High Iron Stores in the Low Malaria Season Increase Malaria Risk in the High Transmission Season in a Prospective Cohort of Rural Zambian Children

Safe and effective delivery of supplemental iron to healthy adults: a two-phase, randomized, double-blind trial - the safe iron study

Introduction

The safety of novel forms of iron in healthy, iron-replete adults as might occur if used in population-based iron supplementation programs was examined. We tested the hypotheses that supplementation with nanoparticulate iron hydroxide adipate tartrate (IHAT), an iron-enriched Aspergillus oryzae product (ASP), or ferrous sulphate heptahydrate (FS) are safe as indicated by erythrocyte susceptibility to malarial infection, bacterial proliferation, and gut inflammation. Responses to FS administered daily or weekly, and with or without other micronutrients were compared.

Methods

Two phases of randomized, double-blinded trials were conducted in Boston, MA. Phase I randomized 160 volunteers to six treatments: placebo, IHAT, ASP, FS, and FS plus a micronutrient powder (MNP) administrated daily at 60 mg Fe/day; and FS administered as a single weekly dose of 420 mg Fe. Phase II randomized 86 volunteers to IHAT, ASP, or FS administered at 120 mg Fe/day. Completing these phases were 151 and 77 participants, respectively. The study was powered to detect effects on primary endpoints: susceptibility of participant erythrocytes to infection by Plasmodium falciparum, the proliferation potential of selected pathogenic bacteria in sera, and markers of gut inflammation. Secondary endpoints for which the study was not powered included indicators of iron status and gastrointestinal symptoms.

Results

Supplementation with any form of iron did not affect any primary endpoint. In Phase I, the frequency of gastrointestinal symptoms associated with FS was unaffected by dosing with MNP or weekly administration; but participants taking IHAT more frequently reported abdominal pain (27%, p < 0.008) and nausea (4%, p = 0.009) than those taking FS, while those taking ASP more frequently reported nausea (8%, p = 0.009). Surprisingly, only 9% of participants taking IHAT at 120 mg Fe/day (Phase II) reported abdominal pain and no other group reported that symptom.

Discussion

With respect to the primary endpoints, few differences were found when comparing these forms of iron, indicating that 28 days of 60 or 120 mg/day of IHAT, ASP, or FS may be safe for healthy, iron-replete adults. With respect to other endpoints, subjects receiving IHAT more frequently reported abdominal pain and nausea, suggesting the need for further study.

Clinical Trial Registration

ClinicalTrials.gov, NCT03212677; registered: 11 July 2017.

Effect of dietary intervention on the prevalence of asymptomatic malaria among 6-18-month-old children in rural Malawi

BACKGROUND

The complex interaction between malaria and undernutrition leads to increased mortality and morbidity rate among young children in malaria-endemic regions. Results from previous interventions suggest that improving nutritional status of young children may reduce the burden of malaria. This study tested a hypothesis that provision of lipid-based nutrient supplements (LNS) or corn-soy blend (CSB) supplementation to 6-18-month-old children in Malawi would reduce the prevalence of asymptomatic malaria among them.

METHODS

A total of 840 6-month-old children were enrolled in a randomized trial. The participants received 12-month supplementation with three different daily dietary supplementations: CSB, soy-LNS, or milk-LNS, and one control group without supplementation. The prevalence rate of asymptomatic Plasmodium falciparum was determined by real-time PCR from the participant's dried blood spots (DBS) collected at the baseline and every 3 months. The global null hypothesis was tested using modified Poisson regression to estimate the prevalence ratio (PR) between the control group and three intervention groups at all ages combined. All the models were adjusted for malaria at baseline, season of DBS sample collection, site of enrolment, and household asset Z-score.

RESULTS

All children combined, the prevalence of P. falciparum was 14.1% at enrollment, 8.7% at 9 months, 11.2% at 12 months, 13.0% at 15 months and 22.4% at 18 months of age. Among all samples that were taken after enrolment, the prevalence was 12.1% in control group, 12.2% in milk-LNS, 14.0% in soy-LNS, and 17.2% in CSB group. Compared to children in the control group the prevalence ratio of positive malaria tests was 1.19 (95% CI 0.81-1.74; P = 0.372) in the milk-LNS group, 1.32 (95% CI 0.88-1.96; P = 0.177) in the soy-LNS group and 1.72 (95% CI 1.19-2.49; P = 0.004) in the CSB group.

CONCLUSION

The study findings do not support a hypothesis that LNS or CSB supplementation would reduce the prevalence of asymptomatic malaria among Malawian children. In contrast, there was a signal of a possible increase in malaria prevalence among children supplemented with CSB.

Anaemia, iron deficiency and inflammation prevalence in children in the Mount Cameroon area and the contribution of inflammatory cytokines on haemoglobin and ferritin concentrations: a cross sectional study

BACKGROUND

Iron deficiency (ID) and anaemia of inflammation (AI) coexist where infections and nutritional deficiencies are common. The aim of this study was to determine burden of ID, anaemia, inflammation and AI in children in malaria endemic Limbe, Mount Cameroon as well as decipher the contribution of some inflammatory cytokines on the concentration of haemoglobin and ferritin.

METHODS

A total of 520 children aged ≤ 15 years old from the Limbe Health District (LHD) were randomly selected and examined in a cross-sectional study for iron deficiency, anaemia, inflammation and inflammation anaemia. Collected blood samples were used for full blood count and inflammatory marker analyses with the aid of a haemoanalyzer and ELISA machine, respectively. Spearman's rank correlation analysis was used to determine the correlation between cytokines and haemoglobin while multiple linear regression analysis was used to evaluate the effects of inflammatory cytokines on haemoglobin and ferritin concentrations.

RESULTS

The overall prevalence of anaemia, ID, IDA, inflammation and AI were respectively, 67.5%, 34.6%, 12.9%, 63.1% and 30.2%. Children aged 12‒15 years (P = 0.001), enrolled from the community (P < 0.001), whose parents are civil servants (P < 0.001), living in a home with 6‒10 occupants (P = 0.016), afebrile (P < 0.001) and malaria negative (P = 0.007) had the highest prevalence of ID while, children ≤ 5 years old (P = 0.001), with a family size of 1‒5 occupants (P = 0.033) had the highest prevalence of AI. Haemoglobin concentration positively correlated with concentrations of IFN-γ (P < 0.001), TNF-α (0.045) and ferritin (P < 0.001) while a negative correlation was observed with IL-10 (P = 0.003). In the multiple linear regression analysis only IL-6 significantly (P = 0.030) influenced haemoglobin concentration.

CONCLUSIONS

While IL-6 is of significance in the pathology of anaemia, iron deficiency and anaemia of inflammation are of moderate public health concerns in the Mount Cameroon area. Hence, appropriate intervention against anaemia, ID and AI should be directed at children ≤ 5 years and counterparts > 10 years old that bear the highest burden.

Age-specific differences in the magnitude of malaria-related anemia during low and high malaria seasons in rural Zambian children

Background

Malaria causes anemia by destruction of red blood cells and inhibition of erythropoiesis.

Objective

We assessed whether the magnitude of the malaria-specific effect on anemia differs by age, during low and high malaria seasons.

Method

In rural Zambian children participating in a pro-vitamin A efficacy trial, we estimated differences in the prevalence of anemia (defined as hemoglobin < 110 g/L for children < 60 months. and < 115 g/L in older children) by malaria status and assessed malaria-age interactions. Regression models (with anemia as the outcome) were used to model malaria-age interaction in both the low and high malaria seasons, controlling for potential confounders.

Results

Average age was 68 months at baseline (n = 820 children). In the low malaria season, anemia prevalence was 29% in malaria-negative children and 54% in malaria-positive children (p < 0.001), with no malaria-age interactions (p = 0.44). In the high malaria season, anemia prevalence was 41% in malaria-negative children and 54% in malaria-positive children (p < 0.001), with significant malaria-age interactions (p = 0.02 for anemia). Age-stratified prevalence of anemia in malaria positive versus negative children was 67.0% versus 37.1% (in children < 60 months); 57.0% versus 37.2% (in 60-69 months.); 46.8% versus 37.2% (in 70-79 months.); 37.0% versus 37.3% (in 80-89 months) and 28.0% versus 37.4% (in 90+ months).

Conclusions

Malarial anemia is most severe in younger children, especially when transmission is intense. Anemia control programs must prioritize this vulnerable group.

Iron supplementation in anemic Zanzibari toddlers is associated with greater loss in erythrocyte iron isotope enrichment

BACKGROUND

Heavy parasitic loads increase the risk of iron (Fe) deficiency anemia, which remains prevalent globally. Where parasites are common, understanding the influence of parasitic infections on Fe incorporation and erythropoiesis in toddlers is especially important.

OBJECTIVES

The aim of this study was to identify the impacts of malarial and helminth infections on red blood cell (RBC) Fe incorporation and subsequent changes in RBC Fe isotope enrichment for 84 days postdosing in toddlers at high risk for parasitic infections.

METHODS

Fe incorporation was measured in a group of Zanzibari toddlers (n = 71; 16-25 months) using a stable Fe isotopic method. At study entry, an oral stable Fe isotope was administered. Blood was collected 14 (D14) and 84 (D84) days postdosing for the assessment of Fe status indicators and RBC isotopic enrichment. Blood and stool samples were collected and screened for malaria and helminth parasites. Factors associated with changes in RBC Fe isotope enrichment were identified using regression models.

RESULTS

Toddlers who had larger weight-for-age z-scores, lower total body Fe, and helminth infections (n = 26) exhibited higher RBC Fe incorporation. RBC Fe isotope enrichment decreased from D14 to D84 by -2.75 percentage points (P < 0.0001; n = 66). Greater loss in RBC Fe isotope enrichment from D14 to D84 was observed in those who received Fe supplementation, those with either helminths or both malarial and helminth infections, and in those with greater RBC Fe incorporation on D14.

CONCLUSIONS

Toddlers who received Fe supplementation exhibited significantly greater losses of RBC Fe isotope enrichment over time. We speculate this greater loss of RBC Fe enrichment is indicative of increased erythropoiesis due to the provision of Fe among anemic or helminth-infected toddlers.

Plasmodium chabaudi Infection Alters Intestinal Morphology and Mucosal Innate Immunity in Moderately Malnourished Mice

Plasmodium falciparum is a protozoan parasite which causes malarial disease in humans. Infections commonly occur in sub-Saharan Africa, a region with high rates of inadequate nutrient consumption resulting in malnutrition. The complex relationship between malaria and malnutrition and their effects on gut immunity and physiology are poorly understood. Here, we investigated the effect of malaria infection in the guts of moderately malnourished mice. We utilized a well-established low protein diet that is deficient in zinc and iron to induce moderate malnutrition and investigated mucosal tissue phenotype, permeability, and innate immune response in the gut. We observed that the infected moderately malnourished mice had lower parasite burden at the peak of infection, but damaged mucosal epithelial cells and high levels of FITC-Dextran concentration in the blood serum, indicating increased intestinal permeability. The small intestine in the moderately malnourished mice were also shorter after infection with malaria. This was accompanied with lower numbers of CD11b⁺ macrophages, CD11b⁺CD11c⁺ myeloid cells, and CD11c⁺ dendritic cells in large intestine. Despite the lower number of innate immune cells, macrophages in the moderately malnourished mice were highly activated as determined by MHCII expression and increased IFNγ production in the small intestine. Thus, our data suggest that malaria infection may exacerbate some of the abnormalities in the gut induced by moderate malnutrition.

Risk of malaria in young children after periconceptional iron supplementation

This study in Burkina Faso investigated whether offspring of young mothers who had received weekly periconceptional iron supplementation in a randomised controlled trial were at increased risk of malaria. A child safety survey was undertaken in the peak month of malaria transmission towards the end of the trial to assess child iron biomarkers, nutritional status, anaemia and malaria outcomes. Antenatal iron biomarkers, preterm birth, fetal growth restriction and placental pathology for malaria and chorioamnionitis were assessed. Data were available for 180 babies surviving to the time of the survey when their median age was 9 months. Prevalence of maternal iron deficiency in the last trimester based on low body iron stores was 16%. Prevalence of active placental malaria infection was 24.8%, past infection 59% and chorioamnionitis 55.6%. Babies of iron supplemented women had lower median gestational age. Four out of five children ≥ 6 months were iron deficient, and 98% were anaemic. At 4 months malaria prevalence was 45%. Child iron biomarkers, anaemia and malaria outcomes did not differ by trial arm. Factors associated with childhood parasitaemia were third trimester C-reactive protein level (OR 2.1; 95% CI 1.1-3.9), active placental malaria (OR 5.8; 1.0-32.5, P = 0.042) and child body iron stores (OR 1.13; 1.04-1.23, P = 0.002). Chorioamnionitis was associated with reduced risk of child parasitaemia (OR 0.4; 0.1-1.0, P = 0.038). Periconceptional iron supplementation of young women did not alter body iron stores of their children. Higher child body iron stores and placental malaria increased risk of childhood parasitaemia.

Iron Status of Burkinabé Adolescent Girls Predicts Malaria Risk in the Following Rainy Season

High levels of storage iron may increase malaria susceptibility. This risk has not been investigated in semi-immune adolescents. We investigated whether baseline iron status of non-pregnant adolescent girls living in a high malaria transmission area in Burkina Faso affected malaria risk during the following rainy season. For this prospective study, we analysed data from an interim safety survey, conducted six months into a randomised iron supplementation trial. We used logistic regression to model the risk of P. falciparum infection prevalence by microscopy, the pre-specified interim safety outcome, in relation to iron status, nutritional indicators and menarche assessed at recruitment. The interim survey was attended by 1223 (82%) of 1486 eligible participants, 1084 (89%) of whom were <20 years at baseline and 242 (22%) were pre-menarcheal. At baseline, prevalence of low body iron stores was 10%. At follow-up, 38% of adolescents had predominantly asymptomatic malaria parasitaemias, with no difference by menarcheal status. Higher body iron stores at baseline predicted an increased malaria risk in the following rainy season (OR 1.18 (95% CI 1.05, 1.34, p = 0.007) after adjusting for bed net use, age, menarche, and body mass index. We conclude that routine iron supplementation should not be recommended without prior effective malaria control.

Comparison of different doses of daily iron supplementation for anemia prophylaxis in pregnancy: A systematic review

Different doses of iron are used for oral supplementation during pregnancy throughout the world. This objective of this review is to describe the effectiveness and side effect profile of different doses of oral iron supplementation for prophylaxis of anemia among pregnant women. Published literature was searched using keywords "iron," "pregnancy," and "supplementation" and related terms. Gray literature was searched in medical libraries including National Medical Library, Dr. B. B. Dikshit library, and library of ICMR. Intervention studies comparing different doses of oral iron given as prophylaxis for anemia during pregnancy, published till December 2017, were retrieved. Studies done only among anemic patients, and studies comparing oral iron with placebo were excluded. In total, 1588 studies were obtained and 11 of them met the objectives. In global studies, prophylactic dose of 30 mg and above is shown to maintain normal hemoglobin. Among the studies from India, prophylactic dose of 120 mg showed consistent results and 60 mg showed inconsistent results in increasing both hemoglobin and ferritin levels. No significant difference in side effects was reported up to 80 mg iron in global studies and the side effects were comparable with 60 to 240 mg doses in Indian studies. It was evident from the review that a state of clinical equipoise exists for the ideal dose of iron supplementation for the prevention of anemia in pregnancy in terms of efficacy and side effect profile. Robust clinical trial as well as technical consultation is required, especially in Indian setting to explore this question further.

Iron Status and Associated Malaria Risk Among African Children

BACKGROUND

It remains unclear whether improving iron status increases malaria risk, and few studies have looked at the effect of host iron status on subsequent malaria infection. We therefore aimed to determine whether a child's iron status influences their subsequent risk of malaria infection in sub-Saharan Africa.

METHODS

We assayed iron and inflammatory biomarkers from community-based cohorts of 1309 Kenyan and 1374 Ugandan children aged 0-7 years and conducted prospective surveillance for episodes of malaria. Poisson regression models were fitted to determine the effect of iron status on the incidence rate ratio (IRR) of malaria using longitudinal data covering a period of 6 months. Models were adjusted for age, sex, parasitemia, inflammation, and study site.

RESULTS

At baseline, the prevalence of iron deficiency (ID) was 36.9% and 34.6% in Kenyan and Ugandan children, respectively. ID anemia (IDA) affected 23.6% of Kenyan and 17.6% of Ugandan children. Malaria risk was lower in children with ID (IRR, 0.7; 95% confidence interval [CI], 0.6, 0.8; P < .001) and IDA (IRR, 0.7; 95% CI, 0.6, 0.9; P = .006). Low transferrin saturation (<10%) was similarly associated with lower malaria risk (IRR, 0.8; 95% CI, 0.6, 0.9; P = .016). However, variation in hepcidin, soluble transferrin receptors (sTfR), and hemoglobin/anemia was not associated with altered malaria risk.

CONCLUSIONS

ID appears to protect against malaria infection in African children when defined using ferritin and transferrin saturation, but not when defined by hepcidin, sTfR, or hemoglobin. Additional research is required to determine causality.

CLINICAL TRIALS REGISTRATION

ISRCTN32849447.

Malaria causes long-term effects on markers of iron status in children: a critical assessment of existing clinical and epidemiological tools

Background

Most epidemiological studies on the interplay between iron deficiency and malaria risk classify individuals as iron-deficient or iron-replete based on inflammation-dependent iron markers and adjustment for inflammation by using C-reactive protein (CRP) or α-1-acid glycoprotein (AGP). The validity of this approach and the usefulness of fibroblast growth factor 23 (FGF23) as a proposed inflammation-independent iron marker were tested.

Methods

Conventional iron markers and FGF23 were measured in children with acute falciparum malaria and after 1, 2, 4, and 6 weeks. Children, who were transfused or received iron supplementation in the follow-up period, were excluded, and iron stores were considered to be stable throughout. Ferritin levels 6 weeks after admission were used as a reference for admission iron status and compared with iron markers at different time points.

Results

There were long-term perturbations in iron markers during convalescence from acute malaria. None of the tested iron parameters, including FGF23, were independent of inflammation. CRP and AGP normalized faster than ferritin after malaria episodes.

Conclusion

Malaria may bias epidemiological studies based on inflammation-dependent iron markers. Better markers of iron status during and after inflammation are needed in order to test strategies for iron supplementation in populations at risk of malaria.