Imperial College London

Professor Thomas N Williams

Faculty of MedicineDepartment of Surgery & Cancer

Chair in Haemoglobinopathy Research
 
 
 
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Contact

 

tom.williams Website

 
 
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Location

 

Norfolk PlaceSt Mary's Campus

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Summary

 

Publications

Publication Type
Year
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334 results found

Gilchrist JJ, Kariuki S, Watson JA, Band G, Uyoga S, Ndila CM, Mturi N, Mwarumba S, Mohammed S, Mosobo M, Alasoo K, Rockett KA, Mentzer A, Kwiatkowski DP, Hill AVS, Maitland K, Scott JAG, Williams Tet al., 2022, BIRC6 modifies risk of invasive bacterial infection in Kenyan children, eLife, Pages: 1-23, ISSN: 2050-084X

Invasive bacterial disease is a major cause of morbidity and mortality in African children. Despite being caused by diverse pathogens, children with sepsis are clinically indistinguishable from one another. In spite of this, most genetic susceptibility loci for invasive infection that have been discovered to date are pathogen specific and are not therefore suggestive of a shared genetic architecture of bacterial sepsis. Here we utilise probabilistic diagnostic models to identify children with a high probability of invasive bacterial disease among critically unwell Kenyan children with P. falciparum parasitaemia. We construct a joint dataset including 1,445 bacteraemia cases and 1,143 severe malaria cases, and population controls, among critically unwell Kenyan children that have previously been genotyped for human genetic variation. Using these data we perform a cross-trait genome-wide association study of invasive bacterial infection, weighting cases according to their probability of bacterial disease. In doing so we identify and validate a novel risk locus for invasive infection secondary to multiple bacterial pathogens, that has no apparent effect on malaria risk. The locus identified modifies splicing of BIRC6 in stimulated monocytes, implicating regulation of apoptosis and autophagy in the pathogenesis of sepsis in Kenyan children.

Journal article

Watson J, Uyoga S, Wanjiku P, Makale J, Nyutu G, Mturi N, George E, Woodrow C, Day N, Bejon P, Opoka R, Dondorp A, John C, Maitland K, Williams T, White Net al., 2022, Improving the diagnosis of severe malaria in African children using platelet counts and plasma Pf HRP2 concentrations, Science Translational Medicine, Vol: 14, Pages: 1-10, ISSN: 1946-6234

Severe falciparum malaria is difficult to diagnose accurately in children inhigh transmission settings. Using data from 2,649 patients enrolled in fourstudies of severe illness in three countries (Bangladesh, Kenya, and Uganda),we fitted Bayesian latent class models using two diagnostic biomarkers: theplatelet count and the plasma PfHRP2 concentration. In severely ill patientswith clinical features consistent with severe malaria, a combined platelet count≤ 150,000 per µL and a plasma PfHRP2 concentration ≥ 1,000 ng/mL had anestimated sensitivity of 74% and specificity of 93% in identifying ‘true’ severefalciparum malaria. Compared to misdiagnosed children, patients with truesevere malaria had higher parasite densities, lower hematocrits, lower ratesof invasive bacterial disease, and a lower prevalence of both HbAS and HbSS.We estimate one third of African children enrolled in clinical studies of severemalaria in high transmission settings had another cause of severe illness.

Journal article

Musasia FK, Nkumama IN, Frank R, Kipkemboi V, Schneider M, Mwai K, Odera DO, Rosenkranz M, Fürle K, Kimani D, Tuju J, Njuguna P, Hamaluba M, Kapulu MC, Wardemann H, CHMI-SIKA Study Team, Osier FHAet al., 2022, Phagocytosis of Plasmodium falciparum ring-stage parasites predicts protection against malaria., Nat Commun, Vol: 13

Ring-infected erythrocytes are the predominant asexual stage in the peripheral circulation but are rarely investigated in the context of acquired immunity against Plasmodium falciparum malaria. Here we compare antibody-dependent phagocytosis of ring-infected parasite cultures in samples from a controlled human malaria infection (CHMI) study (NCT02739763). Protected volunteers did not develop clinical symptoms, maintained parasitaemia below a predefined threshold of 500 parasites/μl and were not treated until the end of the study. Antibody-dependent phagocytosis of both ring-infected and uninfected erythrocytes from parasite cultures was strongly correlated with protection. A surface proteomic analysis revealed the presence of merozoite proteins including erythrocyte binding antigen-175 and -140 on ring-infected and uninfected erythrocytes, providing an additional antibody-mediated protective mechanism for their activity beyond invasion-inhibition. Competition phagocytosis assays support the hypothesis that merozoite antigens are the key mediators of this functional activity. Targeting ring-stage parasites may contribute to the control of parasitaemia and prevention of clinical malaria.

Journal article

Macharia AW, Mochamah G, Makale J, Howard T, Mturi N, Olupot-Olupot P, Färnert A, Ware RE, Williams TNet al., 2022, Case report: β-thalassemia major on the East African coast, Wellcome Open Research, Vol: 7, Pages: 188-188, ISSN: 2398-502X

Background: β-thalassemia is rare in sub-Saharan Africa and to our knowledge there has been no case of homozygous β-thalassemia major reported from this region. In a recent cohort study, we identified four β-thalassemia mutations among 83 heterozygous carriers in Kilifi, Kenya. One of the mutations identified was a rare β-globin gene initiation codon mutation (ATG➝ACG) (rs33941849). Here we present a patient with β-thalassemia major resulting from this mutation, only the second homozygous patient to have been reported. Methods: The female patient presented to Kilifi County Hospital aged two years with a one week left sided abdominal swelling. Clinical, hematological and genetic information were collected at admission and follow-up. Results: Admission bloods revealed marked anemia, with a hemoglobin (Hb) value of 6.6 g/dL and a low mean corpuscular volume of 64 fL. High performance liquid chromatography (HPLC) revealed the absence of HbA0 and elevated levels of HbF, suggesting a diagnosis of β-thalassemia major. Sequencing revealed that the child was homozygous for the rs33941849 initiation codon mutation. Conclusions: We hope that this study will create awareness regarding the presence of β-thalassemia as a potential public health problem in the East Africa region and will prompt the development of local guidelines regarding the diagnosis and management of this condition.

Journal article

Abuga K, Muriuki J, Uyoga S, Mwai K, Makale J, Mogire R, Macharia A, Mohammed S, Muthumbi E, Mwarumba S, Mturi N, Bejon P, Scott A, Nairz M, Williams T, Atkinson Set al., 2022, Hepcidin regulation in Kenyan children with severe malaria and non-typhoidal Salmonella bacteremia, Haematologica: the hematology journal, Vol: 107, Pages: 1589-1598, ISSN: 0390-6078

Malaria and invasive non-typhoidal Salmonella (NTS) are life-threatening infections that often co-exist in African children. The iron-regulatory hormone hepcidin is highly upregulated during malaria and controls the availability of iron, a critical nutrient for bacterial growth. We investigated the relationship between Plasmodium falciparum malaria and NTS bacteremia in all pediatric admissions aged ≤5 years between August 1998 and October 2019 (n=75,034). We then assayed hepcidin and measures of iron status in five groups: (1) children with concomitant severe malarial anemia (SMA) and NTS (SMA+NTS, n=16); and in matched children with (2) SMA (n=33); (3) NTS (n=33); (4) cerebral malaria (CM, n=34); and (5) community-based children. SMA and severe anemia without malaria were associated with a two-fold or more increased risk of NTS bacteremia, while other malaria phenotypes were not associated with increased NTS risk. Children with SMA had lower hepcidin/ferritin ratios (0.10 [IQR 0.03, 0.19]) than those with CM (0.24 [0.14, 0.69]; P=0.006) or asymptomatic malaria (0.19 [0.09, 0.46]; P=0.01) indicating suppressed hepcidin levels. Children with SMA+NTS had lower hepcidin levels (9.3 ng/mL [4.7, 49.8]) and hepcidin/ferritin ratios (0.03 [0.01, 0.22]) than those with NTS alone (105.8 ng/mL [17.3, 233.3]; P=0.02 and 0.31 [0.06, 0.66]; P=0.007, respectively). Since hepcidin degrades ferroportin on the Salmonella-containing vacuole (SCV), we hypothesize that reduced hepcidin in children with SMA might contribute to NTS growth by modulating iron availability for bacterial growth. Further studies are needed to understand how the hepcidin-ferroportin axis might mediate susceptibility to NTS in severely anemic children.

Journal article

Uyoga S, Watson J, Wanjiku P, Rop J, Makale J, Macharia A, Kariuki S, Nyutu G, Shebe M, Mosobo M, Mturi N, Rockett K, Woodrow C, Dondorp A, Maitland K, White N, Williams Tet al., 2022, The impact of malaria-protective red blood cell polymorphisms on parasite biomass in children with severe Plasmodium falciparum malaria, Nature Communications, Vol: 13, Pages: 1-7, ISSN: 2041-1723

Severe falciparum malaria is a major cause of preventable child mortality in sub-Saharan Africa. Plasma concentrations of P. falciparum Histidine-Rich Protein 2 (PfHRP2) have diagnostic and prognostic value in severe malaria. We investigate the potential use of plasma PfHRP2 and the sequestration index (the ratio of PfHRP2 to parasite density) as quantitative traits for case-only genetic association studies of severe malaria. Data from 2198 Kenyan children diagnosed with severe malaria, genotyped for 14 major candidate genes, show that polymorphisms in four major red cell genes that lead to hemoglobin S, O blood group, α-thalassemia, and the Dantu blood group, are associated with substantially lower admission plasma PfHRP2 concentrations, consistent with protective effects against extensive parasitized erythrocyte sequestration. In contrast the known protective ATP2B4 polymorphism is associated with higher plasma PfHRP2 concentrations, lower parasite densities and a higher sequestration index. We provide testable hypotheses for the mechanism of protection of ATP2B4.

Journal article

Nardo-Marino A, Petersen J, Brewin J, Birgens H, Williams T, Kurtzhals J, Rees D, Glenthøj Aet al., 2022, Oxygen gradient ektacytometry does not predict pain in children with sickle cell anaemia, British Journal of Haematology, Vol: 197, Pages: 609-617, ISSN: 0007-1048

The loss of red blood cell (RBC) deformability in sickle cell anaemia (SCA) is considered the primary factor responsible for episodes of acute pain and downstream progressive organ dysfunction. Oxygen gradient ektacytometry (Oxygenscan) is a recently commercialised functional assay that aims to describe the deformability of RBCs in SCA at differing oxygen tensions. So far, the Oxygenscan has been evaluated only by a small number of research groups and the validity and clinical value of Oxygenscan-derived biomarkers have not yet been fully established. In this study we examined RBC deformability measured with the Oxygenscan in 91 children with SCA at King’s College Hospital in London. We found a significant correlation between Oxygenscan-derived biomarkers and well-recognised modifiers of disease severity in SCA: haemoglobin F and co-inherited α-thalassaemia. We failed, however, to find any independent predictive value of the Oxygenscan in the clinical outcome measure of pain, as well as other important parameters such as hydroxycarbamide treatment. Although the Oxygenscan remains an intriguing tool for basic research, our results question whether it provides any additional information in predicting the clinical course in children with SCA, beyond measuring known markers of disease severity.

Journal article

Olupot-Olupot P, Connon R, Kiguli S, Opoka RO, Alaroker F, Uyoga S, Nakuya M, Okiror W, Nteziyaremye J, Ssenyondo T, Nabawanuka E, Kayaga J, Williams Mukisa C, Amorut D, Muhindo R, Frost G, Walsh K, Macharia AW, Gibb DM, Walker AS, George EC, Maitland K, Williams TN, Williams Tet al., 2022, A predictive algorithm for identifying children with sickle cell anemia among children admitted to hospital with severe anemia in Africa, American Journal of Hematology, Vol: 97, Pages: 527-536, ISSN: 0361-8609

Sickle cell anemia (SCA) is common in sub-Saharan Africa where approximately 1% of births are affected. Severe anemia is a common cause for hospital admission within the region yet few studies have investigated the contribution made by SCA. The Transfusion and Treatment of severe anemia in African Children Trial (ISRCTN84086586) investigated various treatment strategies in 3983 children admitted with severe anemia (hemoglobin < 6.0 g/dl) based on two severity strata to four hospitals in Africa (three Uganda and one Malawi). Children with known-SCA were excluded from the uncomplicated stratum and capped at 25% in the complicated stratum. All participants were genotyped for SCA at trial completion. SCA was rare in Malawi (six patients overall), so here we focus on the participants recruited in Uganda. We present baseline characteristics by SCA status and propose an algorithm for identifying children with unknown-SCA. Overall, 430 (12%) and 608 (17%) of the 3483 Ugandan participants had known- or unknown-SCA, respectively. Children with SCA were less likely to be malaria-positive and more likely to have an affected sibling, have gross splenomegaly, or to have received a previous blood transfusion. Most outcomes, including mortality and readmission, were better in children with either known or unknown-SCA than non-SCA children. A simple algorithm based on seven admission criteria detected 73% of all children with unknown-SCA with a number needed to test to identify one new SCA case of only two. Our proposed algorithm offers an efficient and cost-effective approach to identifying children with unknown-SCA among all children admitted with severe anemia to African hospitals where screening is not widely available.

Journal article

Uyoga S, Olupot-Olupot P, Connon R, Kiguli S, Opoka R, Alaroker F, Muhindo R, Macharia AW, Dondorp A, Gibb D, Walker AS, George E, Maitland K, Williams Tet al., 2022, Sickle cell anaemia and severe P. falciparum malaria: a secondary analysis of the Transfusion and Treatment of African Children (TRACT) trial, The Lancet Child & Adolescent Health, ISSN: 2352-4642

BackgroundSickle cell anaemia (SCA; HbSS) has historically been associated with high levels of childhood mortality in Africa. While malaria plays a major contribution to this mortality to date, the clinical pathology of malaria among children with SCA has been poorly described. Methods We investigated the burden and severity of malaria infections among children recruited with severe anaemia to the TRACT trial of blood transfusion in Africa. This secondary analysis, conducted after trial completion, is restricted to Uganda, where the birth prevalence of SCA is approximately 1% and malaria transmission is high. Children were classified as normal (HbAA), heterozygous (HbAS) or homozygous (HbSS; SCA) for the rs334 A>T sickle mutation in HBB following batch-genotyping by PCR at the end of trial. To avoid confounding from SCA-specific medical interventions, we considered children with an existing diagnosis of SCA (known-SCA) separately from those diagnosed at the end of the trial (unknown-SCA). Findings Overall, 1,038 of 3,483 (30%) of the Ugandan children recruited to TRACT had SCA. While 1,815/2,321 (78%) of the non-SCA (HbAA) children tested positive for P. falciparum malaria, the prevalence was significantly lower in children with SCA (347/1,038; 33%; p<0.001). Concentrations of plasma P. falciparum Histidine Rich Protein 2 (PfHRP2), a marker of the total burden of malaria parasites within an individual, were significantly lower in children with either known-SCA (median 8 ng/mL; IQR 0-57) or unknown-SCA (7 ng/mL (0-50 ng/mL) than in HbAA children (346 ng/mL; 21-2,121; p<0.001). By contrast to HbAA children, few HbSS children presented with classic features of severe and complicated malaria, but both the frequency and severity of anaemia were higher in HbSS children.Interpretation The current study suggests that children with SCA are innately protected against classic severe malaria. However, it also shows that even low-level infections can precipitate severe

Journal article

Nardo-Marino A, Braunstein TH, Petersen J, Brewin JN, Mottelson MN, Williams TN, Kurtzhals JAL, Rees DC, Glenthøj Aet al., 2022, Automating pitted red blood cell counts using deep neural network analysis: a new method for measuring splenic function in sickle cell anaemia, Frontiers in Physiology, Vol: 13, ISSN: 1664-042X

The spleen plays an important role in the body's defence against bacterial infections. Measuring splenic function is of interest in multiple conditions, including sickle cell anaemia (SCA), where spleen injury occurs early in life. Unfortunately, there is no direct and simple way of measuring splenic function, and it is rarely assessed in clinical or research settings. Manual counts of pitted red blood cells (RBCs) observed with differential interference contrast (DIC) microscopy is a well-validated surrogate biomarker of splenic function. The method, however, is both user-dependent and laborious. In this study, we propose a new automated workflow for counting pitted RBCs using deep neural network analysis. Secondly, we assess the durability of fixed RBCs for pitted RBC counts over time. We included samples from 48 children with SCA and 10 healthy controls. Cells were fixed in paraformaldehyde and examined using an oil-immersion objective, and microscopy images were recorded with a DIC setup. Manual pitted RBC counts were performed by examining a minimum of 500 RBCs for pits, expressing the proportion of pitted RBCs as a percentage (%PIT). Automated pitted RBC counts were generated by first segmenting DIC images using a Zeiss Intellesis deep learning model, recognising and segmenting cells and pits from background. Subsequently, segmented images were analysed using a small ImageJ macro language script. Selected samples were stored for 24 months, and manual pitted RBC counts performed at various time points. When comparing manual and automated pitted RBC counts, we found the two methods to yield comparable results. Although variability between the measurements increased with higher %PIT, this did not change the diagnosis of asplenia. Furthermore, we found no significant changes in %PIT after storing samples for up to 24 months and under varying temperatures and light exposures. We have shown that automated pitted RBC counts, produced using deep neural

Journal article

Mogire RM, Muriuki JM, Morovat A, Mentzer AJ, Webb EL, Kimita W, Ndungu FM, Macharia AW, Cutland CL, Sirima SB, Diarra A, Tiono AB, Lule SA, Madhi SA, Prentice AM, Bejon P, Pettifor JM, Elliott AM, Adeyemo A, Williams T, Atkinson SHet al., 2022, Vitamin D deficiency and its association with iron deficiency in African children, Nutrients, Vol: 14, ISSN: 2072-6643

Vitamin D regulates the master iron hormone hepcidin, and iron in turn alters vitamin D me-tabolism. Although vitamin D and iron deficiency are highly prevalent globally little is known about their interactions in Africa. To evaluate associations between vitamin D and iron status we measured markers of iron status, inflammation, malaria parasitemia and 25-hydroxyvitamin D (25(OH)D) concentrations in 4509 children aged 0.3 months to 8 years living in Kenya, Uganda, Burkina Faso, The Gambia and South Africa. Prevalence of iron deficiency was 35.1%, and preva-lence of vitamin D deficiency was 0.6% and 7.8% as defined by 25(OH)D concentrations of <30 nmol/L and <50 nmol/L respectively. Children with 25(OH)D concentrations of <50 nmol/L had a 98% increased risk of iron deficiency (OR 1.98 [95% CI 1.52, 2.58]) compared to those with 25(OH)D concentrations >75 nmol/L. 25(OH)D concentrations variably influenced individual markers of iron status. Inflammation interacted with 25(OH)D concentrations to predict ferritin levels. The link between vitamin D and iron status should be considered in strategies to manage these nutrient deficiencies in African children.

Journal article

George EC, Uyoga S, M'baya B, Byabazair DK, Kiguli S, Olupot-Olupot P, Opoka RO, Chagaluka G, Alaroker F, Williams TN, Bates I, Mbanya D, Gibb DM, Walker AS, Maitland K, TRACT trail study groupet al., 2022, Whole blood versus red cell concentrates for children with severe anaemia: a secondary analysis of the Transfusion and Treatment of African Children (TRACT) trial, The Lancet Global Health, Vol: 10, Pages: e360-e368, ISSN: 2214-109X

Background:The multicentre Transfusion and Treatment of African Children (TRACT) trial established best evidence on the timing of transfusion in children with uncomplicated anaemia (haemoglobin 4-6g/dl) and optimal volume (20 versus 30ml/kg whole blood (or 10 vs 15ml/kg red cell concentrates) for transfusion in children hospitalised with severe anaemia (Hb <6g/dl) on Day 28 mortality (primary endpoint) and secondary endpoints including safety. As evidence on the safety of blood components is limited we undertook a secondary analysis comparing children receiving whole blood versus red cell concentrates as their initial transfusion on clinical outcomes. Methods :This analysis includes 3188 children with severe anaemia (Hb <6g/dl) who received either whole blood or red cell concentrates. Whole blood or cell concentrates were issued routinely by the blood transfusion services, but not prespecified on the request form. The impact of blood pack type on haematological correction, re-transfusion, and other clinical endpoints was explored using multivariate regression models. Findings:1632/3992 (41%) transfusions in 3188 children were whole blood. Compared with whole blood, children receiving cell concentrates in their first transfusion had less haemoglobin recovery at 8 hours (packed cells mean(95%CI): -1.3(-1.5,-1.0) 20ml/kg arm,-1.4(-1.6,-1.1) 30ml/kg; settled cells mean(95%CI) -1.1g/dl(-1.2,-0.9) 20ml/kg arm, -1.5g/dl(-1.7,-1.3) 30ml/kg arm; p<0.001 for pack type comparisons, p=0.003 heterogeneity by arm), higher odds of receiving a second transfusion [ORs 2.32 (95%CI 1.30,4.12) and 2.97 (2.18,4.05) respectively; p<0.001], and had a longer time to discharge [sub-Hazard Ratios 0.94 (95%CI 0.81,1.10) and 0.86 (95% CI 0.79,0.94) respectively; p=0.002]. No child developed features of cardio-pulmonary overload. Interpretation: Whole blood is safe to use in children, resulting in superior aematologic

Journal article

Williams TN, 2022, Filling the data gaps on sickle cell anaemia in sub-Saharan Africa, The Lancet Haematology, Vol: 9, Pages: e172-e173, ISSN: 2352-3026

Journal article

Kapulu MC, Kimani D, Njuguna P, Hamaluba M, Otieno E, Kimathi R, Tuju J, Sim BKL, CHMI-SIKA Study Teamet al., 2022, Controlled human malaria infection (CHMI) outcomes in Kenyan adults is associated with prior history of malaria exposure and anti-schizont antibody response, BMC Infect Dis, Vol: 22

BACKGROUND: Individuals living in endemic areas acquire immunity to malaria following repeated parasite exposure. We sought to assess the controlled human malaria infection (CHMI) model as a means of studying naturally acquired immunity in Kenyan adults with varying malaria exposure. METHODS: We analysed data from 142 Kenyan adults from three locations representing distinct areas of malaria endemicity (Ahero, Kilifi North and Kilifi South) enrolled in a CHMI study with Plasmodium falciparum sporozoites NF54 strain (Sanaria® PfSPZ Challenge). To identify the in vivo outcomes that most closely reflected naturally acquired immunity, parameters based on qPCR measurements were compared with anti-schizont antibody levels and residence as proxy markers of naturally acquired immunity. RESULTS: Time to endpoint correlated more closely with anti-schizont antibodies and location of residence than other parasite parameters such as growth rate or mean parasite density. Compared to observational field-based studies in children where 0.8% of the variability in malaria outcome was observed to be explained by anti-schizont antibodies, in the CHMI model the dichotomized anti-schizont antibodies explained 17% of the variability. CONCLUSIONS: The CHMI model is highly effective in studying markers of naturally acquired immunity to malaria. Trial registration Clinicaltrials.gov number NCT02739763. Registered 15 April 2016.

Journal article

Wirth JP, Sesay F, Mbai J, Ali SI, Donkor WES, Woodruff BA, Pilane Z, Mohamud KM, Muse A, Yussuf HO, Mohamed WS, Veraguth R, Rezzi S, Williams TN, Mohamoud AM, Mohamud FM, Galvin M, Rohner F, Katambo Y, Petry Net al., 2022, Risk factors of anaemia and iron deficiency in Somali children and women: Findings from the 2019 Somalia Micronutrient Survey, Maternal and Child Nutrition, Vol: 18, ISSN: 1740-8695

There are limited data on the prevalence of anaemia and iron deficiency (ID) in Somalia. To address this data gap, Somalia's 2019 micronutrient survey assessed the prevalence of anaemia and ID in children (6-59 months) and non-pregnant women of reproductive age (15-49 years). The survey also collected data on vitamin A deficiency, inflammation, malaria and other potential risk factors for anaemia and ID. Multivariable Poisson regressions models were used to identify the risk factors for anaemia and ID in children and women. Among children, the prevalence of anaemia and ID were 43.4% and 47.2%, respectively. Approximately 36% and 6% of anaemia were attributable to iron and vitamin A deficiencies, respectively, whereas household possession of soap was associated with approximately 11% fewer cases of anaemia. ID in children was associated with vitamin A deficiency and stunting, whereas inflammation was associated with iron sufficiency. Among women, 40.3% were anaemic, and 49.7% were iron deficient. In women, ID and number of births were significantly associated with anaemia in multivariate models, and approximately 42% of anaemia in women was attributable to ID. Increased parity was associated with ID, and incubation and early convalescent inflammation was associated with ID, whereas late convalescent inflammation was associated with iron sufficiency. ID is the main risk factor of anaemia in both women and children and contributed to a substantial portion of the anaemia cases. To tackle both anaemia and ID in Somalia, food assistance and micronutrient-specific programmes (e.g. micronutrient powders and iron supplements) should be enhanced.

Journal article

Band G, Leffler EM, Jallow M, Sisay-Joof F, Ndila CM, Macharia AW, Hubbart C, Jeffreys AE, Rowlands K, Nguyen T, Gonçalves S, Ariani CV, Stalker J, Pearson RD, Amato R, Drury E, Sirugo G, d'Alessandro U, Bojang KA, Marsh K, Peshu N, Saelens JW, Diakité M, Taylor SM, Conway DJ, Williams TN, Rockett KA, Kwiatkowski DPet al., 2021, Malaria protection due to sickle haemoglobin depends on parasite genotype, Nature, Vol: 602, Pages: 1-23, ISSN: 0028-0836

Host genetic factors can confer resistance against malaria1, raising the question of whether this has led to evolutionary adaptation of parasite populations. Here we searched for association between candidate host and parasite genetic variants in 3,346 Gambian and Kenyan children with severe malaria caused by Plasmodium falciparum. We identified a strong association between sickle haemoglobin (HbS) in the host and three regions of the parasite genome, which is not explained by population structure or other covariates, and which is replicated in additional samples. The HbS-associated alleles include nonsynonymous variants in the gene for the acyl-CoA synthetase family member2-4 PfACS8 on chromosome 2, in a second region of chromosome 2, and in a region containing structural variation on chromosome 11. The alleles are in strong linkage disequilibrium and have frequencies that covary with the frequency of HbS across populations, in particular being much more common in Africa than other parts of the world. The estimated protective effect of HbS against severe malaria, as determined by comparison of cases with population controls, varies greatly according to the parasite genotype at these three loci. These findings open up a new avenue of enquiry into the biological and epidemiological significance of the HbS-associated polymorphisms in the parasite genome and the evolutionary forces that have led to their high frequency and strong linkage disequilibrium in African P. falciparum populations.

Journal article

Otiende M, Bauni E, Nyaguara A, Amadi D, Nyundo C, Tsory E, Walumbe D, Kinuthia M, Kihuha N, Kahindi M, Nyutu G, Moisi J, Deribew A, Agweyu A, Marsh K, Tsofa B, Bejon P, Bottomley C, Williams TN, Scott JAGet al., 2021, Mortality in rural coastal Kenya measured using the Kilifi Health and Demographic Surveillance System: a 16-year descriptive analysis, Wellcome Open Research, Vol: 6, Pages: 327-327

<ns4:p><ns4:bold>Background:</ns4:bold> The Kilifi Health and Demographic Surveillance System (KHDSS) was established in 2000 to define the incidence and prevalence of local diseases and evaluate the impact of community-based interventions. KHDSS morbidity data have been reported comprehensively but mortality has not been described. This analysis describes mortality in the KHDSS over 16 years.</ns4:p><ns4:p> <ns4:bold>Methods: </ns4:bold>We calculated mortality rates from 2003–2018 in four intervals of equal duration and assessed differences in mortality across these intervals by age and sex. We calculated the period survival function and median survival using the Kaplan–Meier method and mean life expectancies using abridged life tables. We estimated trend and seasonality by decomposing a time series of monthly mortality rates. We used choropleth maps and random-effects Poisson regression to investigate geographical heterogeneity.</ns4:p><ns4:p> <ns4:bold>Results: </ns4:bold>Mortality declined by 36% overall between 2003–2018 and by 59% in children aged &lt;5 years. Most of the decline occurred between 2003 and 2006. Among adults, the greatest decline (49%) was observed in those aged 15–54 years. Life expectancy at birth increased by 12 years. Females outlived males by 6 years. Seasonality was only evident in the 1–4 year age group in the first four years. Geographical variation in mortality was ±10% of the median value and did not change over time.<ns4:bold> </ns4:bold></ns4:p><ns4:p> <ns4:bold>Conclusions: </ns4:bold>Between 2003 and 2018, mortality among children and young adults has improved substantially. The steep decline in 2003–2006 followed by a much slower reduction thereafter suggests improvements in health and wellbeing have plateaued in the last 12 years. However, there is substantial inequality in mortalit

Journal article

Kiguli S, Olopot-Olupot P, Alaroker F, Engoru C, Opoka R, Tagoola A, Hamaluba M, Mnjalla H, Mpoya A, Mogaka C, Nalwanga D, Nabawanuka E, Nokes J, Nyaigoti C, Briend A, van Woensel J, Grieve R, Sadique Z, Williams T, Thomas K, Harrison D, Rowan K, Maitland Ket al., 2021, Children’s Oxygen Administration Strategies And Nutrition Trial (COAST-Nutrition): a protocol for a phase II randomised controlled trial, Wellcome Open Research, Vol: 6, Pages: 1-23, ISSN: 2398-502X

Background: To prevent poor long-term outcomes (deaths and readmissions) the integrated global action plan for pneumonia and diarrhoea recommends under the ‘Treat’ element of Protect, Prevent and Treat interventions the importance of continued feeding but gives no specific recommendations for nutritional support. Early nutritional support has been practiced in a wide variety of critically ill patients to provide vital cell substrates, antioxidants, vitamins, and minerals essential for normal cell function and decreasing hypermetabolism. We hypothesise that the excess post-discharge mortality associated with pneumonia may relate to the catabolic response and muscle wasting induced by severe infection and inadequacy of the diet to aid recovery. We suggest that providing additional energy-rich, protein, fat and micronutrient ready-to-use therapeutic feeds (RUTF) to help meet additional nutritional requirements may improve outcome.Methods: COAST-Nutrition is an open, multicentre, Phase II randomised controlled trial in children aged 6 months to 12 years hospitalised with suspected severe pneumonia (and hypoxaemia, SpO2 <92%) to establish whether supplementary feeds with RUTF given in addition to usual diet for 56-days (experimental) improves outcomes at 90-days compared to usual diet alone (control). Primary endpoint is change in mid-upper arm circumference (MUAC) at 90 days and/or as a composite with 90-day mortality. Secondary outcomes include anthropometric status, mortality, readmission at days 28 and 180. The trial will be conducted in four sites in two countries (Uganda and Kenya) enrolling 840 children followed up to 180 days. Ancillary studies include cost-economic analysis, molecular characterisation of bacterial and viral pathogens, evaluation of putative biomarkers of pneumonia, assessment of muscle and fat mass and host genetic studies. Discussion: This study is the first step in providing an option for nutritional support following severe pn

Journal article

Kiguli S, Olopot-Olupot P, Alaroker F, Engoru C, Opoka RO, Tagoola A, Hamaluba M, Mnjalla H, Mpoya A, Mogaka C, Nalwanga D, Nabawanuka E, Nokes J, Nyaigoti C, Briend A, van Woensel JBM, Grieve R, Sadique Z, Williams TN, Thomas K, Harrison DA, Rowan K, Maitland Ket al., 2021, Children's Oxygen Administration Strategies And Nutrition Trial (COAST-Nutrition): a protocol for a phase II randomised controlled trial., Wellcome Open Res, Vol: 6, Pages: 221-221, ISSN: 2398-502X

Background: To prevent poor long-term outcomes (deaths and readmissions) the integrated global action plan for pneumonia and diarrhoea recommends under the 'Treat' element of Protect, Prevent and Treat interventions the importance of continued feeding but gives no specific recommendations for nutritional support. Early nutritional support has been practiced in a wide variety of critically ill patients to provide vital cell substrates, antioxidants, vitamins, and minerals essential for normal cell function and decreasing hypermetabolism. We hypothesise that the excess post-discharge mortality associated with pneumonia may relate to the catabolic response and muscle wasting induced by severe infection and inadequacy of the diet to aid recovery. We suggest that providing additional energy-rich, protein, fat and micronutrient ready-to-use therapeutic feeds (RUTF) to help meet additional nutritional requirements may improve outcome. Methods: COAST-Nutrition is an open, multicentre, Phase II randomised controlled trial in children aged 6 months to 12 years hospitalised with suspected severe pneumonia (and hypoxaemia, SpO 2 <92%) to establish whether supplementary feeds with RUTF given in addition to usual diet for 56-days (experimental) improves outcomes at 90-days compared to usual diet alone (control). Primary endpoint is change in mid-upper arm circumference (MUAC) at 90 days and/or as a composite with 90-day mortality. Secondary outcomes include anthropometric status, mortality, readmission at days 28 and 180. The trial will be conducted in four sites in two countries (Uganda and Kenya) enrolling 840 children followed up to 180 days. Ancillary studies include cost-economic analysis, molecular characterisation of bacterial and viral pathogens, evaluation of putative biomarkers of pneumonia, assessment of muscle and fat mass and host genetic studies.   Discussion: This study is the first step in providing an option for nutritional support following severe p

Journal article

Connon R, George EC, Olupot-Olupot P, Kiguli S, Chagaluka G, Alaroker F, Opoka RO, Mpoya A, Walsh K, Engoru C, Nteziyaremye J, Mallewa M, Kennedy N, Nakuya M, Namayanja C, Nabawanuka E, Sennyondo T, Amorut D, Williams Musika C, Bates I, Boele van Hensbroek M, Evans JA, Uyoga S, Williams TN, Frost G, Gibb DM, Maitland K, Walker AS, TRACT trial groupet al., 2021, Incidence and predictors of hospital readmission in children presenting with severe anaemia in Uganda and Malawi: a secondary analysis of TRACT trial data, BMC Public Health, Vol: 21, ISSN: 1471-2458

BACKGROUND: Severe anaemia (haemoglobin < 6 g/dL) is a leading cause of recurrent hospitalisation in African children. We investigated predictors of readmission in children hospitalised with severe anaemia in the TRACT trial (ISRCTN84086586) in order to identify potential future interventions. METHODS: Secondary analyses of the trial examined 3894 children from Uganda and Malawi surviving a hospital episode of severe anaemia. Predictors of all-cause readmission within 180 days of discharge were identified using multivariable regression with death as a competing risk. Groups of children with similar characteristics were identified using hierarchical clustering. RESULTS: Of the 3894 survivors 682 (18%) were readmitted; 403 (10%) had ≥2 re-admissions over 180 days. Three main causes of readmission were identified: severe anaemia (n = 456), malaria (n = 252) and haemoglobinuria/dark urine syndrome (n = 165). Overall, factors increasing risk of readmission included HIV-infection (hazard ratio 2.48 (95% CI 1.63-3.78), p < 0.001); ≥2 hospital admissions in the preceding 12 months (1.44(1.19-1.74), p < 0.001); history of transfusion (1.48(1.13-1.93), p = 0.005); and missing ≥1 trial medication dose (proxy for care quality) (1.43 (1.21-1.69), p < 0.001). Children with uncomplicated severe anaemia (Hb 4-6 g/dL and no severity features), who never received a transfusion (per trial protocol) during the initial admission had a substantially lower risk of readmission (0.67(0.47-0.96), p = 0.04). Malaria (among children with no prior history of transfusion) (0.60(0.47-0.76), p < 0.001); younger-age (1.07 (1.03-1.10) per 1 year younger, p < 0.001) and known sickle cell disease (0.62(0.46-0.82), p = 0.001) also decreased risk of readmission. For anaemia re-admissions, gross

Journal article

Chi PC, Owino EA, Jao I, Olewe F, Ogutu B, Bejon P, Kapulu M, Kamuya D, Marsh V, CHMI-SIKA Study Teamet al., 2021, Understanding the benefits and burdens associated with a malaria human infection study in Kenya: experiences of study volunteers and other stakeholders., Trials, Vol: 22, ISSN: 1745-6215

BACKGROUND: Human infection studies (HIS) that involve deliberately infecting healthy volunteers with a pathogen raise important ethical issues, including the need to ensure that benefits and burdens are understood and appropriately accounted for. Building on earlier work, we embedded social science research within an ongoing malaria human infection study in coastal Kenya to understand the study benefits and burdens experienced by study stakeholders in this low-resource setting and assess the wider implications for future research planning and policy. METHODS: Data were collected using qualitative research methods, including in-depth interviews (44), focus group discussions (10) and non-participation observation. Study participants were purposively selected (key informant or maximal diversity sampling), including volunteers in the human infection study, study staff, community representatives and local administrative authorities. Data were collected during and up to 18 months following study residency, from sites in Coastal and Western Kenya. Voice recordings of interviews and discussions were transcribed, translated, and analysed using framework analysis, combining data- and theory-driven perspectives. FINDINGS: Physical, psychological, economic and social forms of benefits and burdens were experienced across study stages. Important benefits for volunteers included the study compensation, access to health checks, good residential living conditions, new learning opportunities, developing friendships and satisfaction at contributing towards a new malaria vaccine. Burdens primarily affected study volunteers, including experiences of discomfort and ill health; fear and anxiety around aspects of the trial process, particularly deliberate infection and the implications of prolonged residency; anxieties about early residency exit; and interpersonal conflict. These issues had important implications for volunteers' families, study staff and the research institution's reputat

Journal article

Watson JA, Ndila CM, Uyoga S, Macharia A, Nyutu G, Mohammed S, Ngetsa C, Mturi N, Peshu N, Tsofa B, Rockett K, Leopold S, Kingston H, George EC, Maitland K, Day NP, Dondorp AM, Bejon P, Williams T, Holmes CC, White NJet al., 2021, Improving statistical power in severe malaria genetic association studies by augmenting phenotypic precision., eLife, Vol: 10, Pages: 1-39, ISSN: 2050-084X

Severe falciparum malaria has substantially affected human evolution. Genetic association studies of patients with clinically defined severe malaria and matched population controls have helped characterise human genetic susceptibility to severe malaria, but phenotypic imprecision compromises discovered associations. In areas of high malaria transmission the diagnosis of severe malaria in young children and, in particular, the distinction from bacterial sepsis, is imprecise. We developed a probabilistic diagnostic model of severe malaria using platelet and white count data. Under this model we re-analysed clinical and genetic data from 2,220 Kenyan children with clinically defined severe malaria and 3,940 population controls, adjusting for phenotype mis-labelling. Our model, validated by the distribution of sickle trait, estimated that approximately one third of cases did not have severe malaria. We propose a data-tilting approach for case-control studies with phenotype mis-labelling and show that this reduces false discovery rates and improves statistical power in genome-wide association studies.

Journal article

Bundi CK, Nalwoga A, Lubyayi L, Muriuki JM, Mogire RM, Opi H, Mentzer AJ, Mugyenyi CK, Mwacharo J, Webb EL, Bejon P, Williams T, Gikunju JK, Beeson JG, Elliott AM, Ndungu FM, Atkinson SHet al., 2021, Iron deficiency is associated with reduced levels of Plasmodium falciparum-specific antibodies in African children, Clinical Infectious Diseases, Vol: 73, Pages: 43-49, ISSN: 1058-4838

BackgroundIron deficiency (ID) and malaria are common causes of ill-health and disability among children living in sub-Saharan Africa. Although iron is critical for the acquisition of humoral immunity, little is known about the effects of ID on antibody responses to Plasmodium falciparum malaria.MethodsThe study included 1,794 Kenyan and Ugandan children aged 0-7 years. We measured biomarkers of iron and inflammation, and antibodies to P falciparum antigens including apical merozoite antigen 1 (anti-AMA-1) and merozoite surface antigen 1 (anti-MSP-1) in cross-sectional and longitudinal studies.ResultsThe overall prevalence of ID was 31%. ID was associated with lower anti-AMA-1 and anti-MSP-1 antibody levels in pooled analyses adjusted for age, gender, study site, inflammation and P falciparum parasitemia (adjusted mean difference on a log-transformed scale (β) -0.46; 95 CI -0.66, -0.25 P <0.0001; β -0.33; 95 CI -0.50, -0.16 P <0.0001, respectively). Additional covariates for malaria exposure index, previous malaria episodes, and time since last malaria episode, were available for individual cohorts. Meta-analysis was used to allow for these adjustments giving β -0.34; -0.52, -0.16 for anti-AMA-1 antibodies and β -0.26; -0.41, -0.11 for anti-MSP-1 antibodies. Low transferrin saturation was similarly associated with reduced anti-AMA1 antibody levels. Lower AMA-1 and MSP-1 specific antibody levels persisted over time in iron-deficient children.ConclusionsReduced levels of P. falciparum-specific antibodies in iron-deficient children might reflect impaired acquisition of immunity to malaria and/or reduced malaria exposure. Strategies to prevent and treat ID may influence antibody responses to malaria for children living in sub-Saharan Africa.

Journal article

Maitland K, Kiguli S, Olupot-Olupot P, Opoka RO, Chimalizeni Y, Alaroker F, Uyoga S, Kyeyune Byabazaire D, Mbaya B, Bates I, Williams TN, Mbanya D, Munube D, Molyneux EM, South A, Walker AS, Gibb DM, George EMet al., 2021, Transfusion management of severe anaemia in African children: a consensus algorithm, British Journal of Haematology, Vol: 193, Pages: 1247-1259, ISSN: 0007-1048

The phase III Transfusion and Treatment of severe anaemia in African Children Trial(TRACT) found that conservative management of uncomplicated severe anaemia (haemoglobin(Hb)4-6g/dl) was safe and that transfusion volume(20 versus30 mls/kg whole blood equivalent)for children with severe anaemia (Hb<6g/dl) had strong but opposing effects on mortality, depending on fever status (>37.5oC). In 2020 a stakeholder meeting of paediatric and blood transfusion groups from Africa reviewed the results and additional analyses. Among all children (3196) receiving an initial transfusion, there was no evidence that nutritional status, presence of shock, malaria parasite burden, or sickle cell disease status influenced outcomes, or modified the interaction with fever status on volume required. Fever status at the time of ordering blood was a reliable determinant of volume required for optimal outcome. Elevated heart and respiratory rates normalised irrespective of transfusion volume and without diuretics. By consensus, a transfusion management algorithm was developed, incorporating 3 additional measurements of Hb post-admission, alongside clinical monitoring. The proposed algorithm should help clinicians safely implement findings from TRACT. Further research should assess its implementation in routine clinical practice

Journal article

Mogire RM, Morovat A, Muriuki JM, Mentzer AJ, Webb EL, Kimita W, Ndungu FM, Macharia AW, Cutland CL, Sirima SB, Diarra A, Tiono AB, Lule SA, Madhi SA, Sandhu MS, Prentice AM, Bejon P, Pettifor JM, Elliott AM, Adeyemo A, Williams T, Atkinson SHet al., 2021, Prevalence and predictors of vitamin D deficiency in young African children, BMC Medicine, Vol: 19, Pages: 1-14, ISSN: 1741-7015

BackgroundChildren living in sub-Saharan Africa have a high burden of rickets and infectious diseases, conditions that are linked to vitamin D deficiency. However, data on the vitamin D status of young African children and its environmental and genetic predictors are limited. We aimed to examine the prevalence and predictors of vitamin D deficiency in young African children.MethodsWe measured 25-hydroxyvitamin D (25(OH)D) and typed the single nucleotide polymorphisms, rs4588 and rs7041, in the GC gene encoding the vitamin D binding protein (DBP) in 4509 children aged 0–8 years living in Kenya, Uganda, Burkina Faso, The Gambia and South Africa. We evaluated associations between vitamin D status and country, age, sex, season, anthropometric indices, inflammation, malaria and DBP haplotypes in regression analyses.ResultsMedian age was 23.9 months (interquartile range [IQR] 12.3, 35.9). Prevalence of vitamin D deficiency using 25(OH)D cut-offs of < 30 nmol/L and < 50 nmol/L was 0.6% (95% CI 0.4, 0.9) and 7.8% (95% CI 7.0, 8.5), respectively. Overall median 25(OH)D level was 77.6 nmol/L (IQR 63.6, 94.2). 25(OH)D levels were lower in South Africa, in older children, during winter or the long rains, and in those with afebrile malaria, and higher in children with inflammation. 25(OH)D levels did not vary by stunting, wasting or underweight in adjusted regression models. The distribution of Gc variants was Gc1f 83.3%, Gc1s 8.5% and Gc2 8.2% overall and varied by country. Individuals carrying the Gc2 variant had lower median 25(OH)D levels (72.4 nmol/L (IQR 59.4, 86.5) than those carrying the Gc1f (77.3 nmol/L (IQR 63.5, 92.8)) or Gc1s (78.9 nmol/L (IQR 63.8, 95.5)) variants.ConclusionsApproximately 0.6% and 7.8% of young African children were vitamin D deficient as defined by 25(OH)D levels < 30 nmol/L and < 50 nmol/L, respectively. Latitude, age, season, and p

Journal article

Maitland K, Kiguli S, Olupot-Olupot P, Hamaluba M, Thomas K, Alaroker F, Opoka RO, Tagoola A, Bandika V, Mpoya A, Mnjalla H, Nabawanuka E, Okiror W, Nakuya M, Aromut D, Engoru C, Oguda E, Williams TN, Fraser JF, Harrison D, Rowan K, on behalf of the COAST trial groupet al., 2021, Randomised controlled trial of oxygen therapy and high flow nasal therapy in African children with pneumonia, Intensive Care Medicine, Vol: 47, Pages: 566-576, ISSN: 0342-4642

PurposeThe life-saving role of oxygen therapy in African children with severe pneumonia is not yet established.MethodsThe open-label fractional-factorial COAST trial randomised eligible Ugandan and Kenyan children aged > 28 days with severe pneumonia and severe hypoxaemia stratum (SpO2 < 80%) to high-flow nasal therapy (HFNT) or low-flow oxygen (LFO: standard care) and hypoxaemia stratum (SpO2 80–91%) to HFNT or LFO (liberal strategies) or permissive hypoxaemia (ratio 1:1:2). Children with cyanotic heart disease, chronic lung disease or > 3 h receipt of oxygen were excluded. The primary endpoint was 48 h mortality; secondary endpoints included mortality or neurocognitive sequelae at 28 days.ResultsThe trial was stopped early after enrolling 1852/4200 children, including 388 in the severe hypoxaemia stratum (median 7 months; median SpO2 75%) randomised to HFNT (n = 194) or LFO (n = 194) and 1454 in the hypoxaemia stratum (median 9 months; median SpO2 88%) randomised to HFNT (n = 363) vs LFO (n = 364) vs permissive hypoxaemia (n = 727). Per-protocol 15% of patients in the permissive hypoxaemia group received oxygen (when SpO2 < 80%). In the severe hypoxaemia stratum, 48-h mortality was 9.3% for HFNT vs. 13.4% for LFO groups. In the hypoxaemia stratum, 48-h mortality was 1.1% for HFNT vs. 2.5% LFO and 1.4% for permissive hypoxaemia. In the hypoxaemia stratum, adjusted odds ratio for 48-h mortality in liberal vs permissive comparison was 1.16 (0.49–2.74; p = 0.73); HFNT vs LFO comparison was 0.60 (0.33–1.06; p = 0.08). Strata-specific 28 day mortality rates were, respectively: 18.6, 23.4 and 3.3, 4.1, 3.9%. Neurocognitive sequelae were rare.ConclusionsRespiratory support with HFNT showing potential benefit should prompt further trials.

Journal article

Muriuki JM, Mentzer AJ, Mitchell R, Webb EL, Etyang AO, Kyobutungi C, Morovat A, Kimita W, Ndungu FM, Macharia AW, Ngetsa CJ, Makale J, Lule SA, Musani SK, Raffield LM, Cutland CL, Sirima SB, Diarra A, Tiono AB, Fried M, Gwamaka M, Adu-Afarwuah S, Wirth JP, Wegmueller R, Madhi SA, Snow RW, Hill AVS, Rockett KA, Sandhu MS, Kwiatkowski DP, Prentice AM, Byrd KA, Ndjebayi A, Stewart CP, Engle-Stone R, Green TJ, Karakochuk CD, Suchdev PS, Bejon P, Duffy PE, Davey Smith G, Elliott AM, Williams TN, Atkinson SHet al., 2021, Malaria is a cause of iron deficiency in African children, Nature Medicine, Vol: 27, Pages: 653-658, ISSN: 1078-8956

Malaria and iron deficiency (ID) are common and interrelated public health problems in African children. Observational data suggest that interrupting malaria transmission reduces the prevalence of ID1. To test the hypothesis that malaria might cause ID, we used sickle cell trait (HbAS, rs334), a genetic variant that confers specific protection against malaria2, as an instrumental variable in Mendelian randomization analyses. HbAS was associated with a 30% reduction in ID among children living in malaria-endemic countries in Africa (n = 7,453), but not among individuals living in malaria-free areas (n = 3,818). Genetically predicted malaria risk was associated with an odds ratio of 2.65 for ID per unit increase in the log incidence rate of malaria. This suggests that an intervention that halves the risk of malaria episodes would reduce the prevalence of ID in African children by 49%.

Journal article

Petry N, Wirth JP, Adu-Afarwuah S, Wegmuller R, Woodruff BA, Tanumihardjo SA, Bentil H, Donkor WES, Williams TN, Shahab-Ferdows S, Selenje L, Mahama A, Steiner-Asiedu M, Rohner Fet al., 2021, Risk factors for anaemia among Ghanaian women and children vary by population group and climate zone, Maternal and Child Nutrition, Vol: 17, ISSN: 1740-8695

Anaemia has serious effects on human health and has multifactorial aetiologies. This study aimed to determine putative risk factors for anaemia in children 6-59 months and 15- to 49-year-old non-pregnant women living in Ghana. Data from a nationally representative cross-sectional survey were analysed for associations between anaemia and various anaemia risk factors. National and stratum-specific multivariable regressions were constructed separately for children and women to calculate the adjusted prevalence ratio (aPR) for anaemia of variables found to be statistically significantly associated with anaemia in bivariate analysis. Nationally, the aPR for anaemia was greater in children with iron deficiency (ID; aPR 2.20; 95% confidence interval [CI]: 1.88, 2.59), malaria parasitaemia (aPR 1.96; 95% CI: 1.65, 2.32), inflammation (aPR 1.26; 95% CI: 1.08, 1.46), vitamin A deficiency (VAD; aPR 1.38; 95% CI: 1.19, 1.60) and stunting (aPR 1.26; 95% CI: 1.09, 1.46). In women, ID (aPR 4.33; 95% CI: 3.42, 5.49), VAD (aPR 1.61; 95% CI: 1.24, 2.09) and inflammation (aPR 1.59; 95% CI: 1.20, 2.11) were associated with anaemia, whereas overweight and obese women had lower prevalence of anaemia (aPR 0.74; 95% CI: 0.56, 0.97). ID was associated with child anaemia in the Northern and Middle belts, but not in the Southern Belt; conversely, inflammation was associated with anaemia in both children and women in the Southern and Middle belts, but not in the Northern Belt. Anaemia control programmes should be region specific and aim at the prevention of ID, malaria and other drivers of inflammation as they are the main predictors of anaemia in Ghanaian children and women.

Journal article

Malinga J, Mogeni P, Omedo I, Rockett K, Hubbart C, Jeffreys A, Williams TN, Kwiatkowski D, Bejon P, Ross Aet al., 2020, Author Correction: Investigating the drivers of the spatio-temporal patterns of genetic differences between Plasmodium falciparum malaria infections in Kilifi County, Kenya., Scientific Reports, Vol: 10, Pages: 22416-22416, ISSN: 2045-2322

Journal article

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