient supplementation in rural Western China. An infant feeding index was constructed based on the current WHO recommendations. Full-scale intelligence quotient (FSIQ) was assessed and derived by the fourth edition of the Wechsler Intelligence Scale for Children. The duration of exclusive or any breast-feeding was not significantly associated with adolescent cognitive development. Participants who regularly consumed Fe-rich or Fe-fortified foods during 6–23 months of age had higher FSIQ than those who did not (adjusted mean differences 4·25; 95 % CI 1·99, 6·51). For cows’/goats’ milk and high protein-based food, the highest FSIQ was found in participants who initially consumed at 10–12 and 7–9 months, respectively. A strong dose–response relationship of the composite infant feeding index was also identified, with participants in the highest tertile of overall feeding quality having 3·03 (95 % CI 1·37, 4·70) points higher FSIQ than those in the lowest tertile. These findings suggest that appropriate infant feeding practices (breast-feeding plus timely introduction of appropriate complementary foods) were associated with significantly improved early adolescent cognitive development scores in rural China. In addition, improvement in Fe-rich or Fe-fortified foods complementary feeding may produce better adolescent cognitive development outcomes.

Psychological effects of breastfeeding on children and mothers

While the nutritional and physical health benefits of breastfeeding are well established, accumulating research demonstrates the far-reaching psychological effects of breastfeeding on children and their mothers. Here, we provide a non-exhaustive review of the empirical evidence, showing that breastfeeding impacts children's brain, cognitive, and socio-emotional development. In mothers, research is presented indicating that breastfeeding influences mood, affect, stress, and maternal care. The current review aims to provide a broad overview of existing findings on the psychological effects of breastfeeding, highlighting the important role that breastfeeding plays across several dimensions of psychological functioning. We also discuss the potential mechanisms that may underpin the observed effects, provide a constructive commentary on the limitations of the existing work, and put forth some considerations when evaluating this line of research.

Association of Breastfeeding and Air Pollution Exposure With Lung Function in Chinese Children

IMPORTANCE

Breastfeeding and exposure to ambient air pollutants have been found to be independently associated with respiratory health in children; however, previous studies have not examined the association of breastfeeding as a potential moderator of the association.

OBJECTIVE

To assess associations of breastfeeding and air pollution with lung function in children.

DESIGN, SETTING, AND PARTICIPANTS

Using a cross-sectional study design, children were recruited from 62 elementary and middle schools located in 7 Chinese cities from April 1, 2012, to October 31, 2013. Data analyses were conducted from November 1, 2018, to March 31, 2019.

EXPOSURES

Long-term concentrations of airborne particulate matter with a diameter of 1 μm or less (PM1), airborne particulate matter with a diameter of 2.5 μm or less (PM2.5), airborne particulate matter with a diameter of 10 μm or less (PM10), and nitrogen dioxide were estimated using a spatial statistical model matched to children's geocoded home addresses, and concentrations of PM10, sulfur dioxide, nitrogen dioxide, and ozone were measured by local air monitoring stations.

MAIN OUTCOMES AND MEASURES

Breastfeeding was defined as maternal report of having mainly breastfed for longer than 3 months. Lung function was measured using portable electronic spirometers. Using previously published predicted spirometric values for children in Northeast China as the reference, lung impairment was defined as forced vital capacity (FVC) less than 85%, forced expiratory volume in the first second of expiration less than 85%, peak expiratory flow less than 75%, or maximum midexpiratory flow less than 75%.

RESULTS

Participants included 6740 children (mean [SD] age, 11.6 [2.1] years; 3382 boys [50.2%]). There were 4751 children (70.5%) who were breastfed. Mean (SD) particulate matter concentrations ranged from 46.8 (6.5) μg/m3 for PM1 to 95.6 (9.8) μg/m3 for PM10. The prevalence of lung function impairment ranged from 6.8% for peak expiratory flow to 11.3% for FVC. After controlling for age, sex, and other covariates, 1-interquartile range greater concentration of pollutants was associated with higher adjusted odds ratios (AORs) for lung function impairment by FVC among children who were not breastfed compared with those who were (PM1: AOR, 2.71 [95% CI, 2.02-3.63] vs 1.20 [95% CI, 0.97-1.48]; PM2.5: AOR, 2.27 [95% CI, 1.79-2.88] vs 1.26 [95% CI, 1.04-1.51]; and PM10: AOR, 1.93 [95% CI, 1.58-2.37] vs 1.46 [95% CI, 1.23-1.73]). Younger age (<12 years) was associated with lower lung function impairment among the children who had been breastfed. In children from elementary schools, 1-interquartile range greater concentration of pollutants was associated with higher AORs for lung function impairment by FVC among children who had not been breastfed compared with those who had (PM1: AOR, 6.43 [95% CI, 3.97-10.44] vs 1.89 [95% CI, 1.28-2.80]; PM2.5: AOR, 3.83 [95% CI, 2.63-5.58] vs 1.50 [95% CI, 1.12-2.01]; and PM10: AOR, 2.61 [95% CI, 1.90-3.57] vs 1.52 [95% CI, 1.19-1.95]). Results from linear regression models also showed associations of air pollution with worse lung function among children who were not breastfed compared with their counterparts who were breastfed, especially for FVC (PM1: β, -240.46 [95% CI, -288.71 to -192.21] vs -38.21 [95% CI, -69.27 to -7.16] mL) and forced expiratory volume in the first second of expiration (PM1: β, -201.37 [95% CI, -242.08 to -160.65] vs -30.30 [95% CI, -57.66 to -2.94] mL).

CONCLUSIONS AND RELEVANCE

In this study, breastfeeding was associated with lower risk of lung function impairment among children in China exposed to air pollution, particularly among younger children.