Dynamics and Trends in Fecal Biomarkers of Gut Function in Children from 1-24 Months in the MAL-ED Study

Treatment Heterogeneity of Water, Sanitation, Hygiene, and Nutrition Interventions on Child Growth by Environmental Enteric Dysfunction and Pathogen Status for Young Children in Bangladesh

Background

Water, sanitation, hygiene (WSH), nutrition (N), and combined (N+WSH) interventions are often implemented by global health organizations, but WSH interventions may insufficiently reduce pathogen exposure, and nutrition interventions may be modified by environmental enteric dysfunction (EED), a condition of increased intestinal permeability and inflammation. This study investigated the heterogeneity of these treatments' effects based on individual pathogen and EED biomarker status with respect to child linear growth.

Methods

We applied cross-validated targeted maximum likelihood estimation and super learner ensemble machine learning to assess the conditional treatment effects in subgroups defined by biomarker and pathogen status. We analyzed treatment (N+WSH, WSH, N, or control) randomly assigned in-utero, child pathogen and EED data at 14 months of age, and child LAZ at 28 months of age. We estimated the difference in mean child length for age Z-score (LAZ) under the treatment rule and the difference in stratified treatment effect (treatment effect difference) comparing children with high versus low pathogen/biomarker status while controlling for baseline covariates.

Results

We analyzed data from 1,522 children, who had median LAZ of -1.56. We found that myeloperoxidase (N+WSH treatment effect difference 0.0007 LAZ, WSH treatment effect difference 0.1032 LAZ, N treatment effect difference 0.0037 LAZ) and Campylobacter infection (N+WSH treatment effect difference 0.0011 LAZ, WSH difference 0.0119 LAZ, N difference 0.0255 LAZ) were associated with greater effect of all interventions on growth. In other words, children with high myeloperoxidase or Campylobacter infection experienced a greater impact of the interventions on growth. We found that a treatment rule that assigned the N+WSH (LAZ difference 0.23, 95% CI (0.05, 0.41)) and WSH (LAZ difference 0.17, 95% CI (0.04, 0.30)) interventions based on EED biomarkers and pathogens increased predicted child growth compared to the randomly allocated intervention.

Conclusions

These findings indicate that EED biomarker and pathogen status, particularly Campylobacter and myeloperoxidase (a measure of gut inflammation), may be related to impact of N+WSH, WSH, and N interventions on child linear growth.

Statistical analysis plan for the LAKANA trial: a cluster-randomized, placebo-controlled, double-blinded, parallel group, three-arm clinical trial testing the effects of mass drug administration of azithromycin on mortality and other outcomes among 1-11-month-old infants in Mali

BACKGROUND

The Large-scale Assessment of the Key health-promoting Activities of two New mass drug administration regimens with Azithromycin (LAKANA) trial in Mali aims to evaluate the efficacy and safety of azithromycin (AZI) mass drug administration (MDA) to 1-11-month-old infants as well as the impact of the intervention on antimicrobial resistance (AMR) and mechanisms of action of azithromycin. To improve the transparency and quality of this clinical trial, we prepared this statistical analysis plan (SAP).

METHODS/DESIGN

LAKANA is a cluster randomized trial that aims to address the mortality and health impacts of biannual and quarterly AZI MDA. AZI is given to 1-11-month-old infants in a high-mortality setting where a seasonal malaria chemoprevention (SMC) program is in place. The participating villages are randomly assigned to placebo (control), two-dose AZI (biannual azithromycin-MDA), and four-dose AZI (quarterly azithromycin-MDA) in a 3:4:2 ratio. The primary outcome of the study is mortality among the intention-to-treat population of 1-11-month-old infants. We will evaluate relative risk reduction between the study arms using a mixed-effects Poisson model with random intercepts for villages, using log link function with person-years as an offset variable. We will model outcomes related to secondary objectives of the study using generalized linear models with considerations on clustering.

CONCLUSION

The SAP written prior to data collection completion will help avoid reporting bias and data-driven analysis for the primary and secondary aims of the trial. If there are deviations from the analysis methods described here, they will be described and justified in the publications of the trial results.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT04424511 . Registered on 11 June 2020.

Effect of a Homestead Food Production and Food Hygiene Intervention on Biomarkers of Environmental Enteric Dysfunction in Children Younger Than 24 Months in Rural Bangladesh: A Cluster-Randomized Controlled Trial

Poor sanitation and hygiene practices and inadequate diets can contribute to environmental enteric dysfunction (EED). We evaluated the impact of a combined homestead food production and food hygiene intervention on EED biomarkers in young children in rural Bangladesh. The analysis was conducted within the Food and Agricultural Approaches to Reducing Malnutrition (FAARM) cluster-randomized trial in Sylhet, Bangladesh. The FAARM trial enrolled 2,705 married women and their children younger than 3 years of age in 96 settlements (geographic clusters): 48 intervention and 48 control. The 3-year intervention (2015-2018) included training on gardening, poultry rearing, and improved nutrition practices and was supplemented by an 8-month food hygiene behavior change component, implemented from mid-2017. We analyzed data on 574 children age 0 to 24 months with multilevel linear regression. We assessed fecal myeloperoxidase (MPO), neopterin (NEO), and alpha-1-antitrypsin (AAT) as biomarkers of EED, and serum C-reactive protein (CRP) and alpha-1-acid glycoprotein (AGP) as biomarkers of systemic inflammation, using ELISA. There was no intervention effect on NEO, AAT, CRP, and AGP concentrations, but, surprisingly, MPO levels were increased in children of the intervention group (0.11 log ng/mL; 95% CI, 0.001-0.22). This increase was greater with increasing child age and among intervention households with poultry that were not kept in a shed. A combined homestead food production and food hygiene intervention did not decrease EED in children in our study setting. Small-scale poultry rearing promoted by the intervention might be a risk factor for EED.

Environmental enteric dysfunction: gut and microbiota adaptation in pregnancy and infancy

Environmental enteric dysfunction (EED) is a subclinical syndrome of intestinal inflammation, malabsorption and barrier disruption that is highly prevalent in low- and middle-income countries in which poverty, food insecurity and frequent exposure to enteric pathogens impair growth, immunity and neurodevelopment in children. In this Review, we discuss advances in our understanding of EED, intestinal adaptation and the gut microbiome over the 'first 1,000 days' of life, spanning pregnancy and early childhood. Data on maternal EED are emerging, and they mirror earlier findings of increased risks for preterm birth and fetal growth restriction in mothers with either active inflammatory bowel disease or coeliac disease. The intense metabolic demands of pregnancy and lactation drive gut adaptation, including dramatic changes in the composition, function and mother-to-child transmission of the gut microbiota. We urgently need to elucidate the mechanisms by which EED undermines these critical processes so that we can improve global strategies to prevent and reverse intergenerational cycles of undernutrition.

An Egg Intervention Improves Dietary Intakes but Does Not Fill Intake Gaps for Multiple Micronutrients among Infants in Rural Bangladesh

BACKGROUND

Eggs are nutrient-rich. Strengthening evidence of the impact of egg consumption on dietary quality can inform complementary feeding guidance.

OBJECTIVES

We aimed to assess the effect of an egg intervention on dietary intakes among infants aged 6-12 mo in rural Bangladesh.

METHODS

We conducted a cluster-randomized controlled trial allocating clusters (n = 566) to enteric pathogen control or placebo treatment, with daily provision of a protein-rich meal, isocaloric meal, egg, or control. Nutrition education was provided to all arms. Our focus here is on the egg and control arms. Infants were enrolled at 3 mo. From 6 mo, we visited households weekly to distribute eggs and measure compliance. A semistructured feeding questionnaire assessed 24-h intake at 6, 9, and 12 mo. Assessments were repeated in ∼10% of subjects 2-29 d later. Using NCI SAS macros, we estimated usual intake distributions for energy, protein, fat, and 18 micronutrients and the proportion meeting intake recommendations. We compared the outcomes between the arms using clustered bootstrapping.

RESULTS

Data were available from 757 infants (137 clusters) and 943 infants (141 clusters) in the egg and control arms, respectively. In the egg arm compared with the control arm, the mean usual intakes were higher for energy (610 compared with 602 kcal/d, 9 mo; 669 compared with 658 kcal/d, 12 mo), crude protein (2.2 compared with 1.7 g/(kg·d), 9 mo; 2.4 compared with 1.9 g/(kg·d), 12 mo), available protein (2.0 compared with 1.6 g/(kg·d), 9 mo; 2.1 compared with 1.8 g/(kg·d), 12 mo), and for 13 and 14 micronutrients at 9 and 12 mo, respectively. The proportion meeting intake recommendations for most micronutrients was higher in the egg arm but remained <50% for 15 and 13 micronutrients at 9 and 12 mo, respectively.

CONCLUSIONS

Daily egg consumption improved dietary intakes among Bangladeshi infants, but was insufficient to meet multiple micronutrient intake recommendations, demonstrating the need to be coupled with other strategies.

de Souza P, Costa H, Houpt ER, Bessong PO, Mduma ER, Lima AAM, Guerrant RL. Impact of Shigella infections and inflammation early in life on child growth and school-aged cognitive outcomes: Findings from three birth cohorts over eight years

Background

Shigella infections cause inflammation, which has been hypothesized to mediate the associations between Shigella and child development outcomes among children in low-resource settings. We aimed to assess whether early life inflammation and Shigella infections affect school-aged growth and cognitive outcomes from 6–8 years of age.

Methodology/principal findings

We conducted follow-up assessments of anthropometry, reasoning skills, and verbal fluency in 451 children at 6–8 years of age in the Brazil, Tanzania, and South Africa sites of MAL-ED, a longitudinal birth cohort study. We estimated the associations between Shigella burden and inflammation with linear growth at 2, 5, and 6–8 years of age, and with the cognitive test scores using linear regression and adjusting for potential confounding variables. We also assessed whether inflammation mediated the associations between Shigella and school-aged outcomes using a regression-based approach to mediation analysis. A high prevalence of Shigella was associated with a 0.32 (95% CI: 0.08, 0.56) z-score lower height-for-age z-score (HAZ) at 6–8 years compared to a low prevalence of Shigella. Intestinal inflammation had a smaller association with HAZ at 6–8 years. Shigella burden had small and consistently negative associations with cognitive outcomes in Brazil and Tanzania, but not South Africa, and the estimates were not statistically significant. Systemic inflammation was strongly associated with lower verbal fluency scores in Brazil (semantic fluency z-score difference: -0.57, 95% CI: -1.05, -0.10; phonemic fluency z-score difference: -0.48, 95% CI: -0.93, -0.03). There was no evidence that intestinal inflammation mediated the association between Shigella and HAZ or cognitive outcomes.

Conclusions/significance

While Shigella infections were consistently associated with long-term deficits in linear growth, the estimates of the negative associations between Shigella and cognitive outcomes were imprecise and only observed in the Brazil and Tanzania sites. Systemic inflammation was strongly associated with lower semantic and phonemic fluency scores in Brazil only, highlighting the site-specificity of effects.

Shigella infections are common among children in low-resource settings and cause inflammation, which may contribute to poor child development outcomes. We studied children from birth to 6–8 years of age in Brazil, Tanzania, and South Africa to assess whether Shigella infections and markers of inflammation in the first 2 years of life were associated with child development outcomes at school age, including height and cognitive assessment scores. Shigella infections were consistently associated with long-term deficits in linear growth. However, the associations between Shigella and cognitive outcomes were smaller, not statistically significant, and inconsistent across the three sites. There was no evidence that inflammation caused by Shigella explained the associations between Shigella and school-aged outcomes. Systemic inflammation was strongly associated with lower cognitive assessment scores in Brazil but not in the other sites, highlighting the differences in determinants of child development across settings. Quantifying the impact and understanding mechanisms for the effect of early life exposures to Shigella on long-term cognitive outcomes remains challenging.

Lack of Associations between Environmental Exposures and Environmental Enteric Dysfunction among 18-Month-Old Children in Rural Malawi

Environmental enteric dysfunction (EED) is common and contributes to linear growth faltering (stunting) and mortality among children in low-resource settings. A few studies on the environmental causes of EED have been conducted but the exact exposures that cause or predispose children to EED are context-specific and not clear. This study aimed to assess associations between selected environmental exposures and EED markers among 620 18-month-old children. This was a secondary analysis of data from Malawian children who participated in a randomized controlled trial (iLiNS-DYAD, registered at clinicaltrials.gov as NCT01239693) from birth to 18 months of age. Data on environmental exposures, including drinking water source, sanitation, exposure to animals, housing materials, season, residential area, and food insecurity were collected at enrolment. Biomarkers of EED included concentrations of calprotectin, regenerating 1B protein (REG1B), and alpha-1-antitrypsin from stool samples to assess intestinal inflammation, repair, and permeability, respectively. We performed bivariate and multivariable analyses to assess associations between environmental exposures and EED biomarkers. Adjusting for possible confounders, we did not find associations between the selected environmental exposures and the three biomarkers. These results do not provide support for our hypothesis that the studied adverse environmental exposures are associated with increased concentrations of children's EED markers in rural Malawi.

Association of Secretor Status with Enteropathy and Growth among Children in Bangladesh Aged 1-24 Months

Secretor status refers to the ability of an individual to secrete blood group antigens into body fluids and onto the different epithelial surfaces. Concurrent findings have demonstrated an association of the secretor status of children with susceptibility to a plethora of enteropathogens. We aimed to determine a possible association of secretor status of children with childhood enteropathy, an important causal factor for childhood growth failure. Participants of the Malnutrition and Enteric Disease (MAL-ED) birth cohort study from the Bangladesh site were enrolled along with their mothers. Saliva was analyzed for determining blood groups and secretor status of the children and their mothers by using an in-house ELISA. Approximately 59% of children and 65% of mothers were found to be secretor positive. Secretor-positive children were found to have a significantly positive association with alpha-1-antitrypsin (β-coefficient: 0.11, 95% CI: 0.07, 0.21, P < 0.01) and with environmental enteric dysfunction score (β-coefficient: 0.32, 95% CI: 0.29, 0.65, P = 0.05). However, despite a negative effect size, secretor-positive children did not show any statistical significance with length-for-age and weight-for-age z scores (LAZ and WAZ), respectively. Our findings indicate toward the genetic factor of secretor status of children being associated with childhood growth faltering, through increased susceptibility to distinct enteropathogens and the consequent development of enteric inflammation and enteropathy among children. However, these findings are only applicable in Bangladeshi settings and thus need to be validated in several other similar settings, to establish a possible relationship between the secretor status of children with enteropathy and resulting childhood growth failure.

Putative Biomarkers of Environmental Enteric Disease Fail to Correlate in a Cross-Sectional Study in Two Study Sites in Sub-Saharan Africa

Environmental enteric dysfunction (EED) is an elusive, inflammatory syndrome of the small intestine thought to be associated with enterocyte loss and gut leakiness and lead to stunted child growth. To date, the gold standard for diagnosis is small intestine biopsy followed by histology. Several putative biomarkers for EED have been proposed and are widely used in the field. Here, we assessed in a cross-sectional study of children aged 2–5 years for a large set of biomarkers including markers of protein exudation (duodenal and fecal alpha-1-antitrypsin (AAT)), inflammation (duodenal and fecal calprotectin, duodenal, fecal and blood immunoglobulins, blood cytokines, C-reactive protein (CRP)), gut permeability (endocab, lactulose-mannitol ratio), enterocyte mass (citrulline) and general nutritional status (branched-chain amino acids (BCAA), insulin-like growth factor) in a group of 804 children in two Sub-Saharan countries. We correlated these markers with each other and with anemia in stunted and non-stunted children. AAT and calprotectin, CRP and citrulline and citrulline and BCAA correlated with each other. Furthermore, BCAA, citrulline, ferritin, fecal calprotectin and CRP levels were correlated with hemoglobin levels. Our results show that while several of the biomarkers are associated with anemia, there is little correlation between the different biomarkers. Better biomarkers and a better definition of EED are thus urgently needed.

Association between intestinal bacterial carriage, biomarkers of environmental enteric dysfunction, and stunting in rural Malawian children

Background. Available data from murine studies suggest that intestinal bacteria may have a role in modulating growth phenotypes in the host. We investigated the prevalence of four gut bacteria known in murine models to impair growth (Bifidobacterium longum, Faecalibacterium prausnitzii, Dorea formicigenerans, and Akkermansia muciniphila), the level of fecal biomarkers of environmental enteric dysfunction (EED) and stunting in rural Malawian children. Methods. DNA and protein were extracted from fecal samples of rural Malawian children (aged 1-59 months) at a baseline cross-sectional survey in the Mangochi district of Malawi conducted within the framework of the Macrolides Oraux pour Réduire les Décès avec un Oeil sur la Résistance (MORDOR) trial. Intestinal carriage of bacteria was measured by PCR. Neopterin (NEO), myeloperoxidase (MPO), and alpha-1 antitrypsin (AAT), biomarkers of EED, were measured by an enzyme-linked immunosorbent assay (ELISA) test. Height-for-age Z (HAZ) score <-2 defined stunting. Tests of proportions and regression models were used to explore the relationship between bacterial carriage, EED, and stunting. Results. Fecal samples from 613 children were available for laboratory analyses. F. prausnitzii and D. formicigenerans were prevalent in over 70% of children while B. longum was the least prevalent. B. longum carriage in younger children was associated with elevated EED biomarkers. Two thirds of children had elevated NEO, 33% had elevated MPO, and 16% had elevated AAT. Stunting was found in 38%. No significant associations were found between EED biomarkers or intestinal bacteria carriage and stunting. Conclusion. Intestinal carriage of these four bacteria was not associated with stunting in Malawian children. Carriage was also not associated with EED, nor EED biomarker levels associated with stunting. Further factors acting in concert are necessary to impact EED, perturb growth, and alter gut bacterial carriage.

Infant Formula With a Specific Blend of Five Human Milk Oligosaccharides Drives the Gut Microbiota Development and Improves Gut Maturation Markers: A Randomized Controlled Trial

Background

Human milk oligosaccharides (HMOs) have important biological functions for a healthy development in early life.

Objective

This study aimed to investigate gut maturation effects of an infant formula containing five HMOs (2′-fucosyllactose, 2′,3-di-fucosyllactose, lacto-N-tetraose, 3′-sialyllactose, and 6′-sialyllactose).

Methods

In a multicenter study, healthy infants (7–21 days old) were randomly assigned to a standard cow’s milk-based infant formula (control group, CG); the same formula with 1.5 g/L HMOs (test group 1, TG1); or with 2.5 g/L HMOs (test group 2, TG2). A human milk-fed group (HMG) was enrolled as a reference. Fecal samples collected at baseline (n∼150/formula group; HMG n = 60), age 3 (n∼140/formula group; HMG n = 65) and 6 (n∼115/formula group; HMG n = 60) months were analyzed for microbiome (shotgun metagenomics), metabolism, and biomarkers.

Results

At both post-baseline visits, weighted UniFrac analysis indicated different microbiota compositions in the two test groups (TGs) compared to CG (P < 0.01) with coordinates closer to that of HMG. The relative abundance of Bifidobacterium longum subsp. infantis (B. infantis) was higher in TGs vs. CG (P < 0.05; except at 6 months: TG2 vs. CG P = 0.083). Bifidobacterium abundance was higher by ∼45% in TGs vs. CG at 6-month approaching HMG. At both post-baseline visits, toxigenic Clostridioides difficile abundance was 75–85% lower in TGs vs. CG (P < 0.05) and comparable with HMG. Fecal pH was significantly lower in TGs vs. CG, and the overall organic acid profile was different in TGs vs. CG, approaching HMG. At 3 months, TGs (vs. CG) had higher secretory immunoglobulin A (sIgA) and lower alpha-1-antitrypsin (P < 0.05). At 6 months, sIgA in TG2 vs. CG remained higher (P < 0.05), and calprotectin was lower in TG1 (P < 0.05) vs. CG.

Conclusion

Infant formula with a specific blend of five HMOs supports the development of the intestinal immune system and gut barrier function and shifts the gut microbiome closer to that of breastfed infants with higher bifidobacteria, particularly B. infantis, and lower toxigenic Clostridioides difficile.

Clinical Trial Registration

[https://clinicaltrials.gov/ct2/show/], identifier [NCT03722550].

Cessation of exclusive breastfeeding and seasonality, but not small intestinal bacterial overgrowth, are associated with environmental enteric dysfunction: A birth cohort study amongst infants in rural Kenya

Background

Environmental Enteric Dysfunction (EED) is a chronic intestinal inflammatory disorder of unclear aetiology prevalent amongst children in low-income settings and associated with stunting. We aimed to characterise development of EED and its putative risk factors amongst rural Kenyan infants.

Methods

In a birth cohort study in Junju, rural coastal Kenya, between August 2015 and January 2017, 100 infants were each followed for nine months. Breastfeeding status was recorded weekly and anthropometry monthly. Acute illnesses and antibiotics were captured by active and passive surveillance. Intestinal function and small intestinal bacterial overgrowth (SIBO) were assessed by monthly urinary lactulose mannitol (LM) and breath hydrogen tests. Faecal alpha-1-antitrypsin, myeloperoxidase and neopterin were measured as EED biomarkers, and microbiota composition assessed by 16S sequencing.

Findings

Twenty nine of the 88 participants (33%) that underwent length measurement at nine months of age were stunted (length-for-age Z score <-2). During the rainy season, linear growth was slower and LM ratio was higher. In multivariable models, LM ratio, myeloperoxidase and neopterin increased after cessation of continuous-since-birth exclusive breastfeeding. For LM ratio this only occurred during the rainy season. EED markers were not associated with antibiotics, acute illnesses, SIBO, or gut microbiota diversity. Microbiota diversified with age and was not strongly associated with complementary food introduction or linear growth impairment.

Interpretation

Our data suggest that intensified promotion of uninterrupted exclusive breastfeeding amongst infants under six months during the rainy season, where rainfall is seasonal, may help prevent EED. Our findings also suggest that therapeutic strategies directed towards SIBO are unlikely to impact on EED in this setting. However, further development of non-invasive diagnostic methods for SIBO is required.

Funding

This research was funded in part by the Wellcome Trust (Research Training Fellowship to RJC (103376/Z/13/Z)). EPKP was supported by the MRC/DfID Newton Fund (MR/N006259/1). JAB was supported by the MRC/DFiD/Wellcome Trust Joint Global Health Trials scheme (MR/M007367/1) and the Bill & Melinda Gates Foundation (OPP1131320). HHU was supported by the NIHR Oxford Biomedical Research Centre (IS-BRC-1215-20008).

A Randomized Controlled Trial of Dietary Rice Bran Intake on Microbiota Diversity, Enteric Dysfunction, and Fecal Secretory IgA in Malian and Nicaraguan Infants

BACKGROUND

Malnutrition and diarrhea are leading causes of death in children aged <5 y. Rice bran is a nutrient-dense prebiotic available globally.

OBJECTIVES

The objective of this secondary analysis was to evaluate the effects of daily rice bran supplementation on environmental enteric dysfunction (EED) markers, total fecal secretory IgA (sIgA), and microbiota in infants at high risk of malnutrition.

METHODS

Six-month-old Malian and Nicaraguan infants were randomly assigned to control or daily rice bran supplementation cohorts (1 to 5 g/d). Feces were collected monthly for 6 mo to evaluate fecal sIgA, markers of EED, and microbiota diversity. Statistical methods included linear mixed models, generalized mixed models, Spearman correlation, and Wilcoxon rank-sum tests.

RESULTS

Six-month-old Malian infants had significantly elevated sIgA (4.0× higher, P < 0.001), fecal myeloperoxidase (31.6× higher, P < 0.001), fecal α1-antitrypsin (1.8× higher, P = 0.006), and lower fecal neopterin (0.13× higher, P < 0.001) than the age-matched Nicaraguan infants. In the Nicaraguan rice bran cohort from 6 to 12 mo of age, there was a significant decrease in sIgA concentrations (0.4×, P < 0.05) and a correlation between sIgA and the EED marker α1-antitrypsin (0.523, P < 0.0001) at 12 mo of age. In Malian infants, daily rice bran ingestion resulted in decreased EED scores (0.71×, P = 0.02) and a stable sIgA concentration over time. The rice bran group of Malian infants also had correlation between sIgA and the EED marker neopterin (0.544, P < 0.001) at 12 mo of age and a significant (P < 0.05) increase in microbiota α-diversity at a younger age (9 mo with rice bran compared with 10 mo in control group), which supports earlier microbiota maturation.

CONCLUSIONS

These results support rice bran as a functional food ingredient targeting gut mucosa in children at high-risk of malnutrition.

Fecal biomarkers of environmental enteric dysfunction and associated factors among children aged 24-59 months in east Dembiya district, northwest Ethiopia

Background

Environmental enteric dysfunction is a subclinical intestinal disorder characterized by gut inflammation accompanied by morphological changes, such as blunted villi and crypt hyperplasia. This is a common illness in low and middle-income countries. However, environmental enteric dysfunction evidence is limited in Ethiopia. Accordingly, this study was conducted to measure fecal biomarkers of environmental enteric dysfunction and associated factors among children aged 24–59 months in rural northwest Ethiopia.

Methods

A community-based cross-sectional study was employed among 235 randomly selected children in a rural setting of the east Dembiya district. Stool samples were collected without fixative and analyzed for fecal biomarkers of environmental enteric dysfunction (Alpha-1-antitrypsin, neopterin, and myeloperoxidase) using commercial enzyme-linked immunosorbent assay kits and analyzed for intestinal parasites using wet mount and Kato-Katz techniques. Child behaviors related with exposure to enteropathogens, condition of the living environment and socio-demographic information were collected using interviewer-administered questionnaire and structure observation. We fitted multivariable linear regression model to assess the association between environmental factors and concentration of fecal biomarkers of environmental enteric dysfunction in the stool. Statistically significant associations were declared based on adjusted betas with the corresponding 95% confidence interval and p-value < 0.05.

Results

The median concentration of fecal markers of environmental enteric dysfunction was 350 μg/ml for Alpha-1-antitrypsin, 3320.2 ng/ml for myeloperoxidase, and 1562 nmol/l for neopterin. The median concentration of Alpha-1-antitrypsin among 161 (68.5%), myeloperoxidase among 168 (71.5%), and neopterin among 188 (80%) of the stool samples were above the normal values in non-tropical settings. Moreover, 100 (42.6%) of the children had high EED disease activity score (above the median score). The elevated concentrations of fecal biomarkers of gut inflammation and the high EED disease activity score were significantly associated with open defecation practice, mouthing of soil contaminated materials, Escherichia coli (E. coli)  contamination of drinking water, E. coli contamination of foods, E. coli contamination of soil, and intestinal parasites.

Conclusion

Overall, Alpha-1-antitrypsin, myeloperoxidase, and neopterin levels among the children in the studied region were highly elevated in comparison to populations in high-income countries. Moreover, the EED disease activity score in significant proportion of children was high, suggesting widespread intestinal inflammation and increased intestinal permeability. Extensive E. coli contamination of the living environment (drinking water, ready-to-eat foods, and courtyard soil), hygiene and sanitation behaviors (such as open defecation and mouthing of soil contaminated materials), and a high burden of intestinal parasites were identified as factors associated with the elevated concentration of fecal biomarkers of environmental enteric dysfunction. Parental care to children to avoid mouthing of soil contaminated materials and other risky behaviors that increase exposure enteric infections, and protecting the living environment (water, food and soil) from fecal contamination are important.

Effect of Community-Initiated Kangaroo Mother Care on Fecal Biomarkers of Gut Function in Low Birth Weight Infants in North India: A Randomized Clinical Trial

This individually randomized trial was conducted to estimate the effect of promoting community-initiated Kangaroo Mother Care (ciKMC) in low birth weight (LBW) infants on gut inflammation and permeability. Participants included 200 stable LBW infants (weighing 1,500-2,250 g) in North India enrolled between May and October 2017. The ciKMC intervention included promotion and support of continuous skin-to-skin contact and exclusive breastfeeding through home visits. The mothers in the intervention arm were supported to practice ciKMC until 28 days after birth, i.e., the neonatal period, or till the baby wriggled out of KMC position, if earlier. Infant stool specimens were collected during the first week of birth, and within 1 week after end of the neonatal period. Concentrations of fecal neopterin (nmol/L), myeloperoxidase (ng/mL), and alpha-1-antitrypsin (μg/mL) were determined using ELISA, and composite enteric enteropathy (EE) score at the end of the neonatal period was calculated by principal component analysis. We did not find any substantial difference in means between the ciKMC and control arm infants in the log-transformed values of neopterin (0.03; 95% CI -0.15 to 0.21), myeloperoxidase (0.28; 95% CI -0.05 to 0.61) and alpha-1-antitrypsin (0.02; 95% CI -0.30 to 0.34). The mean (SD) composite EE score was 13.6 (7.5) in the ciKMC and 12.4 (8.3) in the control arm infants, and the adjusted difference in means was, 0.4 (95% CI -1.8 to 2.7). Our findings suggest that the promotion of ciKMC did not affect gut inflammation and permeability in our target population of LBW infants in North India.

Risk Factors for Enterotoxigenic Bacteroides fragilis Infection and Association with Environmental Enteric Dysfunction and Linear Growth in Children: Results from the MAL-ED Study

Despite reports of enterotoxigenic Bacteroides fragilis (ETBF) isolation from asymptomatic children, no reports exist regarding the possible association of ETBF with long-term complications such as development of environmental enteric dysfunction (EED) and subsequent linear growth faltering in childhood. We aimed to establish a potential association between the burden of asymptomatic ETBF infection and EED and linear growth at 24 months of age using the data collected from 1,715 children enrolled in the multi-country birth cohort study, known as the Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health study. Using Poisson regression models, we evaluated the site-specific incidence rate and, subsequently, identified the risk factors and assessed the association between the burden of ETBF infection and EED score and linear growth at 24 months of age. The overall incidence rate of ETBF infections per 100 child-months across all study sites was 10.6%, with the highest and lowest incidence of ETBF infections being reported in Tanzania (19.6%) and Peru (3.6%), respectively. Female gender, longer duration of breastfeeding, and improved water access, sanitation, and hygiene practices, such as improved drinking water source, improved sanitation, and improved floor material in households, along with enhanced maternal education and less crowding in the households were found to be protective against incidences of ETBF infection. The burden of ETBF infections was found to have significant associations with EED and linear growth faltering at 24 months of age across all the study sites. Our findings warrant regular clinical monitoring to reduce the burden of ETBF infections and diminish the burden of enteropathy and linear growth faltering in childhood.

Pre-and post-treatment evaluation of intestinal inflammation in Giardia and Blastocystis infected children: a community-based study

Giardia intestinalis and Blastocystis hominis cause frequent infections in children in developing countries. However, the role of intestinal inflammation in their pathogenesis is still poorly understood. Faecal calprotectin (FC) level is used as an indicator of intestinal inflammation and neutrophil migration in the intestinal tract. The present study aimed to evaluate intestinal inflammation by measuring FC level among children infected with either G. intestinalis or B. hominis before and after treatment. Stool samples were collected from 282 children inhabiting a rural area in Egypt and examined microscopically for intestinal parasites. FC level was estimated in a group of children infected with G. intestinalis (n = 12) or B. hominis (n = 12) before and 3 weeks after receiving nitazoxanide (200 mg twice daily for 3 days) and compared to a control group (n = 18) of parasite-free children. Cases of mixed infection were excluded. Nitazoxanide cure rate was 83% in both infections with a remarkable reduction of infection intensity in uncured children. The difference in FC levels between infected children and controls was not statistically significant. Also, the difference between the pre- and post-treatment estimations was not statistically significant. Elevated levels were observed before treatment in three children (two infected with G. intestinalis and one with B. hominis) who displayed normal post-treatment levels. Although G. intestinalis and B. hominis infections appear to cause no remarkable intestinal inflammation, they may induce abnormally elevated FC levels in a subset of children.

Gut microbiome, enteric infections and child growth across a rural-urban gradient: protocol for the ECoMiD prospective cohort study

INTRODUCTION

The functional consequences of the bacterial gut microbiome for child health are not well understood. Characteristics of the early child gut microbiome may influence the course of enteric infections, and enteric infections may change the composition of the gut microbiome, all of which may have long-term implications for child growth and development.

METHODS AND ANALYSIS

We are conducting a community-based birth cohort study to examine interactions between gut microbiome conditions and enteric infections, and how environmental conditions affect the development of the gut microbiome. We will follow 360 newborns from 3 sites along a rural-urban gradient in northern coastal Ecuador, characterising enteric infections and gut microbial communities in the children every 3 to 6 months over their first 2 years of life. We will use longitudinal regression models to assess the correlation between environmental conditions and gut microbiome diversity and presence of specific taxa, controlling for factors that are known to be associated with the gut microbiome, such as diet. From 6 to 12 months of age, we will collect weekly stool samples to compare microbiome conditions in diarrhoea stools versus stools from healthy children prior to, during and after acute enteric infections, using principal-coordinate analysis and other multivariate statistical methods.

ETHICS AND DISSEMINATION

Ethics approvals have been obtained from Emory University and the Universidad San Francisco de Quito institutional review boards. The findings will be disseminated through conference presentations and peer-reviewed journals.

Impact of supplementation with milk-cereal mix during 6-12 months of age on growth at 12 months: a 3-arm randomized controlled trial in Delhi, India

BACKGROUND

A large proportion of infants in low- and middle-income countries are stunted. These infants are often fed complementary foods that are low-quality, primarily in terms of protein and micronutrients.

OBJECTIVES

We aimed to test 2 milk-cereal mixes supplemented with modest and high amounts of protein during 6-12 mo of age, compared with no supplementation, for their effect on length-for-age z score (LAZ) at 12 mo of age.

METHODS

Eligible infants (6 mo plus ≤29 d) were randomly assigned to either of the 2 interventions (modest- and high-protein) or a no supplement group. The milk-cereal mixes provided ∼125 kcal, 30%-45% energy from fats, and 80%-100% RDA of multiple micronutrients (MMN). The modest-protein group received 2.5 g protein [protein energy ratio (PER): 8%; 0.75 g from milk source] and the high-protein group received 5.6 g protein (PER: 18%, 1.68 g from milk source). One packet was given daily for 180 d. Counseling on continued breastfeeding and optimal infant-care practices was provided to all.

RESULTS

We enrolled 1548 infants (high-protein: n = 512; modest-protein: n = 519; and no supplement: n = 517). Compared with the no supplement group, there was an improvement in LAZ [adjusted mean difference (MD): 0.08; 95% CI: 0.01, 0.15], weight-for-age z score (MD: 0.12; 95% CI: 0.06, 0.19), weight-for-length z score (MD: 0.11; 95% CI: 0.02, 0.19), and midupper arm circumference z score (MD: 0.10; 95% CI: 0.02, 0.18) in the high-protein group at 12 mo of age. No significant differences for these anthropometric indicators were noted between the modest-protein and no supplement groups or between the high- and modest-protein groups.

CONCLUSIONS

Cereal mixes with higher amounts of milk-based protein and MMN may lead to improvement in linear growth and other anthropometric indexes in infants, compared with no supplementation.This trial was registered at ctri.nic.in as CTRI/2018/04/012932.

Term infant formula supplemented with milk-derived oligosaccharides shifts the gut microbiota closer to that of human milk-fed infants and improves intestinal immune defense: a randomized controlled trial

BACKGROUND

Bovine milk-derived oligosaccharides (MOS) containing primarily galacto-oligosaccharides with inherent concentrations of sialylated oligosaccharides can be added to infant formula to enhance the oligosaccharide profile.

OBJECTIVE

To investigate the effects of an MOS-supplemented infant formula on gut microbiota and intestinal immunity.

METHODS

In a double-blind, randomized, controlled trial, healthy term formula-fed infants aged 21-26 d either received an intact protein cow milk-based formula (control group, CG, n = 112) or the same formula containing 7.2 g MOS/L (experimental group, EG, n = 114) until the age of 6 mo. Exclusively human milk-fed infants (HFI, n = 70) from an observational study served as the reference. Fecal samples collected at baseline, and the ages of 2.5 and 4 mo were assessed for microbiota (16S ribosomal RNA-based approaches), metabolites, and biomarkers of gut health and immune response.

RESULTS

Aged 2.5 and 4 mo, redundancy analysis (P = 0.002) and average phylogenetic distance (P < 0.05) showed that the overall microbiota composition in EG was different from CG and closer to that of HFI. Similarly, EG caesarean-born infants were different from CG caesarean- or vaginally born infants and approaching HFI vaginally born infants. Relative bifidobacteria abundance was higher in EG compared with CG (P < 0.05) approaching HFI. At the age of 4 mo, counts of Clostridioides difficile and Clostridium perfringens were ∼90% (P < 0.001) and ∼65% (P < 0.01) lower in EG compared with CG, respectively. Geometric LS mean (95% CI) fecal secretory IgA in EG was twice that of CG [70 (57, 85) compared with 34 (28, 42) mg/g, P < 0.001] and closer to HFI. Fecal oral polio vaccine-specific IgA was ∼50% higher in EG compared with CG (P = 0.065). Compared with CG, EG and HFI had lower fecal calcium excretion (by ∼30%, P < 0.005) and fecal pH (P < 0.001), and higher lactate concentration (P < 0.001).

CONCLUSIONS

Infant formula with MOS shifts the gut microbiota and metabolic signature closer to that of HFI, has a strong bifidogenic effect, reduces fecal pathogens, and improves the intestinal immune response.

Fecal biomarkers of environmental enteric dysfunction and the gut microbiota of rural Malawian children: An observational study

Environmental enteric dysfunction (EED) is a subclinical condition of the gut characterized by changes in morphology and function with underlying chronic inflammatory responses. This study characterized composition and diversity of the gut microbiota in rural Malawian children with and without signs of EED. Fecal samples were collected from children aged 1-59 months. Neopterin, myeloperoxidase and alpha-1 antitrypsin concentrations were quantified by ELISA and combined to form a composite EED score using principal component analysis. DNA was extracted from fecal samples and V4-16S rRNA gene sequencing was used to characterize the gut microbiota. The concentrations of all three biomarkers decreased with increasing age, which is consistent with other studies of children living in similar low-income settings. Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria were the dominant phyla while Faecalibacterium and Bifidobacterium were the most prevalent genera. Increased alpha diversity was associated with a reduction in neopterin concentration. Microbiota composition was different between fecal samples with low and high composite EED scores; increased abundance of Succinivibrio was associated with reduced composite EED scores.

Understanding the role of the gut in undernutrition: what can technology tell us?

Gut function remains largely underinvestigated in undernutrition, despite its critical role in essential nutrient digestion, absorption and assimilation. In areas of high enteropathogen burden, alterations in gut barrier function and subsequent inflammatory effects are observable but remain poorly characterised. Environmental enteropathy (EE)-a condition that affects both gut morphology and function and is characterised by blunted villi, inflammation and increased permeability-is thought to play a role in impaired linear growth (stunting) and severe acute malnutrition. However, the lack of tools to quantitatively characterise gut functional capacity has hampered both our understanding of gut pathogenesis in undernutrition and evaluation of gut-targeted therapies to accelerate nutritional recovery. Here we survey the technology landscape for potential solutions to improve assessment of gut function, focussing on devices that could be deployed at point-of-care in low-income and middle-income countries (LMICs). We assess the potential for technological innovation to assess gut morphology, function, barrier integrity and immune response in undernutrition, and highlight the approaches that are currently most suitable for deployment and development. This article focuses on EE and undernutrition in LMICs, but many of these technologies may also become useful in monitoring of other gut pathologies.

An assessment of potential biomarkers of environment enteropathy and its association with age and microbial infections among children in Bangladesh

Interventional studies targeting environment enteropathy (EE) are impeded by the lack of appropriate, validated, non-invasive biomarkers of EE. Thus, we aimed to validate the association of potential biomarkers for EE with enteric infections and nutritional status in a longitudinal birth cohort study. We measured endotoxin core antibody (EndoCab) and soluble CD14 (sCD14) in serum, and myeloperoxidase (MPO) in feces using commercially available enzyme-linked immunosorbent assay (ELISA) kits. We found that levels of serum EndoCab and sCD14 increase with the cumulative incidence of enteric infections. We observed a significant correlation between the fecal MPO level in the children at 24 months of age with the total number of bacterial and viral infections, the total number of parasitic infections, and the total number of diarrheal episodes and diarrheal duration. We observed that the levels of serum EndoCab, sCD14, and fecal MPO at 3 months of age were significantly associated with whether children were malnourished at 18 months of age or not. Biomarkers such as fecal MPO, serum EndoCab and sCD14 in children at an early age may be useful as a measure of cumulative burden of preceding enteric infections, which are predictive of subsequent malnutrition status and may be useful non-invasive biomarkers for EE.

Effects of a combined water and sanitation intervention on biomarkers of child environmental enteric dysfunction and associations with height-for-age z-score: A matched cohort study in rural Odisha, India

Poor water, sanitation and hygiene (WaSH) conditions are hypothesized to contribute to environmental enteric dysfunction (EED), a subclinical condition that may be associated with chronic undernutrition and impaired linear growth. We evaluated the effect of a combined water and sanitation intervention on biomarkers of EED, and then assessed associations of biomarkers of EED with height-for-age z-scores (HAZ), in children under five. We conducted a sub-study within a matched cohort study of a household-level water and sanitation infrastructure intervention in rural Odisha, India, in which we had observed an effect of the intervention on HAZ. We collected stool samples (N = 471) and anthropometry data (N = 209) for children under age 5. We analyzed stool samples for three biomarkers of EED: myeloperoxidase (MPO), neopterin (NEO), and α1-anti-trypsin (AAT). We used linear mixed models to estimate associations between the intervention and each biomarker of EED and between each biomarker and HAZ. The intervention was inversely associated with AAT (-0.25 log μg/ml, p = 0.025), suggesting a protective effect on EED, but was not associated with MPO or NEO. We observed an inverse association between MPO and HAZ (-0.031 per 1000 ng/ml MPO, p = 0.0090) but no association between either NEO or AAT and HAZ. Our results contribute evidence that a transformative WaSH infrastructure intervention may reduce intestinal permeability, but not intestinal inflammation and immune activation, in young children. Our study also adds to observational evidence of associations between intestinal inflammation and nutritional status, as measured by HAZ, in young children.

Trial Registration: ClinicalTrials.gov (NCT02441699).

Intestinal dysfunction due to mucosal inflammation, known as environmental enteric dysfunction, has been hypothesized to contribute to child undernutrition in low- and middle-income countries. Poor water and sanitation conditions are thought to be an underlying cause of both environmental enteric dysfunction and child undernutrition. To examine these relationships, we conducted a sub-study within a larger matched cohort study of a household-level water and sanitation intervention in rural Odisha, India. We collected stool samples from children under age five years and analyzed them for three biomarkers of environmental enteric dysfunction: myeloperoxidase, neopterin, and α1-anti-trypsin. We also assessed the same children’s nutritional status by measuring their height and calculating their height-for-age z-score. We observed a protective effect of the water and sanitation infrastructure intervention on α1-anti-trypsin. We also observed an association between myeloperoxidase and child height-for-age z-score. Our results contribute evidence that a transformative water and sanitation infrastructure intervention may reduce environmental enteric dysfunction in young children. Our study also adds to observational evidence that intestinal inflammation may be related to chronic undernutrition in young children, though the exact nature and relative importance of that relationship remains unclear.

Effects of Water, Sanitation, Handwashing, and Nutritional Interventions on Environmental Enteric Dysfunction in Young Children: A Cluster-randomized, Controlled Trial in Rural Bangladesh

BACKGROUND

We hypothesized that drinking water, sanitation, handwashing (WSH), and nutritional interventions would improve environmental enteric dysfunction (EED), a potential contributor to stunting.

METHODS

Within a subsample of a cluster-randomized, controlled trial in rural Bangladesh, we enrolled pregnant women in 4 arms: control, WSH, child nutrition counseling plus lipid-based nutrient supplements (N), and nutrition plus WSH (N+WSH). Among the birth cohort, we measured biomarkers of gut inflammation (myeloperoxidase, neopterin), permeability (alpha-1-antitrypsin, lactulose, mannitol), and repair (regenerating gene 1β) at median ages 3, 14, and 28 months. Analysis was intention-to-treat.

RESULTS

We assessed 1512 children. At age 3 months, compared to controls, neopterin was reduced by nutrition (-0.21 log nmol/L; 95% confidence interval [CI], -.37, -.05) and N+WSH (-0.20 log nmol/L; 95% CI, -.34, -.06) interventions; similar reductions were observed at 14 months. At 3 months, all interventions reduced lactulose and mannitol (-0.60 to -0.69 log mmol/L). At 28 months, myeloperoxidase was elevated in the WSH and nutrition arms (0.23-0.27 log ng/mL) and lactulose was higher in the WSH arm (0.30 log mmol/L; 95% CI, .07, .53).

CONCLUSIONS

Reductions in permeability and inflammation at ages 3 and 14 months suggest that the interventions promoted healthy intestinal maturation; however, by 28 months, the WSH and nutrition arms showed elevated EED biomarkers. These results underscore the importance of developing a better understanding of EED pathophysiology and targeting interventions early in childhood, when they are likely to have the largest benefit to intestinal health.

CLINICAL TRIALS REGISTRATION

NCT01590095.

Enteropathogenic Escherichia coli Infection Induces Diarrhea, Intestinal Damage, Metabolic Alterations, and Increased Intestinal Permeability in a Murine Model

Enteropathogenic E. coli (EPEC) are recognized as one of the leading bacterial causes of infantile diarrhea worldwide. Weaned C57BL/6 mice pretreated with antibiotics were challenged orally with wild-type EPEC or escN mutant (lacking type 3 secretion system) to determine colonization, inflammatory responses and clinical outcomes during infection. Antibiotic disruption of intestinal microbiota enabled efficient colonization by wild-type EPEC resulting in growth impairment and diarrhea. Increase in inflammatory biomarkers, chemokines, cellular recruitment and pro-inflammatory cytokines were observed in intestinal tissues. Metabolomic changes were also observed in EPEC infected mice with changes in tricarboxylic acid (TCA) cycle intermediates, increased creatine excretion and shifts in gut microbial metabolite levels. In addition, by 7 days after infection, although weights were recovering, EPEC-infected mice had increased intestinal permeability and decreased colonic claudin-1 levels. The escN mutant colonized the mice with no weight loss or increased inflammatory biomarkers, showing the importance of the T3SS in EPEC virulence in this model. In conclusion, a murine infection model treated with antibiotics has been developed to mimic clinical outcomes seen in children with EPEC infection and to examine potential roles of selected virulence traits. This model can help in further understanding mechanisms involved in the pathogenesis of EPEC infections and potential outcomes and thus assist in the development of potential preventive or therapeutic interventions.

Optimisation, validation and field applicability of a 13C-sucrose breath test to assess intestinal function in environmental enteropathy among children in resource poor settings: study protocol for a prospective study in Bangladesh, India, Kenya, Jamaica, Peru and Zambia

INTRODUCTION

Environmental enteropathy (EE) is suspected to be a cause of growth faltering in children with sustained exposure to enteric pathogens, typically in resource-limited settings. A major hindrance to EE research is the lack of sensitive, non-invasive biomarkers. Current biomarkers measure intestinal permeability and inflammation, but not the functional capacity of the gut. Australian researchers have demonstrated proof of concept for an EE breath test based on using naturally ¹³C-enriched sucrose, derived from maize, to assay intestinal sucrase activity, a digestive enzyme that is impaired in villus blunting. Here, we describe a coordinated research project to optimise, validate and evaluate the usability of a breath test protocol based on highly enriched ¹³C-sucrose to quantify physiological dysfunction in EE in relevant target populations.

METHODS AND ANALYSIS

We use the ¹³C-sucrose breath test (¹³C-SBT) to evaluate intestinal sucrase activity in two phases. First, an optimisation and validation phase will (1) confirm that a ¹³C-SBT using highly enriched sucrose tracers reports similar information to the naturally enriched ¹³C-SBT; (2) examine the dose-response relationship of the test to an intestinal sucrase inhibitor; (3) validate the ¹³C-SBT in paediatric coeliac disease (4) validate the highly enriched ¹³C-SBT against EE defined by biopsy in adults and (5) validate the ¹³C-SBT against EE defined by the urinary lactulose:rhamnose ratio (LR) among children in Peru. Second, a cross-sectional study will be conducted in six resource-limited countries (Bangladesh, India, Jamaica, Kenya, Peru and Zambia) to test the usability of the optimised ¹³C-SBT to assess EE among 600 children aged 12-15 months old.

ETHICS AND DISSEMINATION

Ethical approval will be obtained from each participating study site. By working as a consortium, the test, if shown to be informative of EE, will demonstrate strong evidence for utility across diverse, low-income and middle-income country paediatric populations.

TRIAL REGISTRATION NUMBER

NCT04109352; Pre-results.

Early Life Experiences and Trajectories of Cognitive Development

BACKGROUND

Multiple factors constrain the trajectories of child cognitive development, but the drivers that differentiate the trajectories are unknown. We examine how multiple early life experiences differentiate patterns of cognitive development over the first 5 years of life in low-and middle-income settings.

METHODS

Cognitive development of 835 children from the Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) multisite observational cohort study was assessed at 6, 15, 24 (Bayley Scales of Infant and Toddler Development), and 60 months (Wechsler Preschool and Primary Scale of Intelligence). Markers of socioeconomic status, infection, illness, dietary intake and status, anthropometry, and maternal factors were also assessed. Trajectories of development were determined by latent class-mixed models, and factors associated with class membership were examined by discriminant analysis.

RESULTS

Five trajectory groups of cognitive development are described. The variables that best discriminated between trajectories included presence of stimulating and learning resources in the home, emotional or verbal responsivity of caregiver and the safety of the home environment (especially at 24 and 60 months), proportion of days (0-24 months) for which the child had diarrhea, acute lower respiratory infection, fever or vomiting, maternal reasoning ability, mean nutrient densities of zinc and phytate, and total energy from complementary foods (9-24 months).

CONCLUSIONS

A supporting and nurturing environment was the variable most strongly differentiating the most and least preferable trajectories of cognitive development. In addition, a higher quality diet promoted cognitive development while prolonged illness was indicative of less favorable patterns of development.

Epidemiology of Shigella infections and diarrhea in the first two years of life using culture-independent diagnostics in 8 low-resource settings

Culture-independent diagnostics have revealed a larger burden of Shigella among children in low-resource settings than previously recognized. We further characterized the epidemiology of Shigella in the first two years of life in a multisite birth cohort. We tested 41,405 diarrheal and monthly non-diarrheal stools from 1,715 children for Shigella by quantitative PCR. To assess risk factors, clinical factors related to age and culture positivity, and associations with inflammatory biomarkers, we used log-binomial regression with generalized estimating equations. The prevalence of Shigella varied from 4.9%-17.8% in non-diarrheal stools across sites, and the incidence of Shigella-attributable diarrhea was 31.8 cases (95% CI: 29.6, 34.2) per 100 child-years. The sensitivity of culture compared to qPCR was 6.6% and increased to 27.8% in Shigella-attributable dysentery. Shigella diarrhea episodes were more likely to be severe and less likely to be culture positive in younger children. Older age (RR: 1.75, 95% CI: 1.70, 1.81 per 6-month increase in age), unimproved sanitation (RR: 1.15, 95% CI: 1.03, 1.29), low maternal education (<10 years, RR: 1.14, 95% CI: 1.03, 1.26), initiating complementary foods before 3 months (RR: 1.10, 95% CI: 1.01, 1.20), and malnutrition (RR: 0.91, 95% CI: 0.88, 0.95 per unit increase in weight-for-age z-score) were risk factors for Shigella. There was a linear dose-response between Shigella quantity and myeloperoxidase concentrations. The burden of Shigella varied widely across sites, but uniformly increased through the second year of life and was associated with intestinal inflammation. Culture missed most clinically relevant cases of severe diarrhea and dysentery.

Shigella is the second leading cause of diarrhea morbidity and mortality among children in low and middle-income countries. We characterized the epidemiology of Shigella using highly sensitive diagnostic methods in 41,405 diarrheal and monthly non-diarrheal stools from the first two years of life in a multisite birth cohort. The prevalence of Shigella varied from 4.9%-17.8% across sites, and the incidence of Shigella-attributable diarrhea was 31.8 cases (95% CI: 29.6, 34.2) per 100 child-years. Shigella diarrhea episodes were more likely to be severe and less likely to be culture positive in younger children. Older age, unimproved sanitation, low maternal education, initiating complementary foods before 3 months, and malnutrition were risk factors for Shigella. There was a linear dose-response between Shigella quantity and myeloperoxidase, a marker of intestinal inflammation, which suggests a potential mechanism for the impact of Shigella on child growth. Because culture missed most clinically relevant cases of severe diarrhea and dysentery, molecular diagnostics may be important tools in upcoming Shigella vaccine trials.

Excreta biomarkers in response to different gut barrier dysfunction models and probiotic supplementation in broiler chickens

Increased intestinal permeability (IP) and inflammation are both linked with functionality of the intestinal barrier and in particular enterocytes. Currently, almost all assessment methods of the intestinal barrier function are invasive. The present study aimed to quantify selected proteins as novel biomarkers in excreta of broiler chickens to facilitate non-invasive assessment of gut barrier function using enzyme-linked immunosorbent assays (ELISA). It was further hypothesised that probiotics as feed additives may counteract gut barrier dysfunction. A 3 × 2 factorial arrangement of treatments was used with the main factors being gut barrier dysfunction models (control, rye-based diet, and dexamethasone-DEX) with and without probiotic supplementation (a three-strain Bacillus) using 72 male Ross 308 day-old chickens. Each of the 6 experimental treatments was replicated 12 times. On d 21 of age, fluorescein isothiocyanate dextran (FITC-d) uptake into serum was examined to test IP. Fresh excreta samples were collected on d 20. The biomarkers included alpha-1 antitrypsin (A1AT), intestinal fatty acid binding protein (I-FABP), lipocalin-2 (LCN2), fibronectin (FN), intestinal alkaline phosphatase (IAP), ovotransferrin (OVT) and superoxide dismutase [Cu-Zn] (SOD1). Only DEX increased (P<0.001) FITC-d passage to the blood on d 21 of age, indicating a greater IP. The excreta concentrations of A1AT, I-FABP and SOD1 were unaltered by the experimental treatments. DEX increased (P<0.05) FN concentration in excreta compared with control birds. Conversely, inclusion of rye in the diet reduced (P<0.05) FN but increased (P<0.001) OVT in excreta. Independently, DEX decreased IAP (P<0.05) in excreta compared with control and rye-fed birds. The excreta concentration of LCN2 tended (P = 0.086) to increase in birds injected by DEX. There was no demonstrable effect of probiotic addition on any of the studied parameters. Among the tested biomarkers, FN, IAP, and LCN2 revealed promise as biomarkers of intestinal barrier function quantified by ELISA kits.

Helicobacter pylori infection is associated with fecal biomarkers of environmental enteric dysfunction but not with the nutritional status of children living in Bangladesh

Background

Because Helicobacter pylori (H. pylori) infection and Environmental Enteric Dysfunction (EED) follow a similar mode of transmission, there can be a complex interplay between H. pylori infection and EED, both of which can influence childhood growth. We sought to investigate the factors associated with H. pylori infection and identify its relationship with the fecal biomarkers of EED including Myeloperoxidase (MPO), Neopterin (NEO), Calprotectin, Reg1B and Alpha-1 antitrypsin (AAT), and nutritional status of the children.

Methodology

Data from an on-going community-based nutrition intervention study was used for this analysis. Total 319 children aged between 12–18 months were evaluated at enrolment and at the end of a 90-day nutrition intervention. Multivariable linear regression with generalized estimating equations was done to examine the association of H. pylori infection with stool biomarker of EED and nutritional status of the children.

Principal findings

One-fifth of the participants had H. pylori infection at both the time points, with 13.8% overall persistence. Children living in crowded households had higher odds of being infected by H. pylori (AOR = 2.02; 95% CI = 1.02, 4.10; p-value = 0.045). At enrolment, 60%, 99%, 69% and 85% of the stool samples were elevated compared to the reference values set for MPO, NEO, AAT and Calprotectin in the non-tropical western countries. The proportions reduced to 52%, 99%, 67%, and 77% for the same biomarkers after the nutrition intervention. Infection with H. pylori had significant positive association with fecal AAT concentrations (Coefficient = 0.26; 95% CI = 0.02, 0.49; p-value = 0.03) and inverse relationship with Reg1B concentrations measured in the stool samples (Coefficient = -0.32; 95% CI = -0.59, -0.05; p-value = 0.02). However, H. pylori infection was not associated with the indicators of childhood growth.

Conclusions

The study findings affirmed that the acquisition and persistence of H. pylori infection in the early years of life may exert an adverse impact on intestinal health, induce gut inflammation and result in increased intestinal permeability.

Infection with H. pylori, a substantial public health burden in the tropical countries, follows the similar mode of transmission analogous to Environmental Enteric Dysfunction (EED). There can be a complex interplay between H. pylori infection and EED–both of which can influence childhood growth–but the definite role of H. pylori infection contributing to EED and subsequent growth failure is poorly understood. In this study, the authors present data from an ongoing community-based nutrition intervention study and investigated the factors associated with H. pylori infection and identify its relationship with fecal biomarkers of EED and indicators of the nutritional status of the children hailing from a resource-poor urban settlement. They demonstrated the acquisition and persistence of H. pylori infection during early childhood. The study results also corroborate that infection with H. pylori had significant positive association with fecal Alpha-1 antitrypsin concentrations and an inverse relationship with Reg1B concentrations measured in stool samples of the children. The findings revealed in this study may contribute to a better understanding of the role of H. pylori infection in contributing to EED as well as alteration of gut function in the early years of life.

Immune predictors of oral poliovirus vaccine immunogenicity among infants in South India

Identification of the causes of poor oral vaccine immunogenicity in low-income countries might lead to more effective vaccines. We measured mucosal and systemic immune parameters at the time of vaccination with oral poliovirus vaccine (OPV) in 292 Indian infants aged 6–11 months, including plasma cytokines, leukocyte counts, fecal biomarkers of environmental enteropathy and peripheral blood T-cell phenotype, focused on gut-homing regulatory CD4+ populations. We did not find a distinct immune phenotype associated with OPV immunogenicity, although viral pathogens were more prevalent in stool at the time of immunization among infants who failed to seroconvert (63.9% vs. 45.6%, p = 0.002). Using a machine-learning approach, we could predict seroconversion a priori using immune parameters and infection status with a median 58% accuracy (cross-validation IQR: 50–69%) compared with 50% expected by chance. Better identification of immune predictors of OPV immunogenicity is likely to require sampling of mucosal tissue and improved oral poliovirus infection models.

Campylobacter jejuni capsule types in a Peruvian birth cohort and associations with diarrhoeal disease severity

Campylobacter jejuni is a leading cause of bacterial diarrhoea worldwide. The objective of this study was to examine the association between C. jejuni capsule types and clinical signs and symptoms of diarrhoeal disease in a well-defined birth cohort in Peru. Children were enrolled in the study at birth and followed until 2 years of age as part of the Malnutrition and Enteric Infections birth cohort. Associations between capsule type and clinical outcomes were assessed using the Pearson's χ2 and the Kruskal-Wallis test statistics. A total of 318 C. jejuni samples (30% from symptomatic cases) were included in this analysis. There were 22 different C. jejuni capsule types identified with five accounting for 49.1% of all isolates. The most common capsule types among the total number of isolates were HS4 complex (n = 52, 14.8%), HS5/31 complex (n = 42, 11.9%), HS15 (n = 29, 8.2%), HS2 (n = 26, 7.4%) and HS10 (n = 24, 6.8%). These five capsule types accounted for the majority of C. jejuni infections; however, there was no significant difference in prevalence between symptomatic and asymptomatic infection (all p &gt; 0.05). The majority of isolates (n = 291, 82.7%) were predicted to express a heptose-containing capsule. The predicted presence of methyl phosphoramidate, heptose or deoxyheptose on the capsule was common.

Effects of improved water, sanitation, and hygiene and improved complementary feeding on environmental enteric dysfunction in children in rural Zimbabwe: A cluster-randomized controlled trial

Background

Environmental enteric dysfunction (EED) may be an important modifiable cause of child stunting. We described the evolution of EED biomarkers from birth to 18 months in rural Zimbabwe and tested the independent and combined effects of improved water, sanitation, and hygiene (WASH), and improved infant and young child feeding (IYCF), on EED.

Methodology and findings

The Sanitation Hygiene Infant Nutrition Efficacy (SHINE) trial was a 2x2 factorial cluster-randomised trial of improved IYCF and improved WASH on child stunting and anaemia at 18 months of age. 1169 infants born to HIV-negative mothers provided plasma and faecal specimens at 1, 3, 6, 12, and 18 months of age. We measured EED biomarkers that reflect all domains of the hypothesized pathological pathway. Markers of intestinal permeability and intestinal inflammation declined over time, while markers of microbial translocation and systemic inflammation increased between 1–18 months. Markers of intestinal damage (I-FABP) and repair (REG-1β) mirrored each other, and citrulline (a marker of intestinal epithelial mass) increased from 6 months of age, suggesting dynamic epithelial turnover and regeneration in response to enteric insults. We observed few effects of IYCF and WASH on EED after adjustment for multiple comparisons. The WASH intervention decreased plasma IGF-1 at 3 months (β:0.89, 95%CI:0.81,0.98) and plasma kynurenine at 12 months (β: 0.92, 95%CI:0.87,0.97), and increased plasma IGF-1 at 18 months (β:1.15, 95%CI:1.05,1.25), but these small WASH effects did not translate into improved growth.

Conclusions

Overall, we observed dynamic trends in EED but few effects of IYCF or WASH on biomarkers during the first 18 months after birth, suggesting that these interventions did not impact EED. Transformative WASH interventions are required to prevent or ameliorate EED in low-income settings.

Child stunting remains a global health challenge rooted in an intergenerational cycle of poor health, reduced neurodevelopment and poverty. Environmental enteric dysfunction (EED) is an acquired condition of the small intestine likely resulting from frequent faecal-oral microbial exposure, which is hypothesized to underlie stunting. We found dynamic changes in EED biomarkers between 1 and 18 months of age in a cohort of rural Zimbabwean infants, suggesting a complex developmental period of intestinal maturation, adaptation and response to environmental insults. Randomized improved infant and young child feeding, and improved water, sanitation and hygiene (WASH) interventions had no meaningful impact on EED. Greater investment in transformative WASH is needed to prevent EED in low-income countries.

Impact of early-onset persistent stunting on cognitive development at 5 years of age: Results from a multi-country cohort study

Background

Globally more than 150 million children under age 5 years were stunted in 2018, primarily in low- and middle-income countries (LMICs), and the impact of early-onset, persistent stunting has not been well explored. To explore the association between early-onset persistent stunting in children and cognitive development at 5 years of age, and to identify the factors associated with early-onset stunting.

Methods and findings

Children from the MAL-ED cohort study were followed from birth to 5 years of age in six LMICs. The Wechsler Preschool Primary Scales of Intelligence (WPPSI) was used to assess cognitive abilities (fluid reasoning) at 5 years and was adapted for each culture. Stunting was categorized as early-onset persistent (first stunted at 1–6 months and persisting at 60 months), early-onset recovered (first stunted at 1–6 months and not stunted at 60 months), late-onset persistent (first stunted at 7–24 months and persisting at 60 months), late-onset recovered (first stunted at 7–24 months and not stunted at 60 months), and never (never stunted). Mixed effects linear models were used to estimate the relationship between stunting status and cognitive development. Children with early-onset persistent stunting had significantly lower cognitive scores (-2.10 (95% CI: -3.85, -0.35)) compared with those who were never stunted. Transferrin receptor (TfR) was also negatively associated with cognitive development (-0.31 (95% CI: -0.49, -0.13)), while the HOME inventory, an index of quality of the home environment (0.46 (95% CI: 0.21, 0.72)) and socio-economic status (1.50 (95% CI: 1.03, 1.98)) were positively associated with cognitive development.

Conclusions

Early-onset persistent stunting was associated with lower cognitive development in children at 5 years of age in this cohort of children.

Dietary intake from complementary feeding is associated with intestinal barrier function and environmental enteropathy in Brazilian children from the MAL-ED cohort study

A child’s diet contains nutrients and other substances that influence intestinal health. The present study aimed to evaluate the relations between complementary feeding, intestinal barrier function and environmental enteropathy (EE) in infants. Data from 233 children were obtained from the Brazilian site of the Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development Project cohort study. Habitual dietary intake from complementary feeding was estimated using seven 24-h dietary recalls, from 9 to 15 months of age. Intestinal barrier function was assessed using the lactulose–mannitol test (L–M), and EE was determined as a composite measure using faecal biomarkers concentrations – α-1-antitrypsin, myeloperoxidase (MPO) and neopterin (NEO) at 15 months of age. The nutrient adequacies explored the associations between dietary intake and the intestinal biomarkers. Children showed adequate nutrient intakes (with the exception of fibre), impaired intestinal barrier function and intestinal inflammation. There was a negative correlation between energy adequacy and L–M (ρ = −0·19, P < 0·05) and between folate adequacy and NEO concentrations (ρ = −0·21, P < 0·01). In addition, there was a positive correlation between thiamine adequacy and MPO concentration (ρ = 0·22, P < 0·01) and between Ca adequacy and NEO concentration (ρ = 0·23; P < 0·01). Multiple linear regression models showed that energy intakes were inversely associated with intestinal barrier function (β = −0·19, P = 0·02), and fibre intake was inversely associated with the EE scores (β = −0·20, P = 0·04). Findings suggest that dietary intake from complementary feeding is associated with decreased intestinal barrier function and EE in children.

Environmental enteric dysfunction: a review of potential mechanisms, consequences and management strategies

BACKGROUND

Environmental enteric dysfunction (EED) is an acquired enteropathy of the small intestine, characterized by enteric inflammation, villus blunting and decreased crypt-to-villus ratio. EED has been associated with poor outcomes, including chronic malnutrition (stunting), wasting and reduced vaccine efficacy among children living in low-resource settings. As a result, EED may be a valuable interventional target for programs aiming to reduce childhood morbidity in low and middle-income countries.

MAIN TEXT

Several highly plausible mechanisms link the proposed pathophysiology underlying EED to adverse outcomes, but causal attribution of these pathways has proved challenging. We provide an overview of recent studies evaluating the causes and consequences of EED. These include studies of the role of subclinical enteric infection as a primary cause of EED, and efforts to understand how EED-associated systemic inflammation and malabsorption may result in long-term morbidity. Finally, we outline recently completed and upcoming clinical trials that test novel interventions to prevent or treat this highly prevalent condition.

CONCLUSIONS

Significant strides have been made in linking environmental exposure to enteric pathogens and toxins with EED, and in understanding the multifactorial mechanisms underlying this complex condition. Further insights may come from several ongoing and upcoming interventional studies trialing a variety of novel management strategies.

Penalized regression models to select biomarkers of environmental enteric dysfunction associated with linear growth acquisition in a Peruvian birth cohort

Environmental enteric dysfunction (EED) is associated with chronic undernutrition. Efforts to identify minimally invasive biomarkers of EED reveal an expanding number of candidate analytes. An analytic strategy is reported to select among candidate biomarkers and systematically express the strength of each marker’s association with linear growth in infancy and early childhood. 180 analytes were quantified in fecal, urine and plasma samples taken at 7, 15 and 24 months of age from 258 subjects in a birth cohort in Peru. Treating the subjects’ length-for-age Z-score (LAZ-score) over a 2-month lag as the outcome, penalized linear regression models with different shrinkage methods were fitted to determine the best-fitting subset. These were then included with covariates in linear regression models to obtain estimates of each biomarker’s adjusted effect on growth. Transferrin had the largest and most statistically significant adjusted effect on short-term linear growth as measured by LAZ-score–a coefficient value of 0.50 (0.24, 0.75) for each log₂ increase in plasma transferrin concentration. Other biomarkers with large effect size estimates included adiponectin, arginine, growth hormone, proline and serum amyloid P-component. The selected subset explained up to 23.0% of the variability in LAZ-score. Penalized regression modeling approaches can be used to select subsets from large panels of candidate biomarkers of EED. There is a need to systematically express the strength of association of biomarkers with linear growth or other outcomes to compare results across studies.

Childhood undernutrition is widespread throughout the world and has severe, long-lasting health impacts. Substances measured in blood, urine and stool could be used as biomarkers to identify children undergoing growth failure before these impacts occur. However, it is not yet known which of the many markers that can be identified are accurate and clinically useful predictors of poor growth in infants and children. This study used a large number of candidate biomarkers of immune activation, metabolism and hormones and applied statistical methods to narrow them down from 110 different substances, to the 36 best predictors of growth in 258 Peruvian infants. It also estimated how large the effect of each of these markers was on height two months later. The biomarker with the largest effect was transferrin, a glycoprotein that can be measured in blood samples. 15-month old children with elevated transferrin were around two thirds of a centimeter taller on average at 17 months than those with low levels. Transferrin and other proteins, glycoproteins, hormones and antibodies that this study identified, can be measured easily and affordably in standard laboratories making them feasible to be used broadly as prognostic markers as part of child health and nutrition programs in under-resourced settings.

Intestinal permeability and inflammation mediate the association between nutrient density of complementary foods and biochemical measures of micronutrient status in young children: results from the MAL-ED study

BACKGROUND

Environmental enteric dysfunction (EED) is thought to increase the risk of micronutrient deficiencies, but few studies adjust for dietary intakes and systemic inflammation.

OBJECTIVE

We tested whether EED is associated with micronutrient deficiency risk independent of diet and systemic inflammation, and whether it mediates the relation between intake and micronutrient status.

METHODS

Using data from 1283 children in the MAL-ED (Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health) birth cohort we evaluated the risk of anemia, low retinol, zinc, and ferritin, and high transferrin receptor (TfR) at 15 mo. We characterized gut inflammation and permeability by myeloperoxidase (MPO), neopterin (NEO), and α-1-antitrypsin (AAT) concentrations from asymptomatic fecal samples averaged from 9 to 15 mo, and averaged the lactulose:mannitol ratio z-score (LMZ) at 9 and 15 mo. Nutrient intakes from complementary foods were quantified monthly from 9 to 15 mo and densities were averaged for analyses. α-1-Acid glycoprotein at 15 mo characterized systemic inflammation. Relations between variables were modeled using a Bayesian network.

RESULTS

A greater risk of anemia was associated with LMZ [1.15 (95% CI: 1.01, 1.31)] and MPO [1.16 (1.01, 1.34)]. A greater risk of low ferritin was associated with AAT [1.19 (1.03, 1.37)] and NEO [1.22 (1.04, 1.44)]. A greater risk of low retinol was associated with LMZ [1.24 (1.08, 1.45)]. However, MPO was associated with a lower risk of high transferrin receptor [0.86 (0.74, 0.98)], NEO with a lower risk of low retinol [0.75 (0.62, 0.89)], and AAT with a lower risk of low plasma zinc [0.83 (0.70, 0.99)]. Greater nutrient intake densities (vitamins A and B6, calcium, protein, and zinc) were negatively associated with EED. Inverse associations between nutrient densities and micronutrient deficiency largely disappeared after adjustment for EED, suggesting that EED mediates these associations.

CONCLUSIONS

EED is independently associated with an increased risk of low ferritin, low retinol, and anemia. Greater nutrient density from complementary foods may reduce EED, and the control of micronutrient deficiencies may require control of EED.

Rice bran supplementation modulates growth, microbiota and metabolome in weaning infants: a clinical trial in Nicaragua and Mali

Rice bran supplementation provides nutrients, prebiotics and phytochemicals that enhance gut immunity, reduce enteric pathogens and diarrhea, and warrants attention for improvement of environmental enteric dysfunction (EED) in children. EED is a subclinical condition associated with stunting due to impaired nutrient absorption. This study investigated the effects of rice bran supplementation on weight for age and length for age z-scores (WAZ, LAZ), EED stool biomarkers, as well as microbiota and metabolome signatures in weaning infants from 6 to 12 months old that reside in Nicaragua and Mali. Healthy infants were randomized to a control (no intervention) or a rice bran group that received daily supplementation with increasing doses at each month (1–5 g/day). Stool microbiota were characterized using 16S rDNA amplicon sequencing. Stool metabolomes were analyzed using ultra-high-performance liquid-chromatography tandem mass-spectrometry. Statistical comparisons were completed at 6, 8, and 12 months of age. Daily consumption of rice bran was safe and feasible to support changes in LAZ from 6–8 and 8–12 months of age in Nicaragua and Mali infants when compared to control. WAZ was significantly improved only for Mali infants at 8 and 12 months. Mali and Nicaraguan infants showed major differences in the overall gut microbiota and metabolome composition and structure at baseline, and thus each country cohort demonstrated distinct microbial and metabolite profile responses to rice bran supplementation when compared to control. Rice bran is a practical dietary intervention strategy that merits development in rice-growing regions that have a high prevalence of growth stunting due to malnutrition and diarrheal diseases. Rice is grown as a staple food, and the bran is used as animal feed or wasted in many low- and middle-income countries where EED and stunting is prevalent.

Correlates of Gut Function in Children Hospitalized for Severe Acute Malnutrition, a Cross-sectional Study in Uganda

OBJECTIVE

Children with severe acute malnutrition (SAM) may have impaired intestinal function, which can result in malabsorption, diarrhoea, and poor growth. This study evaluated the gut function of children with SAM using fecal and blood biomarkers and assessed their correlates.

METHODS

A cross-sectional study, nested in a randomized trial (www.isrctn.com, ISRCTN 16454889), was conducted at Mulago hospital, Uganda among subgroups of 400 children with complicated SAM and 30 community controls. Gut function was evaluated by 5 biomarkers: plasma citrulline, fecal myeloperoxidase and fecal neopterin, bacterially derived 16S rRNA gene and internal transcribed Spacer region (ITS) specific for Candida spp. in blood.

RESULTS

Compared with controls, children with SAM had lower median plasma citrulline (5.14 vs 27.4 μmol/L, P < 0.001), higher median fecal myeloperoxidase (18083 vs 7482 ng/mL, P = 0.001), and fecal neopterin (541 vs 210 nmol/L, P < 0.001). A higher blood concentration of 16S rRNA gene copy numbers was observed among children with SAM (95 vs 28 copies/μl, P = 0.05), whereas there was no difference in the blood concentration of Candida-specific ITS fragment.Among those with SAM, plasma citrulline was lower in children with edema, diarrhoea, dermatosis, and plasma C-reactive protein (CRP) >10 mg/L. Fecal neopterin was positively correlated with symptoms of fever and cough whereas it was negatively correlated with mid-upper arm circumference (MUAC), weight-for-height z score (WHZ), edema, and dermatosis.

CONCLUSIONS

Children with complicated SAM seem to have impaired gut function characterized by reduced enterocyte mass, intestinal inflammation, and increased bacterial translocation.

Serum Adipokines, Growth Factors, and Cytokines Are Independently Associated with Stunting in Bangladeshi Children

Growth in young children is controlled through the release of several hormonal signals, which are affected by diet, infection, and other exposures. Stunting is clearly a growth disorder, yet limited evidence exists documenting the association of different growth biomarkers with child stunting. This study explored the association between different growth biomarkers and stunting in Bangladeshi children. A quasi-experimental study was conducted among 50 stunted (length-for-age Z-score (LAZ) < -2 SD) and 50 control (LAZ ≥ -2 SD) children, aged 12-18 months, residing in a Bangladeshi slum. The enrolled stunted children received an intervention package, which included food supplementation for three months, psychosocial stimulation for six months, and routine clinical care on community nutrition center at the study field site. The controls received routine clinical care only. All children were clinically screened over the study period. Length, weight, fasting blood and fecal biomarkers were measured. All biomarkers levels were similar in both groups except for oxyntomodulin at enrolment. Leptin (adjusted odds ratio, AOR: 4.0, p < 0.01), leptin-adiponectin ratio (AOR 5.07 × 10⁸, p < 0.01), insulin-like growth factor-1 (IGF-1) (AOR 1.02, p < 0.05), and gamma interferon (IFN-γ) (AOR 0.92, p < 0.05) levels were independently associated with stunting at enrolment. Serum leptin, leptin-adiponectin ratio, interleukin-6 (IL-6), IL-10, tumor necrosis factor-alpha (TNF-α), and fecal alpha-1-antitrypsin (AAT) levels increased significantly (p < 0.001), while IFN-γ levels significantly decreased among stunted children after six months of intervention. Leptin, leptin-adiponectin ratio, IGF-1, and IFN-γ are independently associated with stunting in Bangladeshi children. This trial was registered at clinicaltrials.gov as NCT02839148.

Early Life Child Micronutrient Status, Maternal Reasoning, and a Nurturing Household Environment have Persistent Influences on Child Cognitive Development at Age 5 years: Results from MAL-ED

BACKGROUND

Child cognitive development is influenced by early-life insults and protective factors. To what extent these factors have a long-term legacy on child development and hence fulfillment of cognitive potential is unknown.

OBJECTIVE

The aim of this study was to examine the relation between early-life factors (birth to 2 y) and cognitive development at 5 y.

METHODS

Observational follow-up visits were made of children at 5 y, previously enrolled in the community-based MAL-ED longitudinal cohort. The burden of enteropathogens, prevalence of illness, complementary diet intake, micronutrient status, and household and maternal factors from birth to 2 y were extensively measured and their relation with the Wechsler Preschool Primary Scales of Intelligence at 5 y was examined through use of linear regression.

RESULTS

Cognitive T-scores from 813 of 1198 (68%) children were examined and 5 variables had significant associations in multivariable models: mean child plasma transferrin receptor concentration (β: -1.81, 95% CI: -2.75, -0.86), number of years of maternal education (β: 0.27, 95% CI: 0.08, 0.45), maternal cognitive reasoning score (β: 0.09, 95% CI: 0.03, 0.15), household assets score (β: 0.64, 95% CI: 0.24, 1.04), and HOME child cleanliness factor (β: 0.60, 95% CI: 0.05, 1.15). In multivariable models, the mean rate of enteropathogen detections, burden of illness, and complementary food intakes between birth and 2 y were not significantly related to 5-y cognition.

CONCLUSIONS

A nurturing home context in terms of a healthy/clean environment and household wealth, provision of adequate micronutrients, maternal education, and cognitive reasoning have a strong and persistent influence on child cognitive development. Efforts addressing aspects of poverty around micronutrient status, nurturing caregiving, and enabling home environments are likely to have lasting positive impacts on child cognitive development.

Enteric dysfunction and other factors associated with attained size at 5 years: MAL-ED birth cohort study findings

BACKGROUND

Poor growth in early childhood has been associated with increased risk of mortality and morbidity, as well as long-term deficits in cognitive development and economic productivity.

OBJECTIVES

Data from the MAL-ED cohort study were used to identify factors in the first 2 y of life that are associated with height-for-age, weight-for-age, and body mass index z-scores (HAZ, WAZ, BMIZ) at 5 y of age.

METHODS

A total of 1017 children were followed from near birth until 5 y of age at sites in Bangladesh, Brazil, India, Nepal, Peru, South Africa, and Tanzania. Data were collected on their growth, environmental enteric dysfunction (EED), micronutrient status, enteric pathogen burden, illness prevalence, dietary intake, and various other socio-economic and environmental factors.

RESULTS

EED biomarkers were related to size at 5 y. Mean lactulose:mannitol z-scores during the first 2 y of life were negatively associated with all of the growth measures (HAZ: -0.11 [95% CI: -0.19, -0.03]; WAZ: -0.16 [95% CI: -0.26, -0.06]; BMIZ: -0.11 [95% CI: -0.23, 0.0]). Myeloperoxidase was negatively associated with weight (WAZ: -0.52 [95% CI: -0.78, -0.26] and BMIZ: -0.56 [95% CI: -0.86, -0.26]); whereas α-1-antitrypsin had a negative association with HAZ (-0.28 [95% CI: -0.52, -0.04]). Transferrin receptor was positively related to HAZ (0.18 [95% CI: 0.06, 0.30]) and WAZ (0.21 [95% CI: 0.07, 0.35]). Hemoglobin was positively related to HAZ (0.06 [95% CI: 0.00, 0.12]), and ferritin was negatively related to HAZ (-0.08 [95% CI: -0.12, -0.04]). Bacterial density in stool was negatively associated with HAZ (-0.04 [95% CI: -0.08, 0.00]), but illness symptoms did not have any effect on size at 5 y.

CONCLUSIONS

EED markers, bacterial density, and iron markers are associated with growth at 5 y of age. Interventions to reduce bacterial burden and EED may improve long-term growth in low-income settings.

Plasma Fibroblast Growth Factor 21 Is Associated with Subsequent Growth in a Cohort of Underweight Children in Bangladesh

BACKGROUND

Current nutritional intervention strategies have not proven effective in improving childhood ponderal and linear growth in underweight and stunted children. Novel markers are needed to classify children who are likely to respond to available interventions and to identify those requiring additional interventions. Fibroblast Growth Factor 21 (FGF21), an endocrine hormone that regulates metabolism and growth during periods of reduced protein intake, may be useful in this context.

OBJECTIVES

We aimed to determine the associations between plasma FGF21 concentrations and subsequent growth, and the association between change in FGF21 concentrations and concurrent growth, in children receiving nutritional supplementation.

METHODS

A total of 120 children between ages 6 and 13 mo with weight-for-age z score (WAZ) between -3 and -2 were enrolled from an urban slum in Dhaka, Bangladesh. Children received 376-kcal feeding supplements daily for 5 mo and were followed for 5 additional mo. FGF21 was measured in plasma collected at enrollment and month 5. FGF21 values that fell above the 90th percentile of baseline concentrations (1056.5 pg/mL) were considered high. Linear regression was used to examine the association between baseline FGF21 status and 5-mo change in WAZ and length-for-age z score (LAZ), and the association between 5-mo change in FGF21 and concurrent WAZ and LAZ change.

RESULTS

The median baseline FGF21 concentration was 241.4 pg/mL (IQR: 111.7, 451.3 pg/mL). On average, children with high baseline FGF21 gained 0.58 WAZ (95% CI: 0.28, 0.88) and 0.54 LAZ (95% CI: 0.23, 0.84) more during supplementation than those with low values. Change in FGF21 concentration during supplementation was negatively associated with change in WAZ (-0.48; 95% CI: -0.67, -0.29) and LAZ (-0.31; 95% CI: -0.52, -0.11).

CONCLUSIONS

FGF21 may be a useful marker of growth faltering and may allow identification of children who are more or less likely to respond to nutritional supplementation. This trial was registered at clinicaltrials.gov as NCT02441426.

Disentangling Microbial Mediators of Malnutrition: Modeling Environmental Enteric Dysfunction

Environmental enteric dysfunction (EED) (also referred to as environmental enteropathy) is a subclinical chronic intestinal disorder that is an emerging contributor to early childhood malnutrition. EED is common in resource-limited settings, and is postulated to consist of small intestinal injury, dysfunctional nutrient absorption, and chronic inflammation that results in impaired early child growth attainment. Although there is emerging interest in the hypothetical potential for chemical toxins in the environmental exposome to contribute to EED, the propensity of published data, and hence the focus of this review, implicates a critical role of environmental microbes. Early childhood malnutrition and EED are most prevalent in resource-limited settings where food is limited, and inadequate access to clean water and sanitation results in frequent gastrointestinal pathogen exposures. Even as overt diarrhea rates in these settings decline, silent enteric infections and faltering growth persist. Furthermore, beyond restricted physical growth, EED and/or enteric pathogens also associate with impaired oral vaccine responses, impaired cognitive development, and may even accelerate metabolic syndrome and its cardiovascular consequences. As these potentially costly long-term consequences of early childhood enteric infections increasingly are appreciated, novel therapeutic strategies that reverse damage resulting from nutritional deficiencies and microbial insults in the developing small intestine are needed. Given the inherent limitations in investigating how specific intestinal pathogens directly injure the small intestine in children, animal models provide an affordable and controlled opportunity to elucidate causal sequelae of specific enteric infections, to differentiate consequences of defined nutrient deprivation alone from co-incident enteropathogen insults, and to correlate the resulting gut pathologies with their functional impact during vulnerable early life windows.

Oral polio vaccine response in the MAL-ED birth cohort study: Considerations for polio eradication strategies

Background

Immunization programs have leveraged decades of research to maximize oral polio vaccine (OPV) response. Moving toward global poliovirus eradication, the WHO recommended phased OPV-to-IPV replacement on schedules in 2012. Using the MAL-ED prospective birth cohort data, we evaluated the influence of early life exposures impacting OPV immunization by measuring OPV response for serotypes 1 and 3.

Methods

Polio neutralizing antibody assays were conducted at 7 and 15 months of age for serotypes 1 and 3. Analyses were conducted on children receiving ≥3 OPV doses (n = 1449). History of vaccination, feeding patterns, physical growth, home environment, diarrhea, enteropathogen detection, and gut inflammation were examined as risk factors for non-response [Log₂(titer) < 3] and Log₂(titer) by serotype using multivariate regression.

Findings

Serotype 1 seroconversion was significantly higher than serotype 3 (96.6% vs. 89.6%, 15 months). Model results indicate serotypes 1 and 3 failure was minimized following four and six OPV doses, respectively; however, enteropathogen detection and poor socioeconomic conditions attenuated response in both serotypes. At three months of age, bacterial detection in stool reduced serotype 1 and 3 Log₂ titers by 0.34 (95% CI 0.14–0.54) and 0.53 (95% CI 0.29–0.77), respectively, and increased odds of serotype 3 failure by 3.0 (95% CI 1.6–5.8). Our socioeconomic index, consisting of Water, Assets, Maternal education, and Income (WAMI), was associated with a 0.79 (95% CI 0.15–1.43) and 1.23 (95% CI 0.34–2.12) higher serotype 1 and 3 Log₂ titer, respectively, and a 0.04 (95% CI 0.002–0.40) lower odds of serotype 3 failure. Introduction of solids, transferrin receptor, and underweight were differentially associated with serotype response. Other factors, including diarrheal frequency and breastfeeding practices, were not associated with OPV response.

Interpretation

Under real-world conditions, improved vaccination coverage and socio-environmental conditions, and reducing early life bacterial exposures are key to improving OPV response and should inform polio eradication strategies.

Nutrient intake and environmental enteric dysfunction among Nepalese children 9-24 months old-the MAL-ED birth cohort study

BACKGROUND

Nutrient deficiencies limit the growth and turnover of intestinal mucosa, but studies assessing whether specific nutrients protect against or improve environmental enteric dysfunction (EED) are scarce. We aimed to investigate associations between nutrient intake and EED assessed by lactulose:mannitol (L:M) ratio, anti-1-antitrypsin, myeloperoxidase (MPO), and neopterin (NEO) among children 9-24 months in Bhaktapur, Nepal.

METHODS

Among 231 included children, nutrient intake was assessed monthly by 24 h recalls, and 3-month usual intake was estimated using Multiple Source Method. Associations between nutrient intake and L:M ratio (measured at 15 months) were assessed using multiple linear regression, while associations between nutrient intake and fecal markers (measured quarterly) were assessed using Generalized Estimating Equations (GEE) models.

RESULTS

We found that associations between nutrient intake from complementary food and L:M ratio, alpha-1-antitrypsin (AAT), MPO and NEO were generally negative but weak. The only significant associations between nutrient intake (potassium, magnesium, phosphorous, folate, and vitamin C) and markers for intestinal inflammation were found for MPO.

CONCLUSION

Negative but weak associations between nutrient intake and markers of intestinal inflammation were found. Significant associations between several nutrients and MPO might merit further investigation.