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Background: Detection of anaemia is crucial for clinical medicine and public health. Current WHO anaemia definitions are based on statistical thresholds (fifth centiles) set more than 50 years ago. We sought to establish evidence for the statistical haemoglobin thresholds for anaemia that can be applied globally and inform WHO and clinical guidelines. Methods: In this analysis we identified international data sources from populations in the USA, England, Australia, China, the Netherlands, Canada, Ecuador, and Bangladesh with sufficient clinical and laboratory information collected between 1998 and 2020 to obtain a healthy reference sample. Individuals with clinical or biochemical evidence of a condition that could reduce haemoglobin concentrations were excluded. We estimated haemoglobin thresholds (ie, 5th centiles) for children aged 6–23 months, 24–59 months, 5–11 years, and 12–17 years, and adults aged 18–65 years (including during pregnancy) for individual datasets and pooled across data sources. We also collated findings from three large-scale genetic studies to summarise genetic variants affecting haemoglobin concentrations in different ancestral populations. Findings: We identified eight data sources comprising 18 individual datasets that were eligible for inclusion in the analysis. In pooled analyses, the haemoglobin fifth centile was 104·4 g/L (90% CI 103·5–105·3) in 924 children aged 6–23 months, 110·2 g/L (109·5–110·9) in 1874 children aged 24–59 months, and 114·4 g/L (113·6–115·2) in 1839 children aged 5–11 years. Values diverged by sex in adolescents and adults. In pooled analyses, the fifth centile was 122·2 g/L (90% CI 121·3–123·1) in 1741 female adolescents aged 12–17 years and 128·2 g/L (126·4–130·0) in 1103 male adolescents aged 12–17 years. In pooled analyses of adults aged 18–65 years, the fifth centile was 119·7 g/L (90% CI 119·1–120·3) in 3640 non-pregnant females and 134·9 g/L (134·2–135·6) in 2377 males. Fifth centiles in pregnancy were 110

Background: Universal provision of iron supplements or iron-containing multiple micronutrient powders (MNPs) is widely used to prevent anemia in young children in low- and middle-income countries. The BRISC (Benefits and Risks of Iron Interventions in Children) trial compared iron supplements and MNPs with placebo in children <2 y old in rural Bangladesh. Objectives: We aimed to assess the cost-effectiveness of iron supplements or iron-containing MNPs among young children in rural Bangladesh. Methods: We did a cost-effectiveness analysis of MNPs and iron supplements using the BRISC trial outcomes and resource use data, and programmatic data from the literature. Health care costs were assessed from a health system perspective. We calculated incremental cost-effectiveness ratios (ICERs) in terms of US$ per disability-adjusted life-year (DALY) averted. To explore uncertainty, we constructed cost-effectiveness acceptability curves using bootstrapped data over a range of cost-effectiveness thresholds. One- and 2-way sensitivity analyses tested the impact of varying key parameter values on our results. Results: Provision of MNPs was estimated to avert 0.0031 (95% CI: 0.0022, 0.0041) DALYs/child, whereas iron supplements averted 0.0039 (95% CI: 0.0030, 0.0048) DALYs/child, over 1 y compared with no intervention. Incremental mean costs were $0.75 (95% CI: 0.73, 0.77) for MNPs compared with no intervention and $0.64 ($0.62, $0.67) for iron supplements compared with no intervention. Iron supplementation dominated MNPs because it was cheaper and averted more DALYs. Iron supplementation had an ICER of $1645 ($1333, $2153) per DALY averted compared with no intervention, and had a 0% probability of being the optimal strategy at cost-effectiveness thresholds of $200 (reflecting health opportunity costs in Bangladesh) and $985 [half of gross domestic product (GDP) per capita] per DALY averted. Scenario and sensitivity analyses supported the base case findings. Conclusions: These

Preventive zinc supplementation provided as a stand-alone dispersible tablet, or via home fortification as multiple micronutrient powders (MNPs), has been considered a potential strategy to prevent zinc deficiency and improve health (including immune) outcomes among children in low- and middle-income countries. However, the impact of zinc supplementation on immune profiles has not been well characterized. We sought to define the effect of zinc supplementation on peripheral blood gene expression and cytokine levels among young children in Dhaka, Bangladesh. In a sub-study of a large randomized, controlled, community-based efficacy trial where children 9-11 months of age received one of the following interventions on a daily basis for 24 weeks: (1) MNPs containing 10 mg of zinc; (2) dispersible tablet containing 10 mg zinc; or (3) placebo powder, we used RNA sequencing to profile the peripheral blood gene expression, as well as highly sensitive multiplex assays to detect cytokine profiles. We profiled samples from 100 children enrolled in the parent trial (zinc MNPs 28, zinc tablets 39, placebo 33). We did not detect an effect from either zinc intervention on differential peripheral blood gene expression at the end of the intervention, or an effect from the intervention on changes in gene expression from baseline. We also did not detect an effect from either intervention on cytokine concentrations. Exploratory analysis did not identify an association between undernutrition (defined as stunting, underweight or wasting) and peripheral blood gene expression. Zinc interventions in children did not produce a gene expression or cytokine signature in the peripheral blood. However, this study demonstrates a proof of principle that sensitive multi-omic techniques can be applied to samples collected in field studies.

Preventive zinc supplementation provided as a stand-alone dispersible tablet, or via home fortification as multiple micronutrient powders (MNPs), has been considered a potential strategy to prevent zinc deficiency and improve health (including immune) outcomes among children in low- and middle-income countries. However, the impact of zinc supplementation on immune profiles has not been well characterized. We sought to define the effect of zinc supplementation on peripheral blood gene expression and cytokine levels among young children in Dhaka, Bangladesh. In a sub-study of a large randomized, controlled, community-based efficacy trial where children 9-11 months of age received one of the following interventions on a daily basis for 24 weeks: (1) MNPs containing 10 mg of zinc; (2) dispersible tablet containing 10 mg zinc; or (3) placebo powder, we used RNA sequencing to profile the peripheral blood gene expression, as well as highly sensitive multiplex assays to detect cytokine profiles. We profiled samples from 100 children enrolled in the parent trial (zinc MNPs 28, zinc tablets 39, placebo 33). We did not detect an effect from either zinc intervention on differential peripheral blood gene expression at the end of the intervention, or an effect from the intervention on changes in gene expression from baseline. We also did not detect an effect from either intervention on cytokine concentrations. Exploratory analysis did not identify an association between undernutrition (defined as stunting, underweight or wasting) and peripheral blood gene expression. Zinc interventions in children did not produce a gene expression or cytokine signature in the peripheral blood. However, this study demonstrates a proof of principle that sensitive multi-omic techniques can be applied to samples collected in field studies.

Background: Universal home fortification of complementary foods with iron-containing multiple micronutrient powders (MNPs) is a key intervention to prevent anaemia in young children in low-income and middle-income countries. However, evidence that MNPs might promote infection raises uncertainty about whether MNPs give net health benefits and are cost-effective. We aimed to determined country-specific net benefit or harm and cost-effectiveness of universal provision of MNPs to children aged 6 months. Methods: We developed a microsimulation model to estimate net country-specific disability-adjusted life-years (DALYs), years lived with disability (YLDs), and years of life lost (YLLs) due to anaemia, malaria, and diarrhoea averted (or increased) by provision of a 6-month course of MNPs to children aged 6 months, compared with no intervention, who would be followed up for an additional 6 months (ie, to age 18 months). Anaemia prevalence was derived from Demographic and Health Surveys or similar national surveys, and malaria and diarrhoea incidence were sourced from the Global Burden of Disease Study. Programme and health-care costs were modelled to determine cost per DALY averted (US$). Additionally, we explored the effects of reduced MNP coverage in a sensitivity analysis. Findings: 78 countries (46 countries in Africa, 20 in Asia or the Middle East, and 12 in Latin America) were included in the analysis, and we simulated 5 million children per country. 6 months of universal distribution of daily MNPs, assuming 100% coverage, produced a net benefit (DALYs averted) in 54 countries (24 in Africa, 19 in Asia and the Middle East, 11 in Latin America) and net harm in 24 countries (22 in Africa, one in Asia, and one in Latin America). MNP intervention provided a benefit on YLDs associated with anaemia, but these gains were attenuated and sometimes reversed by increases in YLLs associated with malaria and diarrhoea, reducing the benefits seen for DALYs. In the 54 countries

Background: WHO recommends daily iron supplementation for pregnant women, but adherence is poor because of side-effects, effectiveness is low, and there are concerns about possible harm. The iron-regulatory hormone hepcidin can signal when an individual is ready-and-safe to receive iron. We tested whether a hepcidin-guided screen-and-treat approach to combat iron-deficiency anaemia could achieve equivalent efficacy to universal administration, but with lower exposure to iron. Methods: We did a three-arm, randomised, double-blind, non-inferiority trial in 19 rural communities in the Jarra West and Kiang East districts of The Gambia. Eligible participants were pregnant women aged 18–45 years at between 14 weeks and 22 weeks of gestation. We randomly allocated women to either WHO's recommended regimen (ie, a daily UN University, UNICEF, and WHO international multiple-micronutrient preparation [UNIMMAP] containing 60 mg iron), a 60 mg screen-and-treat approach (ie, daily UNIMMAP containing 60 mg iron for 7 days if weekly hepcidin was <2·5 μg/L or UNIMMAP without iron if hepcidin was ≥2·5 μg/L), or a 30 mg screen-and-treat approach (ie, daily UNIMMAP containing 30 mg iron for 7 days if weekly hepcidin was <2·5 μg/L or UNIMMAP without iron if hepcidin was ≥2·5 μg/L). We used a block design stratified by amount of haemoglobin at enrolment (above and below the median amount of haemoglobin on every enrolment day) and stage of gestation (14–18 weeks vs 19–22 weeks). Participants and investigators were unaware of the random allocation. The primary outcome was the amount of haemoglobin at day 84 and was measured as the difference in haemoglobin in each screen-and-treat group compared with WHO's recommended regimen; the non-inferiority margin was set at −5·0 g/L. The primary outcome was assessed in the per-protocol population, which comprised all women who completed the study. This trial is registered with the ISRCTN registry, number ISRCTN21955180. Findings: Between June 16

The World Health Organization estimates that globally, over 1.6 billion people are anaemic, with the prevalence highest among preschool children. Almost one third of the 293 million anaemic preschool children worldwide live in India. Despite rapid economic growth and long-standing anaemia control policies, the burden of anaemia in Indian children remains undiminished. In rural India, 80.9% of children aged 6-35 months are anaemic. Iron deficiency is believed to be the most important cause of anaemia in this population. However, other conditions, including deficiencies of folate, vitamins B12 and A, malarial and hookworm infection, and haemoglobinopathies, may also cause anaemia. The relative contribution of nutritional, infectious and genetic conditions to the burden of anaemia among Indian children has not been determined. A comprehensive understanding of the determinants of anaemia, including an appreciation of the performance of anaemia control programmes, is needed to address anaemia among young children in rural India. This thesis comprises two studies that aim to ultimately inform policy by understanding the determinants of anaemia, evaluating implementation of anaemia control strategies in the field, and ascertaining the value of screening for anaemia. The first project comprises a cross-sectional study investigating the determinants of anaemia and micronutrient concentrations, and evaluating the performance of anaemia control strategies in children 12-23 months of age in rural Karnataka, India. Of 401 children sampled, 75.3% were anaemic. A multiple regression model identified independent, positive associations between children’s haemoglobin and their ferritin, folate, age, maternal haemoglobin, and either family wealth or food security status; and negative associations with presence of beta thalassaemia trait, C-Reactive Protein (CRP) and male sex. Children’s ferritin was positively associated with maternal haemoglobin, iron intake and CRP, and negatively w