Comparison of two forms of daily preventive zinc supplementation versus therapeutic zinc supplementation for diarrhea on young children's physical growth and risk of infection: study design and rationale for a randomized controlled trial

Community-Based Child Food Interventions/Supplements for the Prevention of Wasting in Children Up to 5 Years at Risk of Wasting and Nutritional Oedema: A Systematic Review and Meta-Analysis

CONTEXT

Malnutrition poses a significant threat to child health, with millions of children worldwide affected by wasting, which increases the risk of morbidity and mortality.

OBJECTIVE

In this study we sought to evaluate the effectiveness of community-based infant/child food interventions and supplements for preventing wasting among children up to 5 years at risk of wasting and nutritional oedema. The World Health Organization commissioned this review to update their guidelines on wasting due to malnutrition in children.

DATA SOURCES

Nine databases were searched from inception until July 2021 and an updated search was carried out on MEDLINE and Ovid MEDLINE until April 13, 2023, and included 24 studies (98 articles) evaluating the impact of community-based infant/child food interventions/supplements for the prevention of wasting among children up to 5 years.

DATA EXTRACTION

Two review authors independently extracted data and assessed the quality of included studies using the Cochrane Risk of Bias Tool 2.0. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria were used to assess the quality of evidence.

DATA ANALYSIS

This review included 19 cluster-randomized controlled trials (cRCTs) and 5 RCTs evaluating the impact of community-based infant/child food interventions/supplements including fortified blended foods (FBFs), small-quantity (SQ), medium-quantity (MQ), or large-quantity (LQ) lipid-based nutrient supplements (LNS), and multiple micronutrient powder (MNP) for the prevention of wasting among children up to 5 years of age. The analysis showed that infants/children given supplementation with LNS (either SQ, MQ, or LQ) had significantly reduced wasting and significant improvements in weight-for-age z-score, mid-upper-arm circumference (MUAC), and underweight prevalence, along with significant reductions in mortality. The MNP supplementation had little or no impact on wasting but was associated with increased incidences of rapid breathing/chest indrawing and diarrhea morbidity. Overall, the studies were judged to have raised some concerns for the outcomes of wasting and adverse anthropometric indices. However, the GRADE analysis suggested low-to-moderate certainty of outcomes.

CONCLUSIONS

The findings of this review highlight the effectiveness of SQ-LNS and MQ/LQ-LNS supplementation in decreasing rates of wasting, underweight, and mortality and increasing MUAC and weight-for-age z-scores. Methodological limitations in most studies emphasize the need for future trials with direct comparisons of various dietary supplementation strategies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42021277429.

Insulin-like Growth Factor 1 (IGF1), IGF Binding Protein-3 (IGFBP3) and Growth Response to Daily Zinc Supplementation: A Randomized Trial in Rural Laotian Children

OBJECTIVES

To assess (a) the impact of daily preventive zinc tablets (7 mg; PZ), zinc-containing multiple micronutrient powder (10 mg zinc, and 13 other micronutrients; MNP) or placebo, delivered for 9 months, on Insulin-like Growth Factor 1 (IGF1) and IGF Binding Protein 3 (IGFBP3) among Laotian children 6-23 months, and (b) whether the effects of PZ and MNP on length-for-age z-scores (LAZ) and weight-for-age z-scores (WAZ) are modified by baseline IGF1 and IGFBP3.

DESIGN

A double-blind, placebo-controlled trial (N = 419).

METHODS

Plasma IGF1 and IGFBP3 concentrations at baseline and 36 weeks were analyzed by automated chemiluminescent assay. Anthropometry was assessed at baseline, at 18 and 36 weeks. Intervention effects were estimated using ANCOVA.

RESULTS

At 36 weeks, geometric mean IGF1 (~39.0-39.2 ng/mL; p = 0.99) and IGFBP3 (2038-2076 ng/mL; p = 0.83) did not differ by group. At 18 weeks (but not at 36 weeks), LAZ in the PZ group (-1.45) was higher than the MNP (-1.70) and control (-1.55) groups (p = 0.01) among children in the highest baseline IGF1 tertile (p for interaction = 0.006). At 36 weeks (but not at 18 weeks), WAZ in the PZ group (-1.55) was significantly higher than the MNP (-1.75) and control (-1.65) groups (p = 0.03), among children in the lowest baseline IGFBP3 tertile (p for interactions = 0.06).

CONCLUSIONS

Although IGF1 and IGFBP3 did not respond to PZ and MNP, baseline IGF1 and IGFBP3 significantly modified the impact of PZ on linear and ponderal growth, suggesting that IGF1 bioavailability may drive catch-up growth in zinc-supplemented children.

Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years

BACKGROUND

Zinc deficiency is prevalent in low- and middle-income countries, and is considered a significant risk factor for morbidity, mortality, and linear growth failure. The effectiveness of preventive zinc supplementation in reducing prevalence of zinc deficiency needs to be assessed.

OBJECTIVES

To assess the effects of zinc supplementation for preventing mortality and morbidity, and for promoting growth, in children aged 6 months to 12 years.

SEARCH METHODS

A previous version of this review was published in 2014. In this update, we searched CENTRAL, MEDLINE, Embase, five other databases, and one trials register up to February 2022, together with reference checking and contact with study authors to identify additional studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) of preventive zinc supplementation in children aged 6 months to 12 years compared with no intervention, a placebo, or a waiting list control. We excluded hospitalized children and children with chronic diseases or conditions. We excluded food fortification or intake, sprinkles, and therapeutic interventions.

DATA COLLECTION AND ANALYSIS

Two review authors screened studies, extracted data, and assessed the risk of bias. We contacted study authors for missing information and used GRADE to assess the certainty of evidence. The primary outcomes of this review were all-cause mortality; and cause-specific mortality, due to all-cause diarrhea, lower respiratory tract infection (LRTI, including pneumonia), and malaria. We also collected information on a number of secondary outcomes, such as those related to diarrhea and LRTI morbidity, growth outcomes and serum levels of micronutrients, and adverse events.

MAIN RESULTS

We included 16 new studies in this review, resulting in a total of 96 RCTs with 219,584 eligible participants. The included studies were conducted in 34 countries; 87 of them in low- or middle-income countries. Most of the children included in this review were under five years of age. The intervention was delivered most commonly in the form of syrup as zinc sulfate, and the most common dose was between 10 mg and 15 mg daily. The median duration of follow-up was 26 weeks. We did not consider that the evidence for the key analyses of morbidity and mortality outcomes was affected by risk of bias. High-certainty evidence showed little to no difference in all-cause mortality with preventive zinc supplementation compared to no zinc (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.84 to 1.03; 16 studies, 17 comparisons, 143,474 participants). Moderate-certainty evidence showed that preventive zinc supplementation compared to no zinc likely results in little to no difference in mortality due to all-cause diarrhea (RR 0.95, 95% CI 0.69 to 1.31; 4 studies, 132,321 participants); but probably reduces mortality due to LRTI (RR 0.86, 95% CI 0.64 to 1.15; 3 studies, 132,063 participants) and mortality due to malaria (RR 0.90, 95% CI 0.77 to 1.06; 2 studies, 42,818 participants); however, the confidence intervals around the summary estimates for these outcomes were wide, and we could not rule out a possibility of increased risk of mortality. Preventive zinc supplementation likely reduces the incidence of all-cause diarrhea (RR 0.91, 95% CI 0.90 to 0.93; 39 studies, 19,468 participants; moderate-certainty evidence) but results in little to no difference in morbidity due to LRTI (RR 1.01, 95% CI 0.95 to 1.08; 19 studies, 10,555 participants; high-certainty evidence) compared to no zinc. There was moderate-certainty evidence that preventive zinc supplementation likely leads to a slight increase in height (standardized mean difference (SMD) 0.12, 95% CI 0.09 to 0.14; 74 studies, 20,720 participants). Zinc supplementation was associated with an increase in the number of participants with at least one vomiting episode (RR 1.29, 95% CI 1.14 to 1.46; 5 studies, 35,192 participants; high-certainty evidence). We report a number of other outcomes, including the effect of zinc supplementation on weight and serum markers such as zinc, hemoglobin, iron, copper, etc. We also performed a number of subgroup analyses and there was a consistent finding for a number of outcomes that co-supplementation of zinc with iron decreased the beneficial effect of zinc.

AUTHORS' CONCLUSIONS

Even though we included 16 new studies in this update, the overall conclusions of the review remain unchanged. Zinc supplementation might help prevent episodes of diarrhea and improve growth slightly, particularly in children aged 6 months to 12 years of age. The benefits of preventive zinc supplementation may outweigh the harms in regions where the risk of zinc deficiency is relatively high.

Daily preventive zinc supplementation increases the antibody response against pathogenic Escherichia coli in children with zinc insufficiency: a randomised controlled trial

Zinc deficiency impairs the antibody-mediated immune response and is common in children from lower-income countries. This study aimed to investigate the impact of different zinc supplementation regimens (7, 10 or 20 mg/day elemental zinc)—therapeutic dispersible zinc tablets (TZ), daily multiple micronutrient powder (MNP), daily preventive zinc tablets (PZ) and placebo powder (control)—and compare between baseline and endline antibody production against pathogenic Escherichia coli in Laotian children (aged 6–23 months). Fifty representative plasma samples of each treatment group were randomly selected from 512 children to determine anti-E. coli IgG antibody levels and avidity. Of the 200 children, 78.5% had zinc deficiency (plasma zinc concentration < 65 µg/dL) and 40% had anaemia before receiving zinc supplementation. aAfter receiving the TZ, MNP or PZ regimen, the plasma anti-E. coli IgG levels were significantly increased compared with baseline; the effect on the antibody level was more pronounced in children with zinc deficiency. Interestingly, there was increased anti-E. coli IgG avidity in the control and PZ groups. This study suggests that PZ might be the optimal zinc supplementation regimen to increase both the quantity and quality of antibody responses in children with zinc deficiency. Clinical trial registration: https://clinicaltrials.gov/ct2/show/NCT02428647 (NCT02428647, 29/04/2015).

Daily supplementation of a multiple micronutrient powder improves folate but not thiamine, riboflavin, or vitamin B12 status among young Laotian children: a randomized controlled trial

PURPOSE

To assess the effects of intervention with a daily multiple micronutrient powder (MNP) on thiamine, riboflavin, folate, and B₁₂ status among young Laotian children.

METHODS

Children (n = 1704) aged 6-23 mo, participating in a double-blind placebo-controlled randomized trial were individually randomized to receive daily either MNP (containing 0.5 mg of thiamine, 0.5 mg riboflavin, 150 μg folic acid, and 0.9 μg vitamin B₁₂ along with 11 other micronutrients) or placebo and followed for ~ 36 weeks. In a randomly selected sub-sample of 260 children, erythrocyte thiamine diphosphate (eThDP), plasma folate and B₁₂ concentrations, and erythrocyte glutathione reductase activation coefficient (EGRac; riboflavin biomarker) were assessed at baseline and endline.

RESULTS

There was no treatment effect on endline eThDP concentrations (110.6 ± 8.9 nmol/L in MNP vs. 109.4 ± 8.9 nmol/L in placebo group; p = 0.924), EGRac (1.46 ± 0.3 vs. 1.49 ± 0.3; p = 0.184) and B₁₂ concentrations (523.3 ± 24.6 pmol/L vs. 515.9 ± 24.8 pmol/L; p = 0.678). Likewise, the prevalence of thiamine, riboflavin, and B₁₂ deficiencies did not differ significantly between the two groups. However, endline folate concentration was significantly higher in the MNP compared to the placebo group (28.2 ± 0.8 nmol/L vs 19.9 ± 0.8 nmol/L, respectively; p < 0.001), and correspondingly, the prevalence of folate deficiency was significantly lower in the MNP group (1.6% vs 17.4%; p = 0.015).

CONCLUSIONS

Compared to a placebo, daily MNP for 9 months increased only folate but not thiamine, riboflavin, or B₁₂ status in young Laotian children.

TRIAL REGISTRATION

The trial was registered at www.

CLINICALTRIALS

gov (NCT02428647) on April 29 2015.

Effects of therapeutic zinc supplementation for diarrhea and two preventive zinc supplementation regimens on the incidence and duration of diarrhea and acute respiratory tract infections in rural Laotian children: A randomized controlled trial

Background

Diarrhea and respiratory tract infections are leading causes of childhood morbidity and mortality. This individually randomized, double-blind placebo-controlled trial was designed to evaluate the effects of different zinc supplementation regimens on the incidence and duration of diarrhea and acute lower (ALRI) and upper (AURI) respiratory tract infections among rural Laotian children. The study included 3407 children, 6-23 months at enrollment.

Methods

Children were randomized to one of four study groups: therapeutic zinc supplements for diarrhea treatment (20 mg/d for 10 days with each episode; TZ), daily preventive zinc tablets (7 mg/d; PZ), daily multiple micronutrient powder (10 mg/d zinc, 6 mg/d iron and 13 other micronutrients; MNP), or daily placebo powder for 9 months. Incidence and duration of diarrhea (≥3 liquid stools/24 hours), ALRI (persistent cough with wheezing, stridor or chest in-drawing) and AURI (purulent nasal discharge with cough) were assessed by parental report during weekly home visits and analyzed using negative binomial models.

Results

Baseline mean age was 14.2 ± 5.1 months, and 71% had low plasma zinc (<65 μg/dL). Overall diarrhea incidence (0.61 ± 0.01 episodes/100 days at risk) and duration (2.12 ± 0.03 days/episode) did not differ by study group. Age modified the impact of the interventions on diarrhea incidence (P = 0.06) and duration (P = 0.01). In children >18 months, TZ reduced diarrhea incidence by 24% vs MNP (P = 0.035), and 36% vs Control (P = 0.004), but there was no difference with PZ. This patterned remained when analyses were restricted to diarrhea episode occurring after the first treatment with TZ. Also, in children >18 months, TZ reduced diarrhea duration by 15% vs PZ (P = 0.03), and 16% vs Control (P = 0.03), but there was no difference with MNP. There were no overall effects of study group on incidence of ALRI (overall mean 0.005 ± 0.001 episodes/100 days, P = 0.14) or AURI (overall mean 0.09 ± 0.01 episodes/100 days, P = 0.72).

Conclusions

There was no overall impact of TZ, PZ or MNP on diarrhea, ALRI and AURI. However, in children >18 months, TZ significantly reduced both the duration of diarrhea episodes and the incidence of future diarrhea episodes compared with placebo.

Trial registration

ClinicalTrials.gov: NCT02428647.

Plasma and Nail Zinc Concentrations, But Not Hair Zinc, Respond Positively to Two Different Forms of Preventive Zinc Supplementation in Young Laotian Children: a Randomized Controlled Trial

Plasma zinc concentrations (PZC) have been shown to significantly increase during zinc supplementation. This study investigated the effects of daily preventive zinc supplementation on hair and nail zinc concentrations compared with a control group. In a randomized controlled trial, 6- to 23-month-old children (n = 3407) in Lao PDR were randomly assigned to one of four groups and followed for ~ 36 weeks: daily preventive zinc dispersible tablet (7 mg/d; PZ), daily micronutrient powder (10 mg zinc/d; MNP), therapeutic zinc supplements for diarrhea treatment (20 mg/d for 10 days; TZ), or daily placebo powder (Control). Plasma, hair, and nail zinc concentrations were assessed in a sub-sample of participants (n = 457) at baseline and endline. At baseline, 75% of children had low PZC (< 65 μg/dL). At endline, geometric mean (95% CI) PZC were greater in the PZ and MNP groups compared with the TZ and control groups (P < 0.01), but hair zinc concentrations did not differ among groups (P = 0.99). Nail zinc concentrations were marginally higher in the PZ (115.8 (111.6, 119.9) μg/g) and the MNP (117.8 (113.3, 122.3) μg/g) groups than in the TZ group (110.4 (106.0, 114.8) μg/g; P = 0.055) at endline. This study does not support the use of hair zinc as a biomarker of zinc exposure in young children. However, it provides some evidence that zinc concentrations in nails may respond to supplemental zinc interventions and supports the need for collecting additional data on this emerging biomarker.

Daily Preventive Zinc Supplementation Decreases Lymphocyte and Eosinophil Concentrations in Rural Laotian Children from Communities with a High Prevalence of Zinc Deficiency: Results of a Randomized Controlled Trial

BACKGROUND

Zinc deficiency impairs immune function and is common among children in South-East Asia.

OBJECTIVES

The effect of zinc supplementation on immune function in young Laotian children was investigated.

METHODS

Children (n = 512) aged 6-23 mo received daily preventive zinc tablets (PZ; 7 mg Zn/d), daily multiple micronutrient powder (MNP; 10 mg Zn/d, 6 mg Fe/d, plus 13 other micronutrients), therapeutic dispersible zinc tablets only in association with diarrhea episodes (TZ; 20 mg Zn/d for 10 d after an episode), or daily placebo powder (control). These interventions continued for 9 mo. Cytokine production from whole blood cultures, the concentrations of T-cell populations, and a complete blood count with differential leukocyte count were measured at baseline and endline. Endline means were compared via ANCOVA, controlling for the baseline value of the outcome, child age and sex, district, month of enrollment, and baseline zinc status (below, or above or equal to, the median plasma zinc concentration).

RESULTS

T-cell cytokines (IL-2, IFN-γ, IL-13, IL-17), LPS-stimulated cytokines (IL-1β, IL-6, TNF-α, and IL-10), and T-cell concentrations at endline did not differ between intervention groups, nor was there an interaction with baseline zinc status. However, mean ± SE endline lymphocyte concentrations were significantly lower in the PZ than in the control group (5018 ± 158 compared with 5640 ± 160 cells/μL, P = 0.032). Interactions with baseline zinc status were seen for eosinophils (Pixn = 0.0036), basophils (Pixn = 0.023), and monocytes (P = 0.086) but a significant subgroup difference was seen only for eosinophils, where concentrations were significantly lower in the PZ than in the control group among children with baseline plasma zinc concentrations below the overall median (524 ± 44 compared with 600 ± 41 cells/μL, P = 0.012).

CONCLUSIONS

Zinc supplementation of rural Laotian children had no effect on cytokines or T-cell concentrations, although zinc supplementation affected lymphocyte and eosinophil concentrations. These cell subsets may be useful as indicators of response to zinc supplementation.This trial was registered at clinicaltrials.gov as NCT02428647.

Zinc deficiency in low- and middle-income countries: prevalence and approaches for mitigation

This review addresses the prevalence of zinc deficiency in Low- and Middle-income Countries (LMICs) and assesses the available strategies for its alleviation. The paucity of national-level data on the zinc deficiency in LMICs is partially a result of the lack of a reliable biomarker. Zinc deficiency appears to be a public health problem in almost all the LMICs, irrespective of the recommended indicators (plasma zinc concentration, dietary zinc adequacy and stunting prevalence) used. Based on plasma/serum zinc concentration (PZC), which is the most appropriate indicator at present, the prevalence of zinc deficiency in LMICs is of concern. Among the 25 countries for which national PZC data were available, 23 had a zinc deficiency prevalence of >20% for at least one physiological group. Zinc supplementation is largely restricted as an adjunct therapy for diarrhoea management in children, and the best platform and the most effective way of preventive zinc supplementation delivery remains to be established. Impact assessment for current zinc fortification programmes in LMICs and the effectiveness of zinc supplementation as part of a multi-micronutrient powder is to be determined. Dietary diversification, though promising for LMICs, is in the nascent stages of development at present. Inclusion of meat and animal products can be an important way of improving zinc status. Programmatic experience with the promotion of home processing techniques to increase absorbable zinc in the diet is lacking. Conventional biofortification techniques are gaining recognition in LMICs; however, transgenic biofortification as a strategy remains controversial.

Impact of Different Strategies for Delivering Supplemental Zinc on Selected Fecal Markers of Environmental Enteric Dysfunction among Young Laotian Children: A Randomized Controlled Trial

The objective of this study was to assess the impact of different strategies for delivering supplemental zinc on fecal myeloperoxidase (MPO), neopterin (NEO), and calprotectin (CAL) among young Laotian children. In a double-blind controlled trial, children aged 6-23 months were randomized to receive either daily preventive zinc (PZ) tablets (7 mg/day), daily micronutrient powder (MNP; containing 10 mg zinc and 14 other micronutrients), therapeutic zinc (TZ) supplements for diarrhea treatment (20 mg/day for 10 days), or daily placebo powder and followed for ∼36 weeks. Stool samples were collected at baseline and endline. Fecal MPO, NEO, and CAL concentrations were determined in a randomly selected subsample of 720 children using commercially available ELISA kits. At baseline, the mean age was 14.1 ± 4.9 months and prevalence of stunting was 39%. The endline prevalence of stunting was 43%; there was no overall treatment effect on physical growth in the parent trial. At endline, the mean (95% CI) MPO in the PZ group was 1,590 [1,396; 1,811] ng/mL and did not differ from that in the MNP (1,633 [1,434; 1,859] ng/mL), TZ (1,749 [1,535; 1,992] ng/mL), and control (1,612 [1,415; 1,836] ng/mL) groups (P = 0.749). Similarly, there was no overall treatment effect on NEO and CAL concentrations (P = 0.226 and 0.229, respectively). In this population, the provision of PZ or TZ supplements or MNP had no impact on growth or environmental enteric dysfunction (EED) as assessed by fecal MPO, NEO, and CAL. Additional research is needed to better understand the etiology and proposed mechanisms of EED pathogenesis.

Iron status and inherited haemoglobin disorders modify the effects of micronutrient powders on linear growth and morbidity among young Lao children in a double-blind randomised trial

Some studies found that providing micronutrient powder (MNP) causes adverse health outcomes, but modifying factors are unknown. We aimed to investigate whether Fe status and inherited Hb disorders (IHbD) modify the impact of MNP on growth and diarrhoea among young Lao children. In a double-blind controlled trial, 1704 children of age 6–23 months were randomised to daily MNP (with 6 mg Fe plus fourteen micronutrients) or placebo for about 36 weeks. IHbD, and baseline and final Hb, Fe status and anthropometrics were assessed. Caregivers provided weekly morbidity reports. At enrolment, 55·6 % were anaemic; only 39·3 % had no sign of clinically significant IHbD. MNP had no overall impact on growth and longitudinal diarrhoea prevalence. Baseline Hb modified the effect of MNP on length-for-age (LAZ) (P for interaction = 0·082). Among children who were initially non-anaemic, the final mean LAZ in the MNP group was slightly lower (–1·93 (95 % CI –1·88, –1·97)) v. placebo (–1·88 (95 % CI –1·83, –1·92)), and the opposite occurred among initially anaemic children (final mean LAZ –1·90 (95 % CI –1·86, –1·94) in MNP v. –1·92 (95 % CI –1·88, –1·96) in placebo). IHbD modified the effect on diarrhoea prevalence (P = 0·095). Among children with IHbD, the MNP group had higher diarrhoea prevalence (1·37 (95 % CI 1·17, 1·59) v. 1·21 (95 % CI 1·04, 1·41)), while it was lower among children without IHbD who received MNP (1·15 (95 % CI 0·95, 1·39) v. 1·37 (95 % CI 1·13, 1·64)). In conclusion, there was a small adverse effect of MNP on growth among non-anaemic children and on diarrhoea prevalence among children with IHbD.

Childhood diarrhoeal diseases in developing countries

Diarrhoeal diseases collectively constitute a serious public health challenge globally, especially as the leading cause of death in children (after respiratory diseases). Childhood diarrhoea affecting children under the age of five accounts for approximately 63% of the global burden. Accurate and timely detection of the aetiology of these diseases is very crucial; but conventional methods, apart from being laborious and time-consuming, often fail to identify difficult-to-culture pathogens. The aetiological agent of an average of up to 40% of cases of diarrhoea cannot be identified. This review gives an overview of the recent trends in the epidemiology and treatment of diarrhoea and aims at highlighting the potentials of metagenomics technique as a diagnostic method for enteric infections.

Establishing a case definition of thiamine responsive disorders among infants and young children in Lao PDR: protocol for a prospective cohort study

INTRODUCTION

Diagnosis of infantile thiamine deficiency disorders (TDD) is challenging due to the non-specific, highly variable clinical presentation, often leading to misdiagnosis. Our primary objective is to develop a case definition for thiamine responsive disorders (TRD) to determine among hospitalised infants and young children, which clinical features and risk factors identify those who respond positively to thiamine administration.

METHODS AND ANALYSIS

This prospective study will enrol 662 children (aged 21 days to <18 months) seeking treatment for TDD symptoms. Children will be treated with intravenous or intramuscular thiamine (100 mg daily for a minimum of 3 days) alongside other interventions deemed appropriate. Baseline assessments, prior to thiamine administration, include a physical examination, echocardiogram and venous blood draw for the determination of thiamine biomarkers. Follow-up assessments include physical examinations (after 4, 8, 12, 24, 36, 48 and 72 hours), echocardiogram (after 24 and 48 hours) and one cranial ultrasound. During the hospital stay, maternal blood and breast-milk samples and diet, health, anthropometric and socio-demographic information will be collected for mother-child pairs. Using these data, a panel of expert paediatricians will determine TRD status for use as the dependent variable in logistic regression models. Models identifying predictors of TRD will be developed and validated for various scenarios. Clinical prediction model performance will be quantified by empirical area under the receiver operating characteristic curve, using resampling cross validation. A frequency-matched community-based cohort of mother-child pairs (n=265) will serve as comparison group for evaluation of potential risk factors for TRD.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from The National Ethics Committee for Health Research, Ministry of Health, Lao PDR and the Institutional Review Board of the University of California Davis. The results will be disseminated via scientific articles, presentations and workshops with representatives of the Ministry of Health.

TRIAL REGISTRATION NUMBER

NCT03626337.

Hemoglobins F, A2 , and E levels in Laotian children aged 6-23 months with Hb E disorders: Effect of age, sex, and thalassemia types

Introduction

Determination of hemoglobins (Hbs) F, A_2, and E is crucial for diagnosis of thalassemia. This study determined the levels of Hbs F, A_2, and E in children aged 6‐23 months and investigated the effect of age, sex, and types of thalassemia on the expression of these Hbs.

Methods

A total of 698 blood samples of Laotian children including 272 non‐Hb E, 271 Hb E heterozygotes, and 155 Hb E homozygotes were collected. Hb profiles were determined using the capillary zone electrophoresis. Coinheritance of α‐thalassemia and the homozygosity for Hb E mutation were checked by PCR‐based assay.

Results

Children heterozygous and homozygous for Hb E had significantly higher Hb F and A₂ levels than non‐Hb E children (median Hb F = 1.1% for non‐Hb E group, 2.7% for Hb E heterozygotes, and 9.4% for Hb E homozygotes; median Hb A₂ = 2.6% for non‐Hb E group, 3.8% for Hb E heterozygotes, and 5.2% for Hb E homozygotes). The median Hb E levels were 21.9% for Hb E heterozygotes and 85.3% for Hb E homozygotes. Comparing within group, there was a statistically significant difference between children with and without an α‐gene defect for Hb A₂ and E, but not Hb F. Based on a multiple regression analysis, age and sex were significantly associated with the expression of Hb F and A₂ but not Hb E.

Conclusions

Our findings can guide the development of a diagnostic approach to thalassemia in children aged 6‐23 months.

Impact of Daily Preventive Zinc or Therapeutic Zinc Supplementation for Diarrhea on Plasma Biomarkers of Environmental Enteric Dysfunction among Rural Laotian Children: A Randomized Controlled Trial

Environmental enteric dysfunction (EED) may be ameliorated by zinc supplementation. The objective of this study was to investigate the impact of different forms of zinc supplementation on biomarkers of EED (i.e., plasma citrulline, kynurenine, and tryptophan concentrations and the kynurenine:tryptophan [KT] ratio) among young Laotian children. In a double-blind randomized controlled trial, 3,407 children aged 6-23 months were randomized into one of four groups: daily preventive zinc dispersible tablets (PZ; 7 mg zinc), daily multiple micronutrient powders (MNP; 10 mg zinc, 6 mg iron, and 13 other micronutrients), therapeutic zinc supplements for diarrhea treatment (TZ; 20 mg/day for 10 days), or daily placebo powder, and followed up for ∼36 weeks. Plasma samples at baseline and endline for 359 children were analyzed for citrulline, kynurenine, and tryptophan concentrations. At baseline, the prevalence of stunting and zinc deficiency was 37% and 76.5%, respectively. The mean plasma citrulline, kynurenine, and tryptophan concentrations were 24.6 ± 5.4 µmol/L, 3.27 ± 0.83 µmol/L, and 72.3 ± 12.9 µmol/L, respectively; the mean KT ratio (×1,000) was 45.9 ± 12.0. At endline, neither plasma citrulline, kynurenine, or tryptophan concentrations, nor the KT ratio differed among intervention groups (P > 0.05). In this population, PZ, MNP, and TZ had no overall effect on plasma concentrations of citrulline, kynurenine, and tryptophan, or the KT ratio. The need remains to better understand the etiology of EED, and the development of biomarkers to diagnose EED and evaluate the impact of interventions.

Impact of Two Forms of Daily Preventive Zinc or Therapeutic Zinc Supplementation for Diarrhea on Hair Cortisol Concentrations Among Rural Laotian Children: A Randomized Controlled Trial

Zinc supplementation has been shown to reduce the morbidity burden among young children, and may reduce chronic stress. Hair cortisol has been promoted as an indicator of chronic stress. We assessed the impact of different strategies for delivering supplementary zinc on hair cortisol concentrations (HCC) in young Laotian children and examined risk factors associated with HCC. In a randomized double-blind controlled trial (NCT02428647), children aged 6⁻23 mo were randomized to one of four intervention groups and followed for ~36 weeks: daily preventive zinc (PZ) tablets (7 mg/day), daily multiple micronutrient powder (MNP) sachets (containing 10 mg zinc and 14 other micronutrients), therapeutic zinc (TZ) supplements for diarrhea treatment (20 mg/day for 10 days) or daily placebo powder. HCC of 512 children was assessed at baseline and endline. ANCOVA and linear regression models were used to assess group differences in HCC and to examine the risk factors associated with HCC, respectively. At enrollment, mean HCC was 28.8 ± 43.9 pg/mg. In models adjusted for age at enrollment, health district, and baseline HCC there was no overall effect of the interventions on endline HCC and change in HCC. When controlling for additional predetermined covariates, there was a marginally significant effect on change in HCC (p = 0.075) with a slightly lower reduction of HCC in TZ compared to PZ (mean change (95% CI): -4.6 (-7.0; -2.3) vs. -9.4 (-11.7; -7.0) pg/mg; p = 0.053). At baseline, consumption of iron rich foods was negatively associated with HCC, whereas AGP (α1-acid glycoprotein) levels, elevated AGP and C-reactive protein and high soluble transferrin receptor were positively associated with HCC. In young Laotian children, MNP, PZ and TZ had no impact on HCC. The marginal difference in change in HCC between the PZ and TZ groups was too small to be considered of health significance.