Associations of breastfeeding with childhood autoimmunity, allergies, and overweight: The Environmental Determinants of Diabetes in the Young (TEDDY) study

It Takes a Village: Juvenile Idiopathic Arthritis and the Microbiome

Multiple risk factors for juvenile idiopathic arthritis (JIA) influence the microbiome, and various differences in the oral and fecal microbiome have been described to date in JIA. This review summarizes what is known and discusses potential implications for future research on the microbiome in JIA.

Understanding genetic variants in context

Over the last three decades, human genetics has gone from dissecting high-penetrance Mendelian diseases to discovering the vast and complex genetic etiology of common human diseases. In tackling this complexity, scientists have discovered the importance of numerous genetic processes - most notably functional regulatory elements - in the development and progression of these diseases. Simultaneously, scientists have increasingly used multiplex assays of variant effect to systematically phenotype the cellular consequences of millions of genetic variants. In this article, we argue that the context of genetic variants - at all scales, from other genetic variants and gene regulation to cell biology to organismal environment - are critical components of how we can employ genomics to interpret these variants, and ultimately treat these diseases. We describe approaches to extend existing experimental assays and computational approaches to examine and quantify the importance of this context, including through causal analytic approaches. Having a unified understanding of the molecular, physiological, and environmental processes governing the interpretation of genetic variants is sorely needed for the field, and this perspective argues for feasible approaches by which the combined interpretation of cellular, animal, and epidemiological data can yield that knowledge.

Risk of celiac disease autoimmunity is modified by interactions between CD247 and environmental exposures

Season of birth, viral infections, HLA haplogenotypes and non-HLA variants are implicated in the development of celiac disease and celiac disease autoimmunity, suggesting a combined role of genes and environmental exposures. The aim of the study was to further decipher the biological pathways conveying the season of birth effect in celiac disease autoimmunity to gain novel insights into the early pathogenesis of celiac disease. Interactions between season of birth, genetics, and early-life environmental factors on the risk of celiac autoimmunity were investigated in the multicenter TEDDY birth cohort study. Altogether 6523 genetically predisposed children were enrolled to long-term follow-up with prospective sampling and data collection at six research centers in the USA, Germany, Sweden and Finland. Celiac disease autoimmunity was defined as positive tissue transglutaminase antibodies in two consecutive serum samples. There was a significant season of birth effect on the risk of celiac autoimmunity. The effect was dependent on polymorphisms in CD247 gene encoding for CD3ζ chain of TCR-CD3 complex. In particular, children with major alleles for SNP rs864537A > G, in CD247 (AA genotype) had an excess risk of celiac autoimmunity when born March-August as compared to other months. The interaction of CD247 with season of birth on autoimmunity risk was accompanied by interactions with febrile infections between the ages of 3-6 months. Considering the important role of TCR-CD3 complex in the adaptive immune response and our findings here, CD247 variants and their possible effect of subgroups in autoimmunity development could be of interest in the design of future gene-environment studies of celiac disease. ClinicalTrials.gov Identifier: NCT00279318.

Association between breastfeeding duration and BMI, 2009-2018: a population-based study

Background

In the 21st century, childhood overweight and obesity have become major public health issues worldwide. Previous studies have shown that breastfeeding helps prevent overweight or obesity in children. Despite the significant advantages of breastfeeding, the global exclusive breastfeeding rate for infants under 6 months old is only 40%, while in the United States, the rate is only 25%. The aim of this study is to explore the relationship between breastfeeding duration and BMI in children aged 2 to 6 in the United States, and to raise awareness of breastfeeding.

Methods

A cross-sectional study included 2,769 participants between the ages of 2 and 6 from a sample that represented the entire NHANES 2009-2018. Data was analyzed using EmpowerStats, (www.empowerstats.com) linear regression as well as Chi-square test, t-tests, multivariate regression analysis and smooth cure fitting were done.

Results

Breastfeeding duration long-term group exhibited a statistically significant negative association with BMI, with a regression coefficient of -0.21 (P < 0.05). The continuous analysis of breastfeeding duration by tertile also demonstrate a statistically significant negative association with BMI. Subgroup analysis revealed that the potential benefits of breastfeeding on BMI were more obvious in low-income environments and maternal age 18 to 35 years, with a regression coefficient of -0.57 and -0.24, respectively (all P < 0.05).

Conclusion

The findings emphasize the importance of breastfeeding in reducing childhood overweight/obesity and preventing associated diseases, both in clinical and public health settings.

Role of breastfeeding in disease prevention

Human milk provides the infant with many bioactive factors, including immunomodulating components, antimicrobials and prebiotics, which modulate the infant microbiome and immune system maturation. As a result, breastfeeding can impact infant health from infancy, through adolescence, and into adulthood. From protecting the infant from infections, to reducing the risk of obesity, type 1 diabetes and childhood leukaemia, many positive health outcomes are observed in infants receiving breastmilk. For the mother, breastfeeding protects against postpartum bleeding and depression, increases weight loss, and long-term lowers the risk of type 2 diabetes, breast and ovarian cancer, and cardiovascular diseases. Beyond infants and mothers, the wider society is also impacted because of avoidable costs relating to morbidity and mortality derived from a lack of human milk exposure. In this review, Medline was used to search for relevant articles to discuss the health benefits of breastfeeding and its societal impact before exploring future recommendations to enhance our understanding of the mechanisms behind breastfeeding's positive effects and promote breastfeeding on a global scale.

Complementary Feeding: Tradition, Innovation and Pitfalls

According to WHO, "complementary feeding (CF) is the process starting when breast milk alone or infant formula alone is no longer sufficient to meet the nutritional requirements of infants, and therefore, other foods and liquids are needed, along with breast human milk or a breastmilk substitute". CF is one of the most important "critical and sensitive periods" in human life: indeed, timing and approaches to solid foods introduction in an infant's nutrition are of utmost importance as potential epigenetic factors from infancy to adulthood. CF is also deeply influenced by each country and single-family traditions, culture, and beliefs. The aim of our narrative review is to analyze traditional CF practices, including innovative and alternative ones that emerged in the last decades, such as baby-led weaning or plant-based weaning, and to evaluate their effects on the risk of developing non-communicable diseases. Moreover, we will discuss pitfalls and misunderstandings that pediatricians frequently have to face when dealing with complementary feeding. Health care professionals must not have prejudices against parents' wishes or traditions about CF; rather, they should support and educate them in case of any alternative CF choice, always pursuing the infant's adequate growth, neuro- and taste development, and the achievement of correct eating behavior as the primary goal.

Lessons and Gaps in the Prediction and Prevention of Type 1 Diabetes

Type 1 diabetes (T1D) is a serious chronic autoimmune condition. Even though the root cause of T1D development has yet to be determined, enough is known about the natural history of T1D pathogenesis to allow study of interventions that may delay or even prevent the onset of hyperglycemia and clinical T1D. Primary prevention aims to prevent the onset of beta cell autoimmunity in asymptomatic people at high genetic risk for T1D. Secondary prevention strategies aim to preserve functional beta cells once autoimmunity is present, and tertiary prevention aims to initiate and extend partial remission of beta cell destruction after the clinical onset of T1D. The approval of teplizumab in the United States to delay the onset of clinical T1D marks an impressive milestone in diabetes care. This treatment opens the door to a paradigm shift in T1D care. People with T1D risk need to be identified early by measuring T1D related islet autoantibodies. Identifying people with T1D before they have symptoms will facilitate better understanding of pre-symptomatic T1D progression and T1D prevention strategies that may be effective.

Dietary Intake and Body Mass Index Influence the Risk of Islet Autoimmunity in Genetically At-Risk Children: A Mediation Analysis Using the TEDDY Cohort

Background/Objective

Growth and obesity have been associated with increased risk of islet autoimmunity (IA) and progression to type 1 diabetes. We aimed to estimate the effect of energy-yielding macronutrient intake on the development of IA through BMI.

Research Design and Methods

Genetically at-risk children (n = 5,084) in Finland, Germany, Sweden, and the USA, who were autoantibody negative at 2 years of age, were followed to the age of 8 years, with anthropometric measurements and 3-day food records collected biannually. Of these, 495 (9.7%) children developed IA. Mediation analysis for time-varying covariates (BMI z-score) and exposure (energy intake) was conducted. Cox proportional hazard method was used in sensitivity analysis.

Results

We found an indirect effect of total energy intake (estimates: indirect effect 0.13 [0.05, 0.21]) and energy from protein (estimates: indirect effect 0.06 [0.02, 0.11]), fat (estimates: indirect effect 0.03 [0.01, 0.05]), and carbohydrates (estimates: indirect effect 0.02 [0.00, 0.04]) (kcal/day) on the development of IA. A direct effect was found for protein, expressed both as kcal/day (estimates: direct effect 1.09 [0.35, 1.56]) and energy percentage (estimates: direct effect 72.8 [3.0, 98.0]) and the development of GAD autoantibodies (GADA). In the sensitivity analysis, energy from protein (kcal/day) was associated with increased risk for GADA, hazard ratio 1.24 (95% CI: 1.09, 1.53), p = 0.042.

Conclusions

This study confirms that higher total energy intake is associated with higher BMI, which leads to higher risk of the development of IA. A diet with larger proportion of energy from protein has a direct effect on the development of GADA.

Systematic review: early feeding practices and the risk of coeliac disease. A 2022 update and revision

BACKGROUND

The effects of early feeding practices on the risk of coeliac disease (CD) remain debated.

AIMS

To update evidence on these practices on the risk of CD and/or CD-related autoimmunity (CDA), defined as anti-transglutaminase or anti-endomysial antibody positivity METHODS: We searched MEDLINE, EMBASE and the Cochrane Library to May 2022 for randomised controlled trials (RCTs) and observational studies.

RESULTS

We included 36 publications (30 studies). In the population at genetic risk of developing CD (HLA DQ2/DQ8-positive), exclusive or any breastfeeding and longer breastfeeding duration did not reduce the risk of developing CD/CDA during childhood. While a meta-analysis of four case-control studies showed a decreased risk for CD when gluten was introduced during breastfeeding, this was not shown in RCTs and cohort studies. Age at gluten introduction was not associated with cumulative CD/CDA risk, although two RCTs suggested that earlier gluten introduction was associated with earlier CDA appearance. Evidence from six observational studies suggests that consumption of a higher amount of gluten at weaning and/or thereafter may increase CD risk. There is insufficient evidence to determine the amount of gluten associated with an increased CD/CDA risk. Regarding whether infant feeding practices modulate the risk conferred by different HLA genotypes results were inconsistent.

CONCLUSIONS

For the population at genetic risk of CD, breastfeeding and age at gluten introduction have no effect on its cumulative incidence during childhood. There is some evidence for an effect of the amount of gluten consumed at weaning and/or thereafter on CD/CDA risk.

Systematic review and meta-analysis of breastfeeding and later overweight or obesity expands on previous study for World Health Organization

AIM

To update a systematic review and meta-analysis of the association of breastfeeding with overweight or obesity that had been commissioned by the World Health Organization. We also assessed the likelihood of residual confounding.

METHODS

Two independent reviewers searched MEDLINE, LILACS and Web of Science for manuscripts published between August 2014 and May 2021. Studies that only evaluated infants were excluded. Random-effects models were used to pool the estimates.

RESULTS

The review comprised 159 studies with 169 estimates on the association of breastfeeding with overweight or obesity, and most of the studies were carried out among individuals aged 1-9 years (n = 130). Breastfeeding protected against overweight or obesity (pooled odds ratio:0.73, 95% confidence interval:0.71; 0.76). And, even among the 19 studies that were less susceptible to publication bias, residual confounding and misclassification, a benefit was observed (pooled odds ratio:0.85, 95% confidence interval:0.77; 0.93). Among those studies that were clearly susceptible to positive confounding by socioeconomic status, a benefit of breastfeeding was observed even after adjusting for socioeconomic status (pooled odds ratio:0.76, 95% confidence interval: 0.69; 0.83).

CONCLUSION

Breastfeeding reduced the odds of overweight or obesity, and this association was unlikely to be due to publication bias and residual confounding.

The Effect of Weaning with Adult Food Typical of the Mediterranean Diet on Taste Development and Eating Habits of Children: A Randomized Trial

Mediterranean Diet (Med Diet) is one of the healthiest dietary patterns. We aimed to verify the effects of weaning (i.e., the introduction of solid foods in infants previously fed only with milk) using adult foods typical of Med Diet on children eating habits, and on the microbiota composition. A randomized controlled clinical trial on 394 healthy infants randomized in a 1:1 ratio in a Med Diet group weaned with fresh; seasonal and tasty foods of Med Diet and control group predominantly weaned with industrial baby foods. The primary end point was the percentage of children showing a good adherence to Med Diet at 36 months. Secondary end points were mother’s changes in adherence to Med Diet and differences in children gut microbiota. At 36 months, children showing a good adherence to Med Diet were 59.3% in the Med Diet group and 34.3% in the control group (p < 0.001). An increase in adherence to the Med Diet was observed in the mothers of the Med Diet group children (p < 0.001). At 4 years of age children in the Med Diet group had a higher gut microbial diversity and a higher abundance of beneficial taxa. A Mediterranean weaning with adult food may become a strategy for early nutritional education, to develop a healthy microbiota, to prevent inflammatory chronic diseases and to ameliorate eating habits in children and their families.

Effect of an infant formula containing sn-2 palmitate on fecal microbiota and metabolome profiles of healthy term infants: a randomized, double-blind, parallel, controlled study

Different infant diets have strong effects on child development and may engender variations in fecal microbiota and metabolites. The objective of this study was to evaluate the effect of an infant formula containing sn-2 palmitate on fecal microbiota and metabolites in healthy term infants. The study involved three groups as indicated below. Investigational: the group fed a formula containing high sn-2 palmitate for 16 weeks. Control: the group fed a formula using a regular vegetable oil for 16 weeks. Breastfed: the group fed breast milk for 16 weeks. Fecal samples were collected at 8 weeks (n = 35, 37, and 35, respectively) and 16 weeks (n = 30, 32, and 30, respectively) for the control, investigational, and breastfed infants. Microbiota data were obtained using 16S rRNA sequencing. Short-chain fatty acid (SCFA) analysis was performed using GC-MS, and untargeted metabolomics was conducted using LC-MS. The effect of the formula containing sn-2 palmitate was different from that of the control formula on microbiota and metabolites. Sn-2 palmitate promoted the proliferation of Bifidobacterium and reduced the abundance of Escherichia-Shigella at 8 weeks. Furthermore, it increased α-diversity and enhanced acetate content in feces at both 8 and 16 weeks. In the investigational group infants, the abundance of DL-tryptophan, indole-3-acrylic acid, acetyl-β-methylcholine, L-methionine, and 2-hydroxyvaleric acid significantly increased at 8 weeks, while a notable increase in the abundance of 3-phenyllactic acid, palmitic acid, L-phenylalanine, and leucylproline was observed at 16 weeks. In addition, compared with that of the control infants, the intestinal microbiota and metabolites of sn-2 palmitate-supplemented infants were more similar to those of the breastfed infants. The study hopes to provide a scientific basis for the development of functional infant formulas in the future.

Prolonged breastfeeding and protective effects against the development of allergic rhinitis: a systematic review and meta-analysis

BACKGROUND

There is insufficient evidence to confirm the protective effects of prolonged breastfeeding against the development of allergic rhinitis (AR).

METHODOLOGY

A systematic review and meta-analysis was performed to assess the associations between prolonged breastfeeding and AR symptoms later in life. Comparisons were conducted between breastfeeding durations less than 6 months and 6 months or more and between less than 12 months and 12 months or more. Exclusive breastfeeding and nonexclusive breastfeeding were analysed separately. Outcomes were risks of AR development later in life.

RESULTS

Twenty-three observational studies (161,611 children, age 2-18 years, 51.50% male) were included. Two studies (9%) were with high quality. Both exclusive and nonexclusive prolonged breastfeeding (6 months or more) decreased the risk of AR. The long-term (12 months or more) nonexclusive breastfeeding lowered the likelihood of AR compared to the 12 months or fewer. The long-term exclusive breastfeeding did not show the same protective effect; however, this result was restricted to only one study.

CONCLUSIONS

Exclusive breastfeeding and nonexclusive breastfeeding for 6 months or more may have protective effects against the development of AR up to 18 years of age. The findings should be interpreted with caution given the limitation of low-quality observational studies.

Environmental Determinants of Type 1 Diabetes: From Association to Proving Causality

The rising incidence of type 1 diabetes (T1D) cannot be ascribed to genetics alone, and causative environmental triggers and drivers must also be contributing. The prospective TEDDY study has provided the greatest contributions in modern time, by addressing misconceptions and refining the search strategy for the future. This review outlines the evidence to date to support the pathways from association to causality, across all stages of T1D (seroconversion to beta cell failure). We focus on infections and vaccinations; infant growth and childhood obesity; the gut microbiome and the lifestyle factors which cultivate it. Of these, the environmental determinants which have the most supporting evidence are enterovirus infection, rapid weight gain in early life, and the microbiome. We provide an infographic illustrating the key environmental determinants in T1D and their likelihood of effect. The next steps are to investigate these environmental triggers, ideally though gold-standard randomised controlled trials and further prospective studies, to help explore public health prevention strategies.