Impact of iron supplementation on schistosomiasis control in Zambian school children in a highly endemic area

Childhood Anemia and Risk for Acute Respiratory Infection, Gastroenteritis, and Urinary Tract Infection: A Systematic Review

Objective Children younger than 5 years, particularly children below 2 years, are among the most vulnerable groups for developing anemia and infections. This review is intended to assess the association between anemia and childhood acute respiratory infections (ARTIs), acute gastroenteritis (AGE), and urinary tract infections (UTIs).

Methods PubMed was searched for published articles from January 2000 to August 2021 in English using the following terms: anemia and acute respiratory tract infections in children; anemia and UTIs in children; anemia and AGE in children. The data extraction were conducted by two investigators using the same methodology. Using descriptive statistics, the data from different sources were synthesized, including medians and ranges.

Results A total of 426 articles and 27 original articles and 1 systematic review were included. Iron deficiency anemia is common among children between 6 months and 3 years of age. This age group can be considered a highly susceptible age for contraction of ARTI and AGE. Children below 5 years suffer five to six episodes of acute ARTI per year on average, and pneumonia accounts for the highest number of deaths, which is around 1.1 million each year. When considered, the odds ratio of anemia to increase the susceptibility of contracting lower ARTI would range from 2 to 5.7. Also, anemic children were 10 times more susceptible to developing acute recurrent ARTI and 4 times more susceptible to contracting pneumonia. Respiratory syncytial virus is the commonest viral etiology. Anemia would increase the risk of diarrhea by 2.9-fold in toddlers, while mild anemia, moderate anemia, and severe anemia would increase the susceptibility to contract AGE by 1.6, 1.6, and 8.9 times, respectively. Rotavirus is the commonest etiology. Some studies observed a protective effect of mild to moderate iron-deficient anemia from respiratory infections.

Conclusion Infectious disease imposes a heavy burden on the health sector in a country. The highest susceptibility for infections and the development of anemia would be due to inadequate nutrition supplementation to meet the demand during rapid body growth. Therefore, based on the available evidence, one can take the necessary steps to reduce the infectious disease burden by correcting the anemia status in children.

Interventions for Neglected Tropical Diseases Among Children and Adolescents: A Meta-analysis

BACKGROUND

Neglected tropical diseases (NTDs) are a group of communicable diseases affecting the poorest populations around the world.

OBJECTIVE

To assess the effectiveness of interventions, including mass drug administration (MDA), water, sanitation, and hygiene (WASH), vector control, health education, and micronutrients supplementation, for NTDs among children and adolescents.

METHODS

We conducted a literature search on the Cochrane Controlled Trials Register, Medline, and other databases until December 2020. We included randomized controlled trials and quasi-experimental studies conducted among children and adolescents. Two authors independently screened studies for relevance. Two authors independently extracted data, assessed the risk of bias, performed metaanalysis, and rated the quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation.

RESULTS

We included 155 studies (231 articles) involving 262 299 participants. For soil-transmitted helminthiasis, MDA may reduce the prevalence of Ascaris, Trichuris, and hookworm by 58%, 36%, and 57%, respectively. We are uncertain of the effect of health education, WASH, and iron supplementation on soil-transmitted helminthiasis prevalence. For Schistosomiasis, health education probably reduces the intensity and prevalence of S. mansoni, whereas micronutrient supplementation may reduce anemia prevalence and the infection intensity of S. hematobium compared with no supplementation. We are uncertain of the effect of MDA and vector control on Schistosomiasis outcomes. For trachoma, health education probably reduces the prevalence of active Trachoma, whereas we are uncertain of the effect of MDA, WASH, and vector control on Trachoma outcomes. There is limited data on the effectiveness of interventions for NTDs targeting children and adolescents.

CONCLUSION

Future studies are needed to evaluate the relative effectiveness and cost-effectiveness of various interventions specifically targeting children and adolescents.

Supplementation with micronutrients and schistosomiasis: systematic review and meta-analysis

Schistosomiasis is a parasitic disease caused by helminths of the genus Schistosoma with two presentations; one intestinal and another urinary; which depend on the specie of Schistosoma. One of the species that can produce intestinal schistosomiasis is Schistosoma mansoni, and the specie that produces urinary schistosomiasis is Schistosoma haematobium. Infection can be aggravated by a deficient nutritional status, which negatively impacts the immune system and increases susceptibility to infection. The main objective of this meta-analysis is to determine if a relationship exists between multimicronutrient supplementation and the reduction of infestation with Schistosoma mansoni and Schistosoma haematobium in children and adolescents. A search was conducted through a scientific literature database, and articles that complied with the pre-established requirements were retrieved. The Review Manager (Rev Man) 5.3 computer program was used for data processing and analysis was carried out with the objective of testing whether the addition of micronutrient supplementation to treatment with broad-spectrum antiparasitic anthelmintic medication has an impact on schistosomiasis infection. Of the 257 initial articles retrieved, eight were included both quantitatively and qualitatively in the meta-analysis. Supplementation reduces infestation with Schistosoma spp 1.33 times more than placebo. In individuals infested with Schistosoma, mansoni supplementation is 1.30 times more effective than placebo and for individuals infested with Schistosoma haematobium, supplementation is 1.62 times more effective than the placebo. The results show a clear relationship between supplementation and reduction of infestation. The supplementation with micronutrients decreases the presence of Schistosoma spp in children and adolescents.

Oral iron supplements for children in malaria-endemic areas

BACKGROUND

Iron-deficiency anaemia is common during childhood. Iron administration has been claimed to increase the risk of malaria.

OBJECTIVES

To evaluate the effects and safety of iron supplementation, with or without folic acid, in children living in areas with hyperendemic or holoendemic malaria transmission.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library, MEDLINE (up to August 2015) and LILACS (up to February 2015). We also checked the metaRegister of Controlled Trials (mRCT) and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) up to February 2015. We contacted the primary investigators of all included trials, ongoing trials, and those awaiting assessment to ask for unpublished data and further trials. We scanned references of included trials, pertinent reviews, and previous meta-analyses for additional references.

SELECTION CRITERIA

We included individually randomized controlled trials (RCTs) and cluster RCTs conducted in hyperendemic and holoendemic malaria regions or that reported on any malaria-related outcomes that included children younger than 18 years of age. We included trials that compared orally administered iron, iron with folic acid, and iron with antimalarial treatment versus placebo or no treatment. We included trials of iron supplementation or fortification interventions if they provided at least 80% of the Recommended Dietary Allowance (RDA) for prevention of anaemia by age. Antihelminthics could be administered to either group, and micronutrients had to be administered equally to both groups.

DATA COLLECTION AND ANALYSIS

The primary outcomes were clinical malaria, severe malaria, and death from any cause. We assessed the risk of bias in included trials with domain-based evaluation and assessed the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. We performed a fixed-effect meta-analysis for all outcomes and random-effects meta-analysis for hematological outcomes, and adjusted analyses for cluster RCTs. We based the subgroup analyses for anaemia at baseline, age, and malaria prevention or management services on trial-level data.

MAIN RESULTS

Thirty-five trials (31,955 children) met the inclusion criteria. Overall, iron does not cause an excess of clinical malaria (risk ratio (RR) 0.93, 95% confidence intervals (CI) 0.87 to 1.00; 14 trials, 7168 children, high quality evidence). Iron probably does not cause an excess of clinical malaria in both populations where anaemia is common and those in which anaemia is uncommon. In areas where there are prevention and management services for malaria, iron (with or without folic acid) may reduce clinical malaria (RR 0.91, 95% CI 0.84 to 0.97; seven trials, 5586 participants, low quality evidence), while in areas where such services are unavailable, iron (with or without folic acid) may increase the incidence of malaria, although the lower CIs indicate no difference (RR 1.16, 95% CI 1.02 to 1.31; nine trials, 19,086 participants, low quality evidence). Iron supplementation does not cause an excess of severe malaria (RR 0.90, 95% CI 0.81 to 0.98; 6 trials, 3421 children, high quality evidence). We did not observe any differences for deaths (control event rate 1%, low quality evidence). Iron and antimalarial treatment reduced clinical malaria (RR 0.54, 95% CI 0.43 to 0.67; three trials, 728 children, high quality evidence). Overall, iron resulted in fewer anaemic children at follow up, and the end average change in haemoglobin from base line was higher with iron.

AUTHORS' CONCLUSIONS

Iron treatment does not increase the risk of clinical malaria when regular malaria prevention or management services are provided. Where resources are limited, iron can be administered without screening for anaemia or for iron deficiency, as long as malaria prevention or management services are provided efficiently.

Drugs for treating urinary schistosomiasis

BACKGROUND

Urinary schistosomiasis is caused by an intravascular infection with parasitic Schistosoma haematobium worms. The adult worms typically migrate to the venous plexus of the human bladder and excrete eggs which the infected person passes in their urine. Chronic infection can cause substantial morbidity and long-term complications as the eggs become trapped in human tissues causing inflammation and fibrosis. We summarised evidence of drugs active against the infection. This is new edition of a review first published in 1997.

OBJECTIVES

To evaluate the efficacy and safety of drugs for treating urinary schistosomiasis.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, CENTRAL, EMBASE and LILACS and reference lists of articles up to 23 May 2014.

SELECTION CRITERIA

Randomized controlled trials (RCTs) of antischistosomal drugs and drug combinations compared to placebo, no intervention, or each other.

DATA COLLECTION AND ANALYSIS

Two researchers independently screened the records, extracted the data and assessed risk of bias. The primary efficacy outcomes were parasitological failure (defined as the continued presence of S. haematobium eggs in the urine at time points greater than one month after treatment), and percent reduction of egg counts from baseline. We presented dichotomous data as risk ratios (RR), and continuous data as mean difference (MD), alongside their 95% confidence intervals (CIs). Where appropriate we combined trials in meta analyses or tables. We assessed the quality of evidence using the GRADE approach.

MAIN RESULTS

We included 30 RCTs enrolling 8165 participants in this review. Twenty-four trials were conducted in children in sub-Saharan Africa, and 21 trials were over 20 years old. Many studies were assessed as being at unclear risk of bias due to inadequate descriptions of study methods. PraziquantelOn average, a single 40 mg/kg dose of praziquantel reduced the proportion of people still excreting eggs in their urine by around 60% compared to placebo at one to two months after treatment (treatment failure: RR 0.42, 95% CI 0.29 to 0.59, 864 participants, seven trials, high quality evidence). The proportion of people cured with praziquantel varied substantially between trials, from 22.5% to 83.3%, but was higher than 60% in five of the seven trials. At one to two months following praziquantel treatment at 40 mg/kg, the mean number of schistosome eggs in the urine was reduced by over 95% in five out of six trials (678 participants, six trials, high quality evidence).Splitting praziquantel 40 mg/kg into two doses over 12 hours probably has no benefits over a single dose, and in a single trial of 220 participants the split dose caused more vomiting (RR 0.5, 95% CI 0.29 to 0.86) and dizziness (RR 0.39, 95% CI 0.16 to 0.94). MetrifonateA single dose of metrifonate 10 mg/kg reduced egg excretion (210 participants, one trial, at eight months), but was only marginally better than placebo at achieving cure at one month (RR 0.83, 95% CI 0.74 to 0.94, 142 participants, one trial). In a single trial comparing one, two and three doses, the absolute number of participants cured improved from 47% after one dose to 81% after three doses (93 participants, one trial, low quality evidence).Two small trials compared 40 mg/kg single dose praziquantel with two or three doses of 10 mg/kg metrifonate and found no clear evidence of differences in cure (metrifonate 2 x 10 mg/kg at one month: RR 1.03, 95% CI 0.8 to 1.34, 72 participants, one trial; metrifonate 3 x 10 mg/kg at three months: RR 0.33, 95% CI 0.07 to 1.57, 100 participants, one trial. In one trial both drugs performed badly and in one trial both performed well. Other drugsThree trials have evaluated the antimalarial artesunate; with inconsistent results. Substantial antischistosomal effects were only seen in one of the three trials, which was at unclear risk of bias due to poor reporting of the trial methods. Similarly, another anti-malarial mefloquine has been evaluated in two small trials with inconsistent effects.Adverse events were described as mild for all evaluated drugs, but adverse event monitoring and reporting was generally of low quality.

AUTHORS' CONCLUSIONS

Praziquantel 40 mg/kg is the most studied drug for treating urinary schistosomiasis, and has the strongest evidence base.Potential strategies to improve future treatments for schistosomiasis include the combination of praziquantel with metrifonate, or with antimalarial drugs with antischistosomal properties such as artesunate and mefloquine. Evaluation of these combinations requires rigorous, adequately powered trials using standardized outcome measures.

Intermittent iron supplementation for improving nutrition and development in children under 12 years of age

BACKGROUND

Approximately 600 million children of preschool and school age are anaemic worldwide. It is estimated that half of the cases are due to iron deficiency. Consequences of iron deficiency anaemia during childhood include growth retardation, reduced school achievement, impaired motor and cognitive development, and increased morbidity and mortality. The provision of daily iron supplements is a widely used strategy for improving iron status in children but its effectiveness has been limited due to its side effects, which can include nausea, constipation or staining of the teeth. As a consequence, intermittent iron supplementation (one, two or three times a week on non-consecutive days) has been proposed as an effective and safer alternative to daily supplementation.

OBJECTIVES

To assess the effects of intermittent iron supplementation, alone or in combination with other vitamins and minerals, on nutritional and developmental outcomes in children from birth to 12 years of age compared with a placebo, no intervention or daily supplementation.

SEARCH METHODS

We searched the following databases on 24 May 2011: CENTRAL (2011, Issue 2), MEDLINE (1948 to May week 2, 2011), EMBASE (1980 to 2011 Week 20), CINAHL (1937 to current), POPLINE (all available years) and WHO International Clinical Trials Registry Platform (ICTRP). On 29 June 2011 we searched all available years in the following databases: SCIELO, LILACS, IBECS and IMBIOMED. We also contacted relevant organisations (on 3 July 2011) to identify ongoing and unpublished studies.

SELECTION CRITERIA

Randomised and quasi-randomised trials with either individual or cluster randomisation. Participants were children under the age of 12 years at the time of intervention with no specific health problems. The intervention assessed was intermittent iron supplementation compared with a placebo, no intervention or daily supplementation.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the eligibility of studies against the inclusion criteria, extracted data from included studies and assessed the risk of bias of the included studies.

MAIN RESULTS

We included 33 trials, involving 13,114 children (˜49% females) from 20 countries in Latin America, Africa and Asia. The methodological quality of the trials was mixed.Nineteen trials evaluated intermittent iron supplementation versus no intervention or a placebo and 21 studies evaluated intermittent versus daily iron supplementation. Some of these trials contributed data to both comparisons. Iron alone was provided in most of the trials.Fifteen studies included children younger than 60 months; 11 trials included children 60 months and older, and seven studies included children in both age categories. One trial included exclusively females. Seven trials included only anaemic children; three studies assessed only non-anaemic children, and in the rest the baseline prevalence of anaemia ranged from 15% to 90%.In comparison with receiving no intervention or a placebo, children receiving iron supplements intermittently have a lower risk of anaemia (average risk ratio (RR) 0.51, 95% confidence interval (CI) 0.37 to 0.72, ten studies) and iron deficiency (RR 0.24, 95% CI 0.06 to 0.91, three studies) and have higher haemoglobin (mean difference (MD) 5.20 g/L, 95% CI 2.51 to 7.88, 19 studies) and ferritin concentrations (MD 14.17 µg/L, 95% CI 3.53 to 24.81, five studies).Intermittent supplementation was as effective as daily supplementation in improving haemoglobin (MD -0.60 g/L, 95% CI -1.54 to 0.35, 19 studies) and ferritin concentrations (MD -4.19 µg/L, 95% CI -9.42 to 1.05, 10 studies), but increased the risk of anaemia in comparison with daily iron supplementation (RR 1.23, 95% CI 1.04 to1.47, six studies). Data on adherence were scarce and it tended to be higher among those children receiving intermittent supplementation, although this result was not statistically significant.We did not identify any differential effect of the type of intermittent supplementation regimen (one, two or three times a week), the total weekly dose of elemental iron, the nutrient composition, whether recipients were male or female or the length of the intervention.

AUTHORS' CONCLUSIONS

Intermittent iron supplementation is efficacious to improve haemoglobin concentrations and reduce the risk of having anaemia or iron deficiency in children younger than 12 years of age when compared with a placebo or no intervention, but it is less effective than daily supplementation to prevent or control anaemia. Intermittent supplementation may be a viable public health intervention in settings where daily supplementation has failed or has not been implemented. Information on mortality, morbidity, developmental outcomes and side effects, however, is still lacking.

Oral iron supplements for children in malaria-endemic areas

BACKGROUND

Iron-deficiency anaemia is common during childhood. Iron supplementation has been claimed to increase the risk of malaria.

OBJECTIVES

To assess the effect of iron on malaria and deaths.

SEARCH STRATEGY

We searched The Cochrane Library, PUBMED, MEDLINE, LILACS; and trial registry databases, all up to June 2011. We scanned references of included trials.

SELECTION CRITERIA

Individually and cluster randomized controlled trials conducted in hypoendemic to holoendemic malaria regions and including children below 18 years of age. We included trials comparing orally administered iron, iron with antimalarial treatment, or iron with folic acid versus placebo or no treatment. Iron fortification was excluded. Antihelminthics could be administered to either group. Additional micronutrients had to be administered equally to both groups.

DATA COLLECTION AND ANALYSIS

The primary outcomes were clinical (symptomatic) malaria, severe malaria, and death. Two authors independently selected the studies and extracted the data. We assessed heterogeneity and conducted subgroup analyses by the presence of anaemia at baseline, age, and malaria endemicity. We assessed risk of bias using domain-based evaluation. We performed a fixed-effect meta-analysis for all outcomes and random-effects meta-analysis for hematological outcomes. We adjusted analyses for cluster randomized trials.

MAIN RESULTS

Seventy-one trials (45,353 children) were included. For clinical malaria, no significant difference between iron alone and placebo was detected, (risk ratio (RR) 0.99, 95% confidence intervals (CI) 0.90 to 1.09, 13 trials). The results were similar in the subgroups of non-anaemic children and children below 2 years of age. There was no significant difference in deaths in hyper- and holoendemic areas, risk difference +1.93 per 1000 children (95% CI -1.78 to 5.64, 13 trials, 17,898 children). Iron administered for treatment of anaemia resulted in a larger increase in haemoglobin than iron given for prevention, and the benefit was similar in hyper- or holoendemic and lower endemicity settings. Iron and folic acid supplementation resulted in mixed results for severe malaria. Overall, the risk for clinical malaria was higher with iron or with iron plus folic acid in trials where services did not provide for malaria surveillance and treatment. Iron with antimalarial treatment significantly reduced malaria. Iron supplementation during an acute attack of malaria did not increase the risk for parasitological failure, (RR 0.96, 95% CI 0.74 to 1.24, three trials) or deaths.

AUTHORS' CONCLUSIONS

Iron alone or with antimalaria treatment does not increase the risk of clinical malaria or death when regular malaria surveillance and treatment services are provided. There is no need to screen for anaemia prior to iron supplementation.

Anaemia in Ugandan preschool-aged children: the relative contribution of intestinal parasites and malaria

Anaemia is a severe public health issue among African preschool-aged children, yet little effective progress has been made towards its amelioration, in part due to difficulties in unravelling its complex, multifactorial aetiology. To determine the current anaemia situation and assess the relative contribution of malaria, intestinal schistosomiasis and infection with soil-transmitted helminths, two separate cross-sectional epidemiological surveys were carried out in Uganda including 573 and 455 preschool-aged children (≤6 years) living along the shores of Lake Albert and on the islands in Lake Victoria, respectively. Anaemia was found to be a severe public health problem in Lake Albert, affecting 68·9% of children (ninety-five percent confidence intervals (95% CI) 64·9-72·7%), a statistically significant higher prevalence relative to the 27·3% detected in Lake Victoria (95% CI: 23·3-31·7%). After multivariate analysis (controlling for sex and age of the child), the only factor found to be significantly associated with increased odds of anaemia in both lake systems was malaria (Lake Albert, odds ratio (OR)=2·1, 95% CI: 1·4-3·2; Lake Victoria, OR=1·9, 95% CI: 1·2-2·9). Thus intervention strategies primarily focusing on very young children and combating malaria appear to represent the most appropriate use of human and financial resources for the prevention of anaemia in this age group and area. Looking to the future, these activities could be further emphasised within the National Child Health Days(PLUS) agenda.