Influence of malaria on markers of iron status in children: implications for interpreting iron status in malaria-endemic communities

Albumin levels in malaria patients: a systematic review and meta-analysis of their association with disease severity

Albumin, a key protein in human blood plasma, has been linked to various health conditions. However, its association with malaria, particularly in assessing disease severity, remains inadequately understood. This comprehensive systematic review and meta-analysis aimed to elucidate the relationship between albumin levels and malaria severity. A comprehensive literature search was conducted across multiple databases, including Embase, Scopus, PubMed, MEDLINE, Ovid, and Google Scholar, to identify studies examining albumin levels in malaria patients. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Data were pooled using a random-effects model, and heterogeneity was assessed using I2 statistics. Subgroup and meta-regression analyses were performed based on publication year, study location, and Plasmodium species. A total of 37 studies were included in this review. The thematic synthesis indicated that albumin levels in malaria patients varied significantly based on geographical location. A meta-analysis of 28 studies found that albumin levels were significantly lower in malaria patients compared with non-malarial controls (P < 0.001, standardized mean differences [SMD] = -2.23, 95% CI - 3.25 to - 1.20, I2: 98%, random effects model, 28 studies). Additionally, subgroup analysis revealed variations in albumin levels based on geographical location and Plasmodium species. Regarding the association with disease severity, thematic synthesis showed that severe malaria cases generally had decreased albumin levels across various regions. However, one Brazilian study reported higher albumin levels in severe cases. A separate meta-analysis of five studies found significantly lower albumin levels in patients experiencing severe malaria relative to those with less severe forms of the disease (P < 0.001, SMD = -0.66, 95% CI - 1.07 to - 0.25), I2: 73%, random effects model, 5 studies). This study underscores the clinical significance of albumin as a potential biomarker for Plasmodium infection and the severity of malaria. The findings suggest that albumin level monitoring could be crucial in managing malaria patients, especially in assessing disease severity and tailoring treatment approaches. Additional studies are required to investigate the underlying mechanisms driving these associations and validate the clinical utility of albumin levels in malaria patient management.

Standardisation and application of a novel multiplex assay for estimating micronutrient status and inflammatory markers in women of Sauria Paharia and Santhal tribes of Jharkhand

This study aimed to document the method standardisation and assessment of micronutrient and inflammatory markers in women from indigenous tribal communities of Jharkhand using a low-volume, high-throughput assay. This cross-sectional study was done among women of the reproductive age group from Sauria Paharia and Santhal tribal households (HH) in selected villages. Capillary blood samples were collected from the women during a HH survey to estimate ferritin, soluble transferrin receptor, retinol binding protein 4 and inflammatory biomarkers, C-reactive protein (CRP) and α-1-acid glycoprotein (AGP) using a multiplex assay. Vitamin D and Hb were estimated using an LC-MS technique and cyanmethaemoglobin method, respectively. A multiplex Luminex-based method was developed and standardised. The assay was used to estimate biomarkers in samples from 413 women (178 and 235 from Sauria Paharia and Santhal tribes, respectively). Over 51 % of women had raised CRP or AGP levels. Fe status was significantly better in Sauria Paharia compared with the Santhal women. Anaemia prevalence was 72 % among Santhal women. The proportion of women with Fe deficiency increased after adjusting for inflammation. The overall prevalence of vitamin A deficiency and insufficiency was 25 and 34 %, respectively, with similar prevalence in both tribes. All Santhal women had sufficient vitamin D levels, while 25 and 20 % of Sauria Paharia women had insufficient and deficient vitamin D levels, respectively. Our low-volume, high-throughput multiplex assays may provide a feasible approach for assessing nutritional biomarkers in nutritionally vulnerable hard-to-reach communities.

Levels of Serum Ferritin and Hepcidin in Patients with Uncomplicated Falciparum Malaria in Hodeidah, Yemen: Considerations for Assessing Iron Status

Understanding the key regulator of iron homeostasis is critical to the improvement of iron supplementation practices in malaria-endemic areas. This study aimed to determine iron indices and hepcidin (HEPC) level in patients infected with Plasmodium falciparum compared to apparently healthy, malaria-negative subjects in Hodeidah, Yemen. The study included 70 Plasmodium falciparum-infected and 20 malaria-negative adults. Blood films were examined for detection and estimation of parasitemia. Hemoglobin (Hb) level was measured using an automated hematology analyzer. Serum iron and total iron binding capacity (TIBC) were determined by spectrophotometric methods. Levels of serum ferritin (FER) and HEPC were measured by enzyme-linked immunosorbent assays. Data were stratified by sex and age. Comparable Hb levels were found in P. falciparum-infected patients and malaria-negative subjects in each sex and age group (p > 0.05). Compared to their malaria-negative counterparts, disturbed iron homeostasis in patients was evidenced by the significantly lower serum iron levels in females (p = 0.007) and those aged <25 years (p = 0.02) and the significantly higher TIBC in males (p = 0.008). Levels of serum FER and HEPC were significantly elevated in P. falciparum-infected patients compared to the corresponding malaria-negative participants (p < 0.001). Serum FER correlated positively with parasite density (p = 0.004). In conclusion, patients with uncomplicated P. falciparum in Hodeidah display elevated levels of serum HEPC and FER. Hemoglobin level may not reflect the disturbed iron homeostasis in these patients. The combined measurement of iron indices and HEPC provides comprehensive information on the iron status so that the right intervention can be chosen.

Toxicological effect of Artemisinin-Based Combination Therapies plus Paracetamol in malaria patients

BACKGROUND

Following the paucity of safety reports in the use of Artemisinin-Based Combination Therapies (ACTs) plus paracetamol, the study assessed safety potential of artemether-lumefantrine (ALP), artesunate-amodiaquine (AAP), artesunate-mefloquine (AMP), artesunate-sulphadoxine-pyrimethamine (ASPP) and dihydroartemisinin-piperaquine (DHPP) combination with paracetamol in malaria patients.

METHODS

ACTs and paracetamol were administered concomitantly in conventional doses/regimen to randomly selected patients. Blood samples were collected from the ante-cubital vein before and after completion of therapies. Toxicity markers such as weights, glucose, lipids, renal electrolytes, liver enzymes and haematological indices were assessed using standard protocols.

RESULTS

The total numbers of participants were 57 patients. Male to female ratio was 1:1.1. Mean body weight and ages were 59.19 ± 1.39 kg and 42.86 ± 1.32 years respectively. The mean temperatures prior to and after therapy were 37.49 ± 1.02 °C and 37.50 ± 0.17 °C respectively. Mean parasitaemia before the commencement of therapy was 6282 ± 21.01 parasites/μl. Out of thirty-seven toxicological indices evaluated, twenty-four were significantly altered by ACTs plus paracetamol (P < 0.05). Increased serum toxicity markers due to the drug combinations were glucose (AAP, AMP), urea (ALP, ASPP), bicarbonate ion (ALP, AAP, AMP, ASPP), chloride ion (ALP, AAP, AMP), creatinine (ALP, AAP, AMP, ASPP), alkaline phosphatase (ALP, AAP), aspartate aminotransferase and alanine aminotransferase (ALP, AAP, AMP, ASPP, DHPP), total protein (AMP, DHPP) and albumin (AMP, DHPP). Decreased serum toxicity markers due to the drugs were glucose (ALP, ASPP, DHPP), urea (AMP), bicarbonate ion (DHPP), chloride ion (ASPP, DHPP), creatinine (DHPP), alkaline phosphatase (AMP, ASPP, DHPP), total protein (ALP, AAP, and ASPP) and albumin (ALP, AAP, ASPP). Altered haematological indices were white blood cells, red blood cells, mean cell haemoglobin and platelets.

CONCLUSION

Since ACTs plus paracetamol altered human system, discrete selection is essential in managing uncomplicated malaria most especially in patients with co-morbid conditions.

The association of malaria morbidity with linear growth, hemoglobin, iron status, and development in young Malawian children: a prospective cohort study

Background

Although poor complementary feeding is associated with poor child growth, nutrition interventions only have modest impact on child growth, due to high burden of infections. We aimed to assess the association of malaria with linear growth, hemoglobin, iron status, and development in children aged 6–18 months in a setting of high malaria and undernutrition prevalence.

Methods

Prospective cohort study, conducted in Mangochi district, Malawi. We enrolled six-months-old infants and collected weekly data for ‘presumed’ malaria, diarrhea, and acute respiratory infections (ARI) until age 18 months. Change in length-for-age z-scores (LAZ), stunting, hemoglobin, iron status, and development were assessed at age 18 months. We used ordinary least squares regression for continuous outcomes and modified Poisson regression for categorical outcomes.

Results

Of the 2723 children enrolled, 2016 (74.0%) had complete measurements. The mean (standard deviation) incidences of ‘presumed’ malaria, diarrhea, and ARI, respectively were: 1.4 (2.0), 4.6 (10.1), and 8.3 (5.0) episodes/child year. Prevalence of stunting increased from 27.4 to 41.5% from 6 to 18 months. ‘Presumed’ malaria incidence was associated with higher risk of stunting (risk ratio [RR] = 1.04, 95% confidence interval [CI] = 1.01 to 1.07, p = 0.023), anemia (RR = 1.02, 95%CI = 1.00 to 1.04, p = 0.014) and better socio-emotional scores (B = − 0.21, 95%CI = − 0.39 to − 0.03, p = 0.041), but not with change in LAZ, haemoglobin, iron status or other developmental outcomes. Diarrhea incidence was associated with change in LAZ (B = − 0.02; 95% CI = − 0.03 to − 0.01; p = 0.009), stunting (RR = 1.02; 95% CI = 1.01 to 1.03; p = 0.005), and slower motor development. ARI incidence was not associated with any outcome except for poorer socio-emotional scores.

Conclusion

In this population of young children living in a malaria-endemic setting, with active surveillance and treatment, ‘presumed’ malaria is not associated with change in LAZ, hemoglobin, or iron status, but could be associated with stunting and anemia. Diarrhea was more consistently associated with growth than was malaria or ARI. The findings may be different in contexts where active malaria surveillance and treatment is not provided.

Trial registration

NCT00945698 (July 24, 2009) and NCT01239693 (November 11, 2010).

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.

How Eliminating Malaria May Also Prevent Iron Deficiency in African Children

Malaria and iron deficiency are common among children living in sub-Saharan Africa. Several studies have linked a child’s iron status to their future risk of malaria infection; however, few have examined whether malaria might be a cause of iron deficiency. Approximately a quarter of African children at any one time are infected by malaria and malaria increases hepcidin and tumor necrosis factor-α concentrations leading to poor iron absorption and recycling. In support of a hypothetical link between malaria and iron deficiency, studies indicate that the prevalence of iron deficiency in children increases over a malaria season and decreases when malaria transmission is interrupted. The link between malaria and iron deficiency can be tested through the use of observational studies, randomized controlled trials and genetic epidemiology studies, each of which has its own strengths and limitations. Confirming the existence of a causal link between malaria infection and iron deficiency would readjust priorities for programs to prevent and treat iron deficiency and would demonstrate a further benefit of malaria control.

Housing type and risk of malaria among under-five children in Nigeria: evidence from the malaria indicator survey

Background

Malaria remains one of the major causes of morbidity and mortality among under-five (U5) children in Nigeria. Though different environmental factors have been assessed to influence the distribution and transmission of malaria vectors, there is a dearth of information on how housing type may influence malaria transmission among U5 children in Nigeria. This study assessed the relationship between housing type and malaria prevalence among U5s in Nigeria.

Methods

A cross-sectional analysis of the nationally representative 2015 Nigeria malaria indicator survey data was done. A representative sample of 8148 households in 329 clusters was selected for the survey. Children aged 6–59 months in the selected households were tested for anaemia and malaria using the rapid diagnostic test (RDT) and the microscopy. Data were analysed using descriptive statistics, Pearson Chi square (χ²) and logistic regression models at 5% level of significance.

Results

The odds of malaria infection was significantly higher among older children aged 24–59 months (aOR = 4.8, CI 2.13–10.99, p < 0.001), and children who lived in houses built completely with unimproved materials (aOR = 1.4, CI 1.08–1.80, p = 0.01). Other predictors of malaria infection include living in a rural area (aOR = 1.5, CI 1.25–1.91, p = 0.01), ever slept under a long-lasting insecticide-treated net (aOR = 1.1, CI 0.26–4.79, p = 0.89) and in a room not sprayed with insecticide (aOR = 1.2, CI 0.64–2.31, p = 0.56). Children who were malaria positive showed a higher prevalence of severe anaemia on RDT (87.6%) and Microscopy (67.4%) than those who were not anaemic (RDT = 31.6%, Microscopy = 12.9%).

Conclusions

Non-improved housing predicted malaria infection among U5s in Nigeria. Improved housing is a promising means to support a more integrated and sustainable approach to malaria prevention. Education of the Nigerian people on the role of improved housing on malaria protection and empowerment of the public to adopt improved housing as well as overall enlightenment on ways to prevent malaria infection can help to augment the current malaria control measures among U5 children.

Adjusting ferritin concentrations for inflammation: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project

Background: The accurate estimation of iron deficiency is important in planning and implementing interventions. Ferritin is recommended as the primary measure of iron status, but interpretability is challenging in settings with infection and inflammation.Objective: We assessed the relation between ferritin concentrations and inflammation and malaria in preschool children (PSC) (age range: 6-59 mo) and women of reproductive age (WRA) (age range: 15-49 y) and investigated adjustment algorithms to account for these effects.Design: Cross-sectional data from 15 surveys for PSC (n = 27,865) and 8 surveys for WRA (24,844), from the Biomarkers Reflecting the Inflammation and Nutritional Determinants of Anemia (BRINDA) project were analyzed individually and combined with the use of a meta-analysis. Several approaches were explored to estimate depleted iron stores (ferritin concentration <12 μg/L in PSC and <15 μg/L in WRA) in inflammation and malaria settings as follows: 1) increase ferritin-concentration cutoff to <30 μg/L; 2) exclude individuals with C-reactive protein (CRP) concentrations >5 mg/L or α-1-acid glycoprotein (AGP) concentrations >1 g/L; 3) apply arithmetic correction factors; and 4) use a regression correction approach.Results: Depleted iron-store estimates incrementally increased as CRP and AGP deciles decreased (4% compared with 30%, and 6% compared with 29% from highest compared with lowest CRP deciles for pooled PSC and WRA, respectively, with similar results for AGP). Depending on the approach used to adjust for inflammation (CRP plus AGP), the estimated prevalence of depleted iron stores increased by 7-25 and 2-8 absolute median percentage points for PSC and WRA, respectively, compared with unadjusted values. Adjustment for malaria in addition to CRP and AGP did not substantially change the estimated prevalence of depleted iron stores.Conclusions: Our results lend support for the use of internal regression correction to estimate the prevalence of depleted iron stores in regions with inflammation. This approach appears to mathematically reflect the linear relation of ferritin concentrations with acute-phase proteins. More research is warranted to validate the proposed approaches, but this study contributes to the evidence base to guide decisions about how and when to adjust ferritin for inflammation.

Adjusting retinol-binding protein concentrations for inflammation: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project

Background: The accurate estimation of the prevalence of vitamin A deficiency (VAD) is important in planning and implementing interventions. Retinol-binding protein (RBP) is often used in population surveys to measure vitamin A status, but its interpretation is challenging in settings where inflammation is common because RBP concentrations decrease during the acute-phase response.Objectives: We aimed to assess the relation between RBP concentrations and inflammation and malaria in preschool children (PSC) (age range: 6-59 mo) and women of reproductive age (WRA) (age range: 15-49 y) and to investigate adjustment algorithms to account for these effects.Design: Cross-sectional data from 8 surveys for PSC (n = 8803) and 4 surveys for WRA (n = 4191) from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project were analyzed individually and combined with the use of a meta-analysis. Several approaches were explored to adjust RBP concentrations in PSC in inflammation and malaria settings as follows: 1) the exclusion of subjects with C-reactive protein (CRP) concentrations >5 mg/L or α-1-acid glycoprotein (AGP) concentrations >1 g/L, 2) the application of arithmetic correction factors, and 3) the use of a regression correction approach. The impact of adjustment on the estimated prevalence of VAD (defined as <0.7 μmol/L) was examined in PSC.Results: The relation between estimated VAD and CRP and AGP deciles followed a linear pattern in PSC. In women, the correlations between RBP and CRP and AGP were too weak to justify adjustments for inflammation. Depending on the approach used to adjust for inflammation (CRP+AGP), the estimated prevalence of VAD decreased by a median of 11-18 percentage points in PSC compared with unadjusted values. There was no added effect of adjusting for malaria on the estimated VAD after adjusting for CRP and AGP.Conclusions: The use of regression correction (derived from internal data), which accounts for the severity of inflammation, to estimate the prevalence of VAD in PSC in regions with inflammation and malaria is supported by the analysis of the BRINDA data. These findings contribute to the evidence on adjusting for inflammation when estimating VAD with the use of RBP.

Asymptomatic malaria, growth status, and anaemia among children in Lao People's Democratic Republic: a cross-sectional study

Background

Asymptomatic malaria can be observed in both stable endemic areas and unstable transmission areas. However, although much attention has been given to acute malaria infections, relatively little attention has been paid to asymptomatic malaria. Nonetheless, because the asymptomatic host serves as a reservoir for the malaria parasite, asymptomatic malaria is now recognized as an important obstacle to malaria elimination. Asymptomatic malaria is also associated with anaemia, a global public health problem with serious consequences on human health as well as social and economic development. In Lao People’s Democratic Republic (Lao PDR), malaria, anaemia, and malnutrition are serious public health concerns. However, few studies have focused on the relationship between these variables. Therefore, this study investigated the relationship between asymptomatic malaria, growth status, and the prevalence of anaemia among children aged 120 months old or younger in rural villages in Lao PDR.

Methods

In December 2010 and March 2011, data were collected from five villages in Savannakhet province. Anthropometric measurements, blood samples, and malaria rapid diagnostic tests were conducted. The presence of malaria was confirmed with polymerase chain reaction assays for Plasmodium falciparum. Underweight status, stunting, and anaemia were defined according to World Health Organization standards.

Results

The mean age of participants (n = 319) was 88.3 months old (Standard Deviation: 20.6, ranged from 30–119 months old), and 20 participants (6.3 %) had an asymptomatic malaria infection, 92 (28.8 %) were anaemic, 123 (38.6 %) were underweight, and 137 (42.9 %) were stunted. Stunted children were more likely to be infected with asymptomatic malaria [odds ratio (OR) 3.34, 95 % confidence interval (CI) 1.25–8.93], and asymptomatic malaria was associated with anaemia [OR 5.17, 95 % CI 1.99–13.43].

Conclusions

These results suggest a significant association between asymptomatic malaria and anaemia in children. Furthermore, stunted children were more likely to have lower Hb levels and to be infected with asymptomatic malaria than children without stunting. However, further studies examining the impact of asymptomatic malaria infection on children’s nutritional and development status are necessary.

Cassava Intake and Vitamin A Status among Women and Preschool Children in Akwa-Ibom, Nigeria

Background

As part of the HarvestPlus provitamin A-biofortified cassava program in Nigeria we conducted a survey to determine the cassava intake and prevalence of vitamin A deficiency among children 6-59 months and women of childbearing age in the state of Akwa Ibom.

Methods

A cluster-randomized cross-sectional survey was conducted in 2011 in Akwa Ibom, Nigeria. The usual food and nutrient intakes were estimated using a multi-pass 24-hour recall with repeated recall on a subsample. Blood samples of children and women were collected to analyze for serum retinol, serum ferritin, and acute phase proteins as indicators of infection. Vitamin A deficiency was defined as serum retinol <0.70 μmol/L adjusted for infection.

Results

A total of 587 households of a mother-child dyad participated in the dietary intake assessment. Cassava was very widely consumed in Akwa Ibom, mainly as gari or foofoo. Daily cassava consumption frequency was 92% and 95% among children and women, respectively. Mean (±SD) cassava intake (expressed as raw fresh weight) was 348 ± 317 grams/day among children and 940 ± 777 grams/day among women. Intakes of most micronutrients appeared to be adequate with the exception of calcium. Median vitamin A intake was very high both for children (1038 μg RAE/day) and women (2441 μg RAE/day). Red palm oil and dark green leafy vegetables were the main sources of vitamin A in the diet, with red palm oil alone contributing almost 60% of vitamin A intake in women and children. Prevalence of vitamin A deficiency ranged from moderate (16.9 %) among children to virtually non-existent (3.4 %) among women.

Conclusion

Consumption of cassava and vitamin A intake was high among women and children in Akwa Ibom with a prevalence of vitamin A deficiency ranging from moderate in children to non-existent among women. The provitamin A biofortified cassava and other vitamin A interventions should focus dissemination in states where red palm oil is not widely consumed.

Undernutrition, the acute phase response to infection, and its effects on micronutrient status indicators

Infection and undernutrition are prevalent in developing countries and demonstrate a synergistic relation. Undernutrition increases infection-related morbidity and mortality. The acute phase response (APR) is an innate, systemic inflammatory reaction to a wide array of disruptions in a host's homeostasis, including infection. Released from immune cells in response to deleterious stimuli, proinflammatory cytokines act on distant tissues to induce behavioral (e.g., anorexia, weakness, and fatigue) and systemic effects of the APR. Cytokines act to increase energy and protein requirements to manifest fever and support hepatic acute phase protein (APP) production. Blood concentrations of glucose and lipid are augmented to provide energy to immune cells in response to cytokines. Additionally, infection decreases intestinal absorption of nutrients and can cause direct loss of micronutrients. Traditional indicators of iron, zinc, and vitamin A status are altered during the APR, leading to inaccurate estimations of deficiency in populations with a high or unknown prevalence of infection. Blood concentrations of APPs can be measured in nutrition interventions to assess the time stage and severity of infection and correct for the APR; however, standardized cutoffs for nutrition applications are needed. Protein-energy malnutrition leads to increased gut permeability to pathogens, abnormal immune cell populations, and impaired APP response. Micronutrient deficiencies cause specific immune impairments that affect both innate and adaptive responses. This review describes the antagonistic interaction between the APR and nutritional status and emphasizes the need for integrated interventions to address undernutrition and to reduce disease burden in developing countries.

The acute phase response affected traditional measures of micronutrient status in rural Zambian children during a randomized, controlled feeding trial

The acute phase response (APR) to infection can alter blood-based indicators of micronutrient status. Data from a 3-mo randomized, controlled feeding trial in rural Zambian children (n = 181, aged 3-5 y) were used to determine the impact of the APR on indicators of vitamin A and iron status using baseline and final blood samples. Concentrations of acute phase proteins were categorized as raised C-reactive protein (CRP; >5 and >10 mg/L) only, both raised CRP and α1-acid glycoprotein (AGP; >1.2 g/L), raised AGP only, and neither CRP nor AGP raised to identify the respective stages of infection: incubation, early convalescence, convalescence, and healthy state. Data were insufficient to examine the incubation stage of infection. A CRP concentration of >5 mg/L was an effective elevation cutoff point in this population to show impact on micronutrient markers. Time did not affect hemoglobin, serum ferritin, or serum retinol concentrations (P > 0.05). During early convalescence, hemoglobin decreased (14-16%; P ≤ 0.05), serum ferritin increased (279-356%; P ≤ 0.05), and serum retinol decreased (20-30%; P ≤ 0.05). Serum retinol concentrations did not change during convalescence; however, hemoglobin remained depressed (4-9%) and serum ferritin was elevated (67-132%) (both P ≤ 0.05). Modified relative dose response values were unaffected by the APR (P > 0.05) but increased between time points (16%; P ≤ 0.05), indicating a decrease in liver vitamin A reserves on the background of a semiannual vitamin A supplementation program. The observed prevalence of anemia and vitamin A deficiency assessed by serum retinol concentration was higher during the APR (P ≤ 0.05). It is important to consider the impact of infection on dietary interventions and to adjust for acute phase proteins when assessing iron status or vitamin A status by serum retinol concentration alone in children.

The association between malaria and iron status or supplementation in pregnancy: a systematic review and meta-analysis

Introduction

Malaria prevention and iron supplementation are associated with improved maternal and infant outcomes. However, evidence from studies in children suggests iron may adversely modify the risk of malaria. We reviewed the evidence in pregnancy of the association between malaria and markers of iron status, iron supplementation or parenteral treatment.

Methods and Findings

We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, the Global Health Library, and the Malaria in Pregnancy library to identify studies that investigated the association between iron status, iron treatment or supplementation during pregnancy and malaria. Thirty one studies contributed to the analysis; 3 experimental and 28 observational studies. Iron supplementation was not associated with an increased risk of P. falciparum malaria during pregnancy or delivery in Africa (summary Relative Risk = 0.89, 95% Confidence Interval (CI) 0.66–1.20, I² = 78.8%, 5 studies). One study in Asia reported an increased risk of P. vivax within 30 days of iron supplementation (e.g. adjusted Hazard Ratio = 1.75, 95% CI 1.14–2.70 for 1–15 days), but not after 60 days. Iron deficiency (based on ferritin and C-reactive protein) was associated with lower odds for malaria infection (summary Odds Ratio = 0.35, 0.24–0.51, I² = 59.2%, 5 studies). With the exception of the acute phase protein ferritin, biomarkers of iron deficiency were generally not associated with malaria infection.

Conclusions

Iron supplementation was associated with a temporal increase in P vivax, but not with an increased risk of P. falciparum; however, data are insufficient to rule out the potential for an increased risk of P. falciparum. Iron deficiency was associated with a decreased malaria risk in pregnancy only when measured with ferritin. Until there is more evidence, it is prudent to provide iron in combination with malaria prevention during pregnancy.

[Evaluation of liver function in severe malaria in children under five in Kinshasa, Democratic Republic of the Congo]

Introduction

Méthodes

Résultats

Conclusion

Malaria and haematologic parameters of pupils at different altitudes along the slope of Mount Cameroon: a cross-sectional study

BACKGROUND

Haematologic abnormalities are features in Plasmodium falciparum infection, and anaemia is an inevitable outcome. This study examines the influence of malaria status and altitude on haematologic parameters in school-aged pupils.

METHODS

A cross-sectional study was conducted among 728 school pupils aged between four and 15 years at three different altitudinal ranges along the slope of the Mount Cameroon region. The investigative methods included the use of questionnaire, clinical evaluation and laboratory investigations. Blood sample collected from each child was used for the preparation of blood films for detection of malaria parasites and assessment of malaria parasite density as well as full blood count determination using an automated haematology analyzer.

RESULTS

The prevalence of malaria in the study population was 33.8% and 64.2% (158/246) of these were asymptomatic (AM). Pupils in lowlands had a significantly (P <0.05) prevalence (95% confidence interval, CI) of malaria (60.6%, CI = 54.6-65.9%) than those in middle belt (29.1%, CI = 23.9-34.8%) and highlands (7.7%, CI = 6.1-9.8%), while those in middle belt had significantly higher geometric mean parasite density (475) than those in lowlands (233) and highlands (388). The prevalence of malaria was significantly higher in children that presented with fever (40.4%, CI = 33.8-47.2%) when compared with afebrile subjects (31%, CI = 27-35.2%). Pupils with AM had a higher prevalence of leucopaenia (43.7%, CI = 35.8-51.8%), microcytosis (27.2%, CI = 20.5-34.9%), hypochromasia (27.8%, CI = 21-35.5%) and thrombocytopaenia (14.9%, CI = 8.9-22.8%) when compared with those with clinical malaria (CM). All mean haematological parameters were comparable in pupils with CM and AM, except for the mean white blood cell (WBC) counts. Pupils with AM had significantly lower (P = 0.02) mean WBC counts (5.1 ± 2.5 × 109/L) than those with CM (5.9 ± 2.3 × 109/L). Age, altitude and malaria parasitaemia was of significant influence on several haematological parameters.

CONCLUSION

Altitude influenced the distribution and density of malaria parasites and was of confounding influence on the haematologic profiles. These results highlight the insidious effects of AM on the haematologic components.

Haptoglobin phenotypes and iron status in children living in a malaria endemic area of Kenyan coast

Malaria infection may be affected by host genetic factors as well as nutritional status. Iron status and the phenotype of haptoglobin, a heme-binding acute phase reactant may be determinants of malaria parasitemia. A combination of cross sectional studies and longitudinal follow-up were used to describe the association between iron status, C-reactive protein, malaria infections and host genetic factors including; haptoglobin (Hp) phenotypes, in children below 9 years in a malaria endemic area in Coastal Kenya. The prevalence of 0.45 and 0.41, respectively for Hp 1-1 and Hp 2-1 phenotypes was significantly higher than 0.14 for Hp 2-2 phenotype (n=162). Children with Hp 2-2 phenotype showed significantly higher iron storage compared to those with Hp 1-1 and Hp 2-1 phenotypes when children with malaria parasites and high C-reactive protein (>9mg/L) were excluded from the analysis. There were no significant differences in malaria parasite densities among Hp phenotypes but children with Hp 2-2 had lower number of clinical malaria episodes (P=0.045). Taken together, this study shows that the presence of malaria may complicate the interpretation of iron status in children based on their Hp-phenotypes. Further studies will be required to address possible interactions among the various genetic factors and iron status in a malaria endemic setting.

Acute-phase proteins in pregnant Sudanese women with severe Plasmodium falciparum malaria

A case-control study was carried out in Kassala and Medani Maternity Hospitals in Sudan to investigate acute-phase proteins [haptoglobin, C-reactive protein (CRP), ferritin and albumin] in three groups of pregnant women (32 in each arm) comprising those with severe Plasmodium falciparum malaria or uncomplicated P. falciparum malaria and healthy controls. Whilst there was no significant difference in the levels of albumin and haptoglobin, ferritin and CRP levels were significantly higher in pregnant women with severe P. falciparum malaria. There were significant positive correlations between parasite count and haptoglobin, and medium positive correlations between parasite count and CRP.

Iron deficiency and acute seizures: results from children living in rural Kenya and a meta-analysis

Background

There are conflicting reports on whether iron deficiency changes susceptibility to seizures. We examined the hypothesis that iron deficiency is associated with an increased risk of acute seizures in children in a malaria endemic area.

Methods

We recruited 133 children, aged 3–156 months, who presented to a district hospital on the Kenyan coast with acute seizures and frequency-matched these to children of similar ages but without seizures. We defined iron deficiency according to the presence of malarial infection and evidence of inflammation. In patients with malaria, we defined iron deficiency as plasma ferritin<30µg/ml if plasma C-reactive protein (CRP) was<50mg/ml or ferritin<273µg/ml if CRP≥50mg/ml, and in those without malaria, as ferritin<12µg/ml if CRP<10mg/ml or ferritin<30µg/ml if CRP≥10mg/ml. In addition, we performed a meta-analysis of case-control studies published in English between January 1966 and December 2009 and available through PUBMED that have examined the relationship between iron deficiency and febrile seizures in children.

Results

In our Kenyan case control study, cases and controls were similar, except more cases reported past seizures. Malaria was associated with two-thirds of all seizures. Eighty one (30.5%) children had iron deficiency. Iron deficiency was neither associated with an increased risk of acute seizures (45/133[33.8%] cases were iron deficient compared to 36/133[27.1%] controls, p = 0.230) nor status epilepticus and it did not affect seizure semiology. Similar results were obtained when children with malaria, known to cause acute symptomatic seizures in addition to febrile seizures were excluded. However, in a meta-analysis that combined all eight case-control studies that have examined the association between iron deficiency and acute/febrile seizures to-date, iron deficiency, described in 310/1,018(30.5%) cases and in 230/1,049(21.9%) controls, was associated with a significantly increased risk of seizures, weighted OR 1.79(95%CI 1.03–3.09).

Conclusions

Iron deficiency is not associated with an increased risk of all acute seizures in children but of febrile seizures. Further studies should examine mechanisms involved and the implications for public health.

New cut-off values for ferritin and soluble transferrin receptor for the assessment of iron deficiency in children in a high infection pressure area

Background:

Due to the potential risk of iron supplementation in iron replete children, it is important to properly identify children who may require iron supplementation. However, assessment of the iron status has proven to be difficult, especially in children living in areas with high infection pressure (including malaria).

Aims and Methods:

Biochemical iron markers were compared to bone marrow iron findings in 381 Malawian children with severe anaemia.

Results:

Soluble transferrin receptor/log ferritin (TfR-F index), using a cut-off of 5.6, best predicted bone marrow iron stores deficiency (sensitivity 74%, specificity 73%, accuracy 73%). In order to improve the diagnostic accuracy of ferritin or sTfR as a stand-alone marker, the normal cut-off value needed to be increased by 810% and 83% respectively. Mean cell haemoglobin concentration (MCHC), using a cut-off of 32.1 g/dl, had a sensitivity of 67% and specificity of 64% for detecting iron stores deficiency.

Conclusion:

TfR-F index incorporated the high sensitivity of sTfR, a proxy for cellular iron need, and the high specificity of ferritin, a proxy for iron stores. In areas with a high infection pressure, the TfR-F index best predicted iron deficiency. However, in settings where diagnostic tests are limited, MCHC may be an acceptable alternative screening test.

Iron delocalisation in the pathogenesis of malarial anaemia

There is consensus that the pathophysiology of malaria-associated anaemia is multifactorial, but the precise mechanisms behind many of the haematological changes during malaria remain unclear. In this review, we attempt to build a composite picture of the pathophysiology of malarial anaemia using evidence from experimental, human and animal studies. We propose that cytokine- and hepcidin-mediated iron delocalisation, a principal mechanism in the anaemia of inflammation, plays an important role in the aetiology of malarial anaemia, and can explain some of the clinical and laboratory findings. These mechanisms interact with other aetiological determinants, such as dietary iron and micronutrient supply, helminth load, other infections and genetic variation, in determining the severity and associated features of anaemia. We suggest that iron delocalisation as a mechanism for malarial anaemia could be exploited for the development of alternative therapeutic strategies for post-malaria anaemia.

The health impact of polyparasitism in humans: are we under-estimating the burden of parasitic diseases?

Parasitic infections are widespread throughout the tropics and sub-tropics, and infection with multiple parasite species is the norm rather than the exception. Despite the ubiquity of polyparasitism, its public health significance has been inadequately studied. Here we review available studies investigating the nutritional and pathological consequences of multiple infections with Plasmodium and helminth infection and, in doing so, encourage a reassessment of the disease burden caused by polyparasitism. The available evidence is conspicuously sparse but is suggestive that multiple human parasite species may have an additive and/or multiplicative impact on nutrition and organ pathology. Existing studies suffer from a number of methodological limitations and adequately designed studies are clearly necessary. Current methods of estimating the potential global morbidity due to parasitic diseases underestimate the health impact of polyparasitism, and possible reasons for this are presented. As international strategies to control multiple parasite species are rolled-out, there is a number of options to investigate the complexity of polyparasitism, and it is hoped that that the parasitological research community will grasp the opportunity to understand better the health of polyparasitism in humans.

Iron incorporation and post-malaria anaemia

Background

Iron supplementation is employed to treat post-malarial anaemia in environments where iron deficiency is common. Malaria induces an intense inflammatory reaction that stalls reticulo-endothelial macrophagal iron recycling from haemolysed red blood cells and inhibits oral iron absorption, but the magnitude and duration of these effects are unclear.

Methodology/Principal Findings

We examined the red blood cell incorporation of oral administered stable isotopes of iron and compared incorporation between age matched 18 to 36 months old children with either anaemia post-malaria (n = 37) or presumed iron deficiency anaemia alone (n = 36). All children were supplemented for 30 days with 2 mg/kg elemental iron as liquid iron sulphate and administered ⁵⁷Fe and ⁵⁸Fe on days 1 and 15 of supplementation respectively. ⁵⁷Fe and⁵⁸Fe incorporation were significantly reduced (8% vs. 28%: p<0.001 and 14% vs. 26%: p = 0.045) in the malaria vs. non-malaria groups. There was a significantly greater haemoglobin response in the malaria group at both day 15 (p = 0.001) and 30 (p<0.000) with a regression analysis estimated greater change in haemoglobin of 7.2 g/l (s.e. 2.0) and 10.1 g/l (s.e. 2.5) respectively.

Conclusion/Significance

Post-malaria anaemia is associated with a better haemoglobin recovery despite a significant depressant effect on oral iron incorporation which may indicate that early erythropoetic iron need is met by iron recycling rather than oral iron. Supplemental iron administration is of questionable utility within 2 weeks of clinical malaria in children with mild or moderate anaemia.

Iron metabolism and malaria

Recent evidence from a large, randomized, controlled trial has suggested that the universal administration of iron to children in malaria-endemic areas is associated with an increase in adverse health outcomes. The purpose of this paper is to summarize the available ecologic and intervention trials related to iron and malaria in children, and to set these against current knowledge of the biology of host-pathogen interactions involving iron metabolism. We conclude that, although not fully consistent, the balance of evidence confirms that administration of iron (usually in combination with folic acid) increases the incidence of malaria when given without prophylaxis and in the absence of universal access to treatment. The mechanisms by which additional iron can benefit the parasite are far from clear. There is evidence to suggest that the apparent detrimental effect of iron supplementation may vary according to levels of antecedent iron status, the presence of hemoglobinopathies and glucose-6-phosphate dehydrogenase (G6PD) deficiency, and other host genetic variants, such as variants in haptoglobin. The effects of malaria on host iron metabolism are also reviewed and reveal that the key cause of malaria-induced anemia is a maldistribution of iron and suppression of erythropoiesis rather than an exacerbation of gross iron deficiency. We tentatively conclude that, if it is to be recommended, universal iron supplementation in malarious areas should only be considered in conjunction with some form of prophylaxis (e.g., intermittent preventive therapy [IPT]) or in the context of good health services with ready access to facilities for malaria diagnosis and treatment. An alternative approach would be to screen for anemia and target supplementation only to anemic children. With regard to treatment, there is good evidence that iron supplementation should be withheld until the treatment schedule is complete, both because iron may inhibit treatment and because the absorption of oral iron is blocked by the inflammatory response.

Maternal peripheral blood level of IL-10 as a marker for inflammatory placental malaria

BACKGROUND

Placental malaria (PM) is an important cause of maternal and foetal mortality in tropical areas, and severe sequelae and mortality are related to inflammation in the placenta. Diagnosis is difficult because PM is often asymptomatic, peripheral blood smear examination detects parasitemia as few as half of PM cases, and no peripheral markers have been validated for placental inflammation.

METHODS

In a cohort of Tanzanian parturients, PM was determined by placental blood smears and placental inflammation was assessed by histology and TNF mRNA levels. Maternal peripheral blood levels of several immune mediators previously implicated in PM pathogenesis, as well as ferritin and leptin were measured. The relationship between the levels of these soluble factors to PM and placental inflammation was examined.

RESULTS

Peripheral levels of TNF, TNF-RI, TNF-RII, IL-1, IL-10, and ferritin were elevated during PM, whereas levels of IFN-gamma, IL-4, IL-5 and IL-6 were unchanged and levels of leptin were decreased. In receiver operating characteristic curve analysis, IL-10 had the greatest area under the curve, and would provide a sensitivity of 60% with a false positive rate of 10%. At a cut off level of 15 pg/mL, IL-10 would detect PM with a sensitivity of 79.5% and a specificity of 84.3%. IL-10 levels correlated with placental inflammatory cells and placental TNF mRNA levels in first time mothers.

CONCLUSION

These data suggest that IL-10 may have utility as a biomarker for inflammatory PM in research studies, but that additional biomarkers may be required to improve clinical diagnosis and management of malaria during pregnancy.

Iron deficiency and NRAMP1 polymorphisms (INT4, D543N and 3'UTR) do not contribute to severity of anaemia in tuberculosis in the Indonesian population

Fe-deficiency anaemia is the most common cause of anaemia in developing countries. In these settings, many chronic infections, including tuberculosis (TB), are highly prevalent. Fe is an essential nutrient for both host and mycobacteria that play a pivotal role in host immunity and mycobacterial growth. A case-control study was performed in a TB-endemic region in Jakarta, Indonesia, among 378 pulmonary TB patients and 436 healthy controls from the same neighbourhood with the same socio-economic status. In a number of these subjects the Fe status could be explored. The distribution of three polymorphisms in the natural resistance-associated macrophage protein gene (NRAMP1) including INT4, D543N and 3'UTR was examined for a possible association with susceptibility to TB. Anaemia (corrected for sex) was present in 63.2 % of active TB compared with 6.8 % of controls, with female patients more often affected. Anaemia was more pronounced in advanced TB as diagnosed by chest radiography. Lower Hb concentrations in TB patients were accompanied by lower plasma Fe concentrations, lower Fe-binding capacity and higher plasma ferritin. After successful TB therapy, Fe parameters improved towards control values and Hb levels normalised, even without Fe supplementation. NRAMP1 gene polymorphisms were not associated with TB susceptibility, TB severity or anaemia. In conclusion, most active TB patients had anaemia, which was probably due to inflammation and not to Fe deficiency since TB treatment without Fe supplementation was sufficient to restore Hb concentration.

Interpretation of serum ferritin concentrations as indicators of total-body iron stores in survey populations: the role of biomarkers for the acute phase response

BACKGROUND

Nutritional surveys use acute phase protein (APP) biomarkers such as C-reactive protein (CRP) and alpha1-acid glycoprotein (AGP) to identify the influence of inflammation on the distribution of iron status biomarkers. Few, however, have examined which biomarker better identifies persons with spurious elevations in iron status markers.

OBJECTIVE

We explored the relations of APP biomarkers to iron-status biomarkers in infants and school-age children.

DESIGN

In screening surveys, we identified a sample of African American infants (n = 351) and Guatemalan school-age children (n = 375). We used a common set of APP and iron-status biomarkers to examine the association between the 2 sets of markers (laboratory variables).

RESULTS

The overall prevalence of either inflammation or iron deficiency was <10% in both samples. The log AGP and CRP values were significantly correlated (r = 0.70), but the unexplained variance still was >50%. Serum ferritin-but not transferrin receptor, transferrin receptor index, or serum iron-was related to APP concentrations, but poor positive predictive value (<72%) and low kappa scores were found. Ferritin concentrations >1 geometric SD above the geometric mean were poorly predicted by either elevated AGP or CRP. Qualitative CRP analysis was not effective in identifying persons who had other indications of mild inflammation.

CONCLUSIONS

These analyses show that a low prevalence of inflammation has little influence on the distribution of ferritin, and 2 common indicators of inflammation do not perform equally well in identifying persons who may have elevations in ferritin due to inflammation.

Epidemiology of malaria transmission in forest and plain ecotype villages in Sundargarh District, Orissa, India

A study of the epidemiology of malaria transmission was undertaken in 13 tribal villages located in forest and plain areas of Sundargarh District of Orissa state, India, from January 2001 to December 2003. In forest areas, intense transmission of malaria is attributed to the highly anthropophagic vector Anopheles fluviatilis sibling species S and is complemented by A. culicifacies sibling species C. In plain areas, A. culicifacies sibling species C is responsible for malaria transmission. The entomological inoculation rate in the forest and plain areas was 0.311 and 0.014 infective bites/person/night, respectively, during 2003. Malaria transmission is perennial both in forest and plain areas but is markedly low in the plain area compared with the forest area. Plasmodium falciparum accounted for 85.0% of the total malaria cases during the study period. In forest and plain areas, the number of P. falciparum cases per 1000 population per year was 284.1 and 31.2, respectively, whereas the parasite rate was 14.0% and 1.7%, respectively. In forest areas, clinical malaria occurs more frequently in children aged 0-5 years and declines gradually with increasing age. The study showed that villages in forest and plain areas separated by short geographical distances have distinct epidemiology of malaria transmission.

Seasonal childhood anaemia in West Africa is associated with the haptoglobin 2-2 genotype

BACKGROUND

Anaemia is a major cause of morbidity and mortality for children in Africa. The plasma protein haptoglobin (Hp) binds avidly to free haemoglobin released following malaria-induced haemolysis. Haptoglobin polymorphisms result in proteins with altered haemoglobin-binding capacity and different antioxidant, iron-recycling, and immune functions. Previous studies examined the importance of haptoglobin polymorphism in malaria and iron homeostasis, but it is unknown whether haptoglobin genotype might be a risk factor for anaemia in children in a malaria-endemic area.

METHODS AND FINDINGS

A cohort of 780 rural Gambian children aged 2-6 y was surveyed at the start and end of the malaria season. Samples were taken to assess haemoglobin (Hb) concentration, iron status (ferritin, zinc protoporphyrin, transferrin saturation, and soluble transferrin receptor concentration), haptoglobin concentration, alpha-1-antichymotrypsin (a measure of inflammation), and malaria parasites on blood film. We extracted DNA and genotyped for haptoglobin, sickle cell, and glucose-6-phosphate (G6PD) deficiency. Mean Hb levels fell over the malaria season. Children with the haptoglobin 2-2 genotype (17%) had a greater mean drop in Hb level over the malaria season (an 8.9 g/l drop; confidence interval [CI] 5.7, 12.1) compared to other children (a 5.1 g/l drop; CI 3.8, 6.4). In multivariate regression analysis, controlling for baseline Hb level, age group, village, malaria parasites on blood film, iron status, haptoglobin concentration, and G6PD deficiency, haptoglobin genotype predicted Hb level at the end of the malaria season (p = 0.0009, coefficient = -4.2). Iron status was not influenced by haptoglobin genotype.

CONCLUSIONS

The finding that haptoglobin 2-2 genotype is a risk factor for anaemia in children in a malaria-endemic area may reflect the reduced ability of the Hp2-2 polymer to scavenge free haemoglobin-iron following malaria-induced haemolysis. The magnitude of the effect of haptoglobin genotype (4 g/l Hb difference, p = 0.0009) was comparable to that of G6PD deficiency or HbAS (3 g/l difference, p = 0.03; and 2 g/l difference, p = 0.68, respectively).

Animal Source Foods Improve Dietary Quality, Micronutrient Status, Growth and Cognitive Function in Kenyan School Children: Background, Study Design and Baseline Findings

A previous longitudinal three-country study in Egypt, Kenya and Mexico found significant positive associations between intake of animal source foods (ASF) and growth, cognitive development and physical activity. To test for a causal relationship, a controlled school feeding intervention study was designed to test the hypotheses that ASF would improve micronutrient status, growth and cognitive function in Kenyan primary school children. Twelve rural Kenyan schools with 554 children were randomized to four feeding interventions using a local vegetable stew as the vehicle. The groups were designated as Meat, Milk, Energy and Control, who received no feedings. Feeding was carried out on school days for seven terms during 21 mo. Preintervention baseline measures included nutritional status, home food intake, anthropometry, biochemical measures of micronutrient status, malaria, intestinal parasites, health status and cognitive and behavioral measures. The measurements of each child were repeated at intervals over 2 y. Baseline data revealed stunting and underweight in approximately 30% of children and widespread inadequate intakes and/or biochemical evidence of micronutrient deficiencies, particularly of iron, zinc, vitamins A and B-12, riboflavin and calcium. Little or no ASF were eaten and fat intake was low. Malaria was present in 31% of children, and hookworm, amebiasis and giardia were widely prevalent. The outcomes measured were rates of change or increase during the intervention in cognitive function, growth, physical activity and behavior and micronutrient status. Hierarchical linear random effects modeling was used for analysis of outcomes.

Effect of iron supplementation on mild to moderate anaemia in pulmonary tuberculosis

Anaemia is a common complication of pulmonary tuberculosis. The precise mechanism of anaemia in pulmonary tuberculosis is not clearly known, but anaemia of inflammation as well as of Fe deficiency has been implicated. Both are common in developing countries. It is extremely difficult to distinguish anaemia of Fe deficiency from anaemia of inflammation with the haematological indices used routinely. Therefore, Fe preparations are usually prescribed for all anaemic patients irrespective of the aetiology. This approach has been questioned. The present study aimed to assess the effect of Fe supplementation on anaemic patients with pulmonary tuberculosis. Adult male patients 15-60 years of age with pulmonary tuberculosis and a blood haemoglobin concentration 80-110 g/l were included in the study; healthy adult males matched for age and socio-economic status were taken as controls. Blood haemoglobin concentration, total erythrocyte count (TEC), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin and serum Fe, total Fe-binding capacity and ferritin were estimated before treatment and 1, 2 and 6 months after treatment. The patients were divided randomly into three groups and during the initial 2 months of treatment were provided with one of three supplementary regimens consisting of placebo, Fe alone or Fe with other haematinics. Significant improvements in haematological indices and Fe status were noticed in all three groups. Blood haemoglobin concentration, MCV and PCV were significantly higher at 1 month in both Fe-supplemented groups than the placebo group. This difference, however, disappeared at 2 and 6 months with similar values in all three groups. The increase of other haematological indices was similar in all groups. Serum Fe and Fe saturation of transferrin were significantly higher in both Fe-supplemented groups than the placebo group up to 2 months; this effect, however, disappeared at 6 months. There was a consistent increase in TEC and decrease in ferritin values up to 6 months in all groups. Radiological and clinical improvement was similar in all three groups. These observations suggest that Fe supplementation in mild to moderate anaemia associated with pulmonary tuberculosis accelerated the normal resumption of haematopoiesis in the initial phases by increasing Fe saturation of transferrin. However, consistent improvement of haematological status was dependent only on the improvement of the disease process.

Malarial anemia leads to adequately increased erythropoiesis in asymptomatic Kenyan children

Malarial anemia is associated with a shift in iron distribution from functional to storage compartments. This suggests a relative deficit in erythropoietin production or action similar to that observed in other infections. Our study in Kenyan children with asymptomatic malaria aimed at investigating whether malaria causes increased erythropoiesis, and whether the erythropoietic response appeared appropriate for the degree of resulting anemia. Longitudinal and baseline data were used from a trial with a 2 x 2 factorial design, in which 328 anemic Kenyan children were randomly assigned to receive either iron or placebo, and sulfadoxine-pyrimethamine or placebo. Erythropoiesis was evaluated by serum concentrations of erythropoietin and soluble transferrin receptor. Prospectively collected data showed that malarial infection resulted in decreased hemoglobin concentrations, and increased serum concentrations of erythropoietin and transferrin receptor. Conversely, disappearance of malarial antigenemia resulted in increased hemoglobin concentrations, and decreased concentrations of these serum indicators. Additionally, our baseline data showed that current or recent malarial infection is associated with increased serum concentrations of erythropoietin and transferrin receptor, and that these were as high as or perhaps even higher than values of children without malarial infection and without inflammation. Our findings indicate that in asymptomatic malaria, the erythropoietic response is adequate for the degree of anemia, and that inflammation probably plays no or only a minor role in the pathogenesis of the resulting anemia. Further research is needed to demonstrate the role of deficient erythropoietin production or action in the pathogenesis of the anemia of symptomatic malaria.

Iron supplements: scientific issues concerning efficacy and implications for research and programs

Iron supplementation remains an important strategy for the prevention and treatment of iron deficiency anemia and can produce substantial improvements in the functional performance of iron deficient individuals and populations. Many potential benefits of iron supplementation require further exploration, including its effect on vitamin A and iodine metabolism. There is strong evidence that vitamin A and riboflavin deficiencies affect iron utilization from supplements and are important on a global scale, but little evidence that folate and vitamin B-12 deficiencies play a major causal role in the global burden of anemia. The efficacy of multiple micronutrient supplements for the prevention and treatment of anemia must be further evaluated. Because weekly supplementation with iron is effective at improving iron status, this option should be thoroughly explored and evaluated in the context of programs for the prevention and the treatment of iron deficiency and anemia. More conformation is warranted concerning the number of tablets that must be consumed in different situations, and the efficacy of supplying other micronutrients weekly with iron. Weekly supplementation programs may improve the logistical and economic constraints that currently limit the provision of supplements to the many target population groups for whom they are recommended, but usually fail to reach. Further work is required to clarify the purpose, delivery and outcomes of iron supplementation programs.

Serum transferrin receptor concentration indicates increased erythropoiesis in Kenyan children with asymptomatic malaria

BACKGROUND

Serum transferrin receptor concentrations indicate both erythropoietic activity and the deficit of functional iron in the erythron. In contrast with serum ferritin concentrations, serum transferrin receptor concentrations are not or are only marginally influenced by the inflammatory response to infection.

OBJECTIVE

We assessed iron status and examined the relation between serum transferrin receptor concentrations and malaria in children aged 2-36 mo who were asymptomatic for malaria.

DESIGN

This was a community-based cluster survey (n = 318).

RESULTS

Prevalences of malaria, anemia (hemoglobin concentration <110 g/L), iron deficiency (serum ferritin concentration <12 microg/L), and iron deficiency anemia were 18%, 69%, 53%, and 46%, respectively. Malaria was associated with lower mean hemoglobin concentrations (92.7 compared with 104.1 g/L; P = 0.0001) and higher geometric mean serum concentrations of transferrin receptor (11.4 compared with 7.8 mg/L; P = 0.005), ferritin (21.6 compared with 11.9 microg/L; P = 0.05), and C-reactive protein (12.5 compared with 6.8 mg/L; P = 0.004). There was no evidence for an association between serum concentrations of C-reactive protein and transferrin receptor. Children with malaria had higher serum transferrin receptor concentrations than expected for the degree of anemia, even after adjustment for inflammation indicated by serum C-reactive protein concentration quartiles (P = 0.02).

CONCLUSIONS

Our findings are consistent with the notion that malaria-induced hemolysis is accompanied by increased erythropoiesis. Serum transferrin receptor concentration is not useful for detecting iron deficiency in individuals with malaria. Individuals with high concentrations of serum C-reactive protein or similar acute phase reactants should be excluded from analysis if serum ferritin concentrations <12 microg/L are to be used to measure iron deficiency in malaria-endemic areas.

Randomized, controlled trial of single versus 3-times-daily ferrous sulfate drops for treatment of anemia

OBJECTIVE

Adherence to treatment of iron-deficiency anemia often is poor in both developed and developing countries. The current standard therapy is ferrous sulfate drops (or syrup) administered 3 times daily. It is possible that adherence would improve with a single-dose daily treatment regimen. We compared the use of single versus 3-times-daily ferrous sulfate drops, at the same total iron dose, on treatment of anemia in infants.

METHODS

To obtain a large enough cohort of anemic subjects, we performed the study in rural Ghana. Using a prospective, randomized, controlled design, we studied 557 anemic children (age range: 6-24 months; hemoglobin values: 70-99 g/L). One group (n = 280) received ferrous sulfate drops once daily (40 mg elemental iron), and the control group (n = 277) received ferrous sulfate drops 3 times per day (total dose, 40 mg elemental iron). Treatment lasted for 2 months. Hemoglobin and serum ferritin values were measured at baseline and at the end of the study.

RESULTS

Successful treatment of anemia (hemoglobin >100 g/L) occurred in 61% of the single-dose and in 56% of the 3-times-daily group. Geometric mean ferritin levels increased significantly in each group from baseline to the final visit. Side effects were minimal and similar between the 2 groups.

CONCLUSION

A single versus a 3-times-daily dose of ferrous sulfate drops over 2 months resulted in a similar rate of successful treatment of anemia, without side effects. To our knowledge, this is the first demonstration of the use of a single-dose daily regimen to treat anemia. Although not examined in the current study, use of a single-dose daily regimen may improve adherence to treatment of anemia in infants.

Serum ferritin and other haematological measurements in apparently healthy adults with malaria parasitaemia in Lagos, Nigeria

We studied 300 apparently healthy residents of Lagos aged 16-57 years. Their mean ferritin levels were 99.6 +/- 50.5 microg/l (men aged 20-57) and 66.5 +/- 44 microg/l (women aged 20-53) in aparasitaemic individuals. In parasitaemic subjects, mean ferritin levels were 133.1 +/- 48.3 microg/l (men aged 20-56) and 114.8 +/- 51.1 microg/l (women aged 16-50). Mean haematocrit values for aparasitaemic males were 45.7 +/- 5.6% and 37.9 +/- 5% for females, while mean haemoglobin levels were 153.2 +/- 1.5 microg/l and 124 +/- 3 microg/l, respectively. The mean values for MCV (mean corpuscular volume), MCH (mean corpuscular haemoglobin), MCHC (mean corpuscular haemoglobin concentration) were 101.7 +/- 8fl, 30.6 +/- 2.2 pg, 335 +/- 0.4 g/l and 99.8 +/- 10.1fl, 29.1 +/- 6.5 pg, 335 +/- 6 g/l. Serum iron levels were 34.2 +/- 5 micromol/l and 29.5 +/- 77 micromol/l. All haematological parameters measured were similar in both malaria parasitaemia positive and negative subjects, except ferritin level which was significantly higher in parasitaemic individuals (P < 0.05). Ferritin concentration and malaria density (r = 0.76 in males, r = 0.74 in females, P < 0.05) were positively correlated. Ferritin levels of subjects infected with Plasmodium falciparum were significantly higher than of those infected with P. malariae (P < 0.05). Hence ferritin estimation without examination for malaria parasitaemia in a malaria-endemic region such as Nigeria is not reliable. Asymptomatic malaria parasitaemia increases the ferritin level. Considering the mean ferritin level we found in normal subjects on a balanced diet, routine iron supplementation may not be necessary in the treatment of malaria-induced anaemia in Nigeria.

Impact of acute malaria on plasma concentrations of transferrin receptors

The acute-phase response to infection alters the plasma concentrations of most biochemical measures of iron status, rendering assessment of status difficult. Soluble transferrin receptors (TfR) may be an exception but have not been examined longitudinally during the major metabolic and inflammatory changes which occur during clinical malaria. Blood samples were collected daily during hospitalization, and again at a follow-up 2-6 weeks after discharge, from adult, mainly European, patients (n = 49) who developed uncomplicated Plasmodium falciparum malaria following visits to endemic areas. Parasitaemia and plasma concentrations of ferritin, TfR, C-reactive protein (CRP), alpha 1-acid glycoprotein (AGP) and alpha 1-antichymotrypsin (ACT) were measured. The concentrations of CRP, AGP and ACT correlated highly (P < 0.001) with each other and with plasma ferritin, and were significantly higher (P < 0.05) at all time points in hospital compared to the follow-up. TfR concentration correlated negatively and significantly (P < 0.05) with AGP and CRP but not with ACT or ferritin, and was significantly lower (around 30%) at all time points in hospital compared to follow-up, although in only 1 subject did it ever fall outside the normal reference range. In areas where both iron deficiency and clinical episodes of malaria are common, plasma TfR values need to be interpreted cautiously as indicators of iron status.

Severe linear growth retardation in rural Zambian children: the influence of biological variables

BACKGROUND

The prevalence of stunting in preschool children in Zambia is high; stunting has detrimental effects on concurrent psychomotor development and later working capacity.

OBJECTIVE

Our objective was to investigate biological variables that may contribute to linear growth retardation in preschool children in Samfya District, Zambia.

DESIGN

Children aged 6-9 mo (n = 108) and 14-20 mo (n = 102) attending mother-and-child health clinics were included. With a mixed-longitudinal design, they were followed up 9 and 21 mo later. Height and weight of children and their mothers were measured. Biochemical measures (eg, serum zinc, retinol, thyrotropin, iron, and acute phase protein concentrations), malaria parasitemia, and intestinal parasitosis were assessed.

RESULTS

Height-for-age z scores (HAZ) were low, indicating a high prevalence of stunting (36-79%). Ninety percent of the children were anemic, 53-71% had elevated acute phase proteins, and 80% had malaria parasitemia. Regression analyses showed that maternal height predicted the children's height at 6-9 mo (regression coefficient = 0.05; 95% CI: 0.02, 0.08). The children's height at an early age (6-9 and 14-20 mo) showed a strong relation with their height at later ages (22-30 and 34-41 mo). Serum micronutrient status did not show a significant relation with later HAZ.

CONCLUSION

Unlike other studies, we did not identify specific biological factors, such as health and micronutrient status, which contribute to the retardation of linear growth. The normal zinc and iodine statuses of the children suggest that at least these factors are not causal.