The effect of iron and multi-micronutrient supplementation on Ascaris lumbricoides reinfection among Zambian schoolchildren

Impact of weekly iron-folic acid supplementation on nutritional status and parasitic reinfection among school-age children and adolescents in Sub-Saharan Africa: a systematic review and meta-analysis

Background

Two significant etiological factors contributing to iron deficiency anemia, and undernutrition posing substantial public health challenges in Sub-Saharan Africa, are soil-transmitted helminths and malaria. This study carried out the effect of weekly iron-folic acid supplementation (WIFAS) on the nutrition and general health of school-age children and adolescents in Sub-Saharan Africa, a systematic review and meta-analysis have been conducted.

Methods

To find pertinent publications for this study, a thorough search was carried out on May 20, 2023, across five databases: Pubmed (MEDLINE), Web of Science, Scopus, Cochrane Library, and Google Scholar. In addition, a search was conducted on August 23, 2023, to capture any new records. The inclusion criteria for the studies were based on school-age children and adolescent populations, randomized controlled trials, and investigations into the effects of WIFAS. The outcomes of interest were measured through anthropometric changes, malaria, and helminthic reinfection.

Results

A systematic review of 11 articles revealed that WIFAS significantly decreased the risk of schistosomiasis reinfection by 21% among adolescents (risk ratio = 0.79, 95%CI: 0.66, 0.97; heterogeneity I 2 = 0.00%, P = 0.02). However, no significant impact was observed on the risk of malaria reinfection (risk ratio = 1.02, 95%CI: 0.92, 1.13; heterogeneity I 2 = 0.00%, P = 0.67) or A. Lumbricoides reinfection (risk ratio = 0.95, 95%CI: 0.75, 1.19; heterogeneity I 2 = 0.00%, P = 0.65). Moreover, the analysis demonstrated that there is no significant effect of iron-folic acid supplementation in measured height and height for age Z-score (HAZ) of the school-age children (Hedge's g -0.05, 95%CI: -0.3, 0.2; test for heterogeneity I 2 = 0.00%, P = 0.7) and (Hedge's g 0.12, 95%CI: -0.13, 0.37; test for heterogeneity I 2 = 0.00%, P = 0.36) respectively.

Conclusion

The effectiveness of WIFAS in reducing the risk of schistosomiasis reinfection in adolescents has been demonstrated to be greater than that of a placebo or no intervention. Additionally, the narrative synthesis of iron-folic acid supplementation has emerged as a potential public health intervention for promoting weight change. However, there was no significant association between WIFAS and Ascariasis, trichuriasis, and hookworm. Moreover, the certainty of the evidence for the effects of WIFAS on height and malaria is low and therefore inconclusive. Whereas, the certainty of the evidence for the effectiveness of WIFAS on Schistosomiasis is moderate. Even though the mechanisms need further research WIFAS may be implemented as part of a comprehensive public health strategy to address schistosomiasis in adolescents.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023397898, PROSPERO (CRD42023397898).

Neighborhood-Based Socioeconomic Determinants of Cognitive Impairment in Zambian Children With HIV: A Quantitative Geographic Information Systems Approach

BACKGROUND

Place-based inequalities, such as exposure to violence and access to nutritious food and clean water, may contribute to human immunodeficiency virus (HIV)-associated cognitive impairment. In this study, we investigated neighborhood effects on cognition in children and adolescents with HIV in Lusaka, Zambia.

METHODS

We conducted a prospective cohort study of 208 children with perinatally acquired HIV (ages 8-17) and 208 HIV-exposed uninfected controls. Participants underwent neuropsychological testing and interviews assessing socioeconomic status. Geographic regions with clusters of participants with HIV and cognitive impairment were identified using quantitative geographic information systems (QGIS) and SaTScan. Associations between location of residence and cognitive function were evaluated in bivariable and multivariable regression models. Mediation analysis was performed to assess direct and indirect effects of location of the residence on cognitive impairment.

RESULTS

Residence in Chawama, one of the poorest neighborhoods in Lusaka, was significantly associated with cognitive impairment in participants with HIV (odds ratio 2.9; P = .005) and remained significant in a multivariable regression model controlling for potential confounders. Mediation analysis found that 46% of the cognitive effects of residence in Chawama were explained by higher rates of malnutrition, lower school attendance, and poorer self-reported health.

CONCLUSIONS

Place-based socioeconomic inequality contributes to cognitive impairment in Zambian children and adolescents with HIV. Neighborhood effects may be mediated by concentrated poverty, malnutrition, limited access to education and health care, and other yet unknown environmental factors that may be potentially modifiable.

Effects of nutritional supplements on the re-infection rate of soil-transmitted helminths in school-age children: A systematic review and meta-analysis

Background

The effect of nutritional supplements on the re-infection rate of species-specific soil-transmitted helminth infections in school-aged children remains complex and available evidence on the subject matter has not been synthesized.

Methods

The review included randomised controlled trials (RCTs) and cluster RCTs investigating food supplements on school-aged children between the age of 4–17 years. A search for RCTs was conducted on eight databases from inception to 12^th June 2019. Cochrane Risk of Bias tool was used to assess the risk of bias in all included studies. Meta-analysis and narrative synthesis were conducted to describe and analyze the results of the review. Outcomes were summarized using the mean difference or standardized mean difference where appropriate.

Results

The search produced 1,816 records. Six studies met the inclusion criteria (five individually RCTs and one cluster RCT). Four studies reported data on all three STH species, while one study only reported data on Ascaris lumbricoides infections and the last study reported data on only hookworm infections. Overall, the risk of bias in four individual studies was low across most domains. Nutritional supplementation failed to statistically reduce the re-infection rates of the three STH species. The effect of nutritional supplements on measures of physical wellbeing in school-aged children could not be determined.

Conclusions

The findings from this systematic review suggest that nutritional supplements for treatment of STH in children should not be encouraged unless better evidence emerges. Conclusion of earlier reviews on general populations may not necessarily apply to children since children possibly have a higher re-infection rate.

Bayesian Methods for Exposure Misclassification Adjustment in a Mediation Analysis: Hemoglobin and Malnutrition in the Association Between Ascaris and IQ

BACKGROUND

Soil-transmitted helminth infections have been found to be associated with child development. The objective was to investigate hemoglobin levels and malnutrition as mediators of the association between Ascaris infection and intelligence quotient (IQ) scores in children.

METHODS

We conducted a longitudinal cohort study in Iquitos, Peru, between September 2011 and July 2016. A total of 1760 children were recruited at 1 year of age and followed up annually to 5 years. We measured Ascaris infection and malnutrition at each study visit, and hemoglobin levels were measured as of age 3. The exposure was defined as the number of detected Ascaris infections between age 1 and 5. We measured IQ scores at age 5 and used Bayesian models to correct exposure misclassification.

RESULTS

We included a sample of 781 children in the analysis. In results adjusted for Ascaris misclassification, mean hemoglobin levels mediated the association between Ascaris infection and IQ scores. The natural direct effects (not mediated by hemoglobin) (95% CrI) and natural indirect effects (mediated by hemoglobin) (95% CrI) were compared with no or one infection: -0.9 (-4.6, 2.8) and -4.3 (-6.9, -1.6) for the effect of two infections; -1.4 (-3.8, 1.0) and -1.2 (-2.0, -0.4) for three infections; and -0.4 (-3.2, 2.4) and -2.7 (-4.3, -1.0) for four or five infections.

CONCLUSION

Our results are consistent with the hypothesis that hemoglobin levels mediate the association between Ascaris infection and IQ scores. Additional research investigating the effect of including iron supplements in STH control programs is warranted.

Fortification of Carica papaya fruit seeds to school meal snacks may aid Africa mass deworming programs: a preliminary survey

BACKGROUND

Soil transmitted helminths (STHs) are among the world's neglected tropical diseases. Morbidity due to STHs is greatest in school-age children who typically have the highest burden of infection. In 2001, WHO passed a resolution for the use of large-scale mass drug administration (MDA) to deworm vulnerable children through school based programs. Though effective, there is concern that MDA might not be sustainable over extended periods. Additionally the current MDA strategy does not consider child malnutrition, a very common malady in resource limited countries. We report a pilot evaluation of an innovation that bundles school feeding and deworming.

METHODS

We designed a maize (corn) flour fortified with grounded dried papaya (Carica papaya) seeds and used it to prepare porridge as per the usual school meal recipe Children from three primary schools from Nandi County in Kenya were randomized into three arms: One school received 300 ml papaya fortified porridge daily (papaya group), the second school received similar serving of plain porridge without the pawpaw ingredient (control group) and the third school received plain porridge and the conventional MDA approach of one time 400 mg dosage of albendazole (albendazole arm). Prior to the randomization, an initial baseline stool microscopy analysis was done to determine presence and intensity of intestinal worms. Core indicators of nutrition-height, weight and hemoglobin counts were also assessed. The children were monitored daily for two months and final stool sample analysis and clinical monitoring done at the end of the study. Baseline and follow-up data were analyzed and compared through SAS version 9.1 statistical package.

RESULTS

A total of 326 children participated in the trial. The overall prevalence of Ascaris lumbricoides was 29.4% (96), Trichuris Trichura 5.2% (17) and hookworm 1 (0.3%). Papaya seed fortified porridge reduced the Ascaris lumbricoides egg count by 63.9% after the two month period (mean 209.7epg to 75.7 p < 0.002) as compared to the albendazole arm 78.8% (129.5 epg to 27.5, p value 0.006). The control group showed an increase in egg count (42.epg to 56.3) though it was not statistically significant. Hemoglobin counts in the papaya group increased from a mean of 2 g/dL (11.5 g/dL to 13.5 g/dL, p < 0.001), as compared to the albendazole arm that increased by 1 g/dL (12.8-13.9, p < 0.001). No significant change was observed in the placebo arm (13.2 to 13.1). Interestingly the papaya group showed a significant reduction of children with Tinea capitis (ringworms) (54.4 to 34%, p < 0.002) as compared to the albendazole arm that showed an increase in ringworm infestation though not statistically significant (39.7 to 64.7% p = 0.608).

CONCLUSION

Papaya seed fortified porridge had a significant effect on reduction of Ascaris lumbricoides burden. It had a better nutritional outcome and effect on child fungal infections than albendazole. Its application as a routine school meal may aid current national school based nutrition and deworming programs in Africa.

TRIAL REGISTRATION

This study was retrospectively registered at Clinicaltrials.gov Ref. NCT02725255 on 31st March 2016.

Soil-Transmitted Helminth Reinfection and Associated Risk Factors among School-Age Children in Chencha District, Southern Ethiopia: A Cross-Sectional Study

Mass drug administration (MDA) to the most risky population including school-age children (SAC) is the central strategy to control soil-transmitted helminth (STH) infection. The present study was aimed at estimating the prevalence of STHs reinfection three months posttreatment and associated risk factors among SAC in Chencha district. A cross-sectional study design was employed from April 20 to May 5, 2015, to enroll 408 SAC. Structured questionnaire and Kato-Katz thick smear technique were used to interview parents or guardians and quantify the number of eggs per gram of stool. Pearson chi-square and logistic regression were used to assess the association between predictor variable and STH reinfection. The prevalence of STHs within three months of mass chemotherapy among SAC was 36.8% which is 93.4% of the prevalence (39.4%) before treatment. The estimated prevalence of reinfection (95%CI) for Ascaris lumbricoides, Trichuris trichiura, and hookworms was 23.8% (21.1–28.2), 16.2% (12.7–20.1), and 1.0% (0.3–2.5), respectively. Children of merchant fathers were more likely to be reinfected by STHs in Chencha district. In conclusion, there is rapid reinfection after mass chemotherapy among SAC in Chencha district. Further studies should be carried out to generate cost efficient methods that can supplement mass drug administration to accelerate the control of STHs.

Helminth infections and micronutrients in school-age children: a systematic review and meta-analysis

BACKGROUND

Helminth infections and micronutrient deficiencies are highly prevalent in developing countries. Neither condition typically causes overt disease, but they do lead to indirect morbidity such as impaired physical and cognitive development.

OBJECTIVE

We aimed to systematically review current evidence on the relation of helminth infections with micronutrient status in school-age children worldwide.

DESIGN

We included both observational studies and randomized controlled trials (RCTs). We applied a random-effects meta-analysis to estimate 1) cross-sectional associations between helminths and micronutrient status, 2) effects of anthelminthic treatment on micronutrient status, and 3) effects of micronutrient supplementation on helminth infection and reinfection.

RESULTS

Meta-analyses of observational studies showed an association between helminth infections and serum retinol [standardized mean difference (SMD): -0.30; 95% CI: -0.48, -0.13] but not serum ferritin (SMD: 0.00; 95% CI: -0.7, 0.7). Conversely, meta-analyses of anthelminthic treatment RCTs showed a positive effect on ferritin (SMD: 0.16; 95% CI: 0.09, 0.22) but not retinol (SMD: 0.04; 95% CI: -0.06, 0.14). The number of studies on micronutrients other than ferritin and retinol was not sufficient for pooling. Meta-analyses of micronutrient-supplementation RCTs showed only a modest protective effect for multimicronutrient interventions on helminth infection and reinfection rates (OR: 0.77; 95% CI: 0.61, 0.97).

CONCLUSIONS

In this review, we show evidence of distinct associations between helminth infections and micronutrients in school-age children. More studies are needed on micronutrients other than iron and vitamin A and on possible helminth species-specific effects. A thorough comprehension of the interplay between helminth infections and micronutrients will help guide integrated and sustainable intervention strategies in affected children worldwide.

Influence of nutrition on infection and re-infection with soil-transmitted helminths: a systematic review

Background

The relationship between nutrition and soil-transmitted helminthiasis is complex and warrants further investigation. We conducted a systematic review examining the influence of nutrition on infection and re-infection with soil-transmitted helminths (i.e. Ascaris lumbricoides, hookworm, Trichuris trichiura and Strongyloides stercoralis) in humans. Emphasis was placed on the use of nutritional supplementation, alongside anthelminthic treatment, to prevent re-infection with soil-transmitted helminths.

Methods

We searched eight electronic databases from inception to 31 July 2013, with no restriction of language or type of publication. For studies that met our inclusion criteria, we extracted information on the soil-transmitted helminth species, nutritional supplementation and anthelminthic treatment. Outcomes were presented in forest plots and a summary of findings (SoF) table. An evidence profile (EP) was generated by rating the evidence quality of the identified studies according to the GRADE system.

Results

Fifteen studies met our inclusion criteria; eight randomised controlled trials and seven prospective cohort studies. Data on A. lumbricoides were available from all studies, whereas seven and six studies additionally contained data on T. trichiura and hookworm, respectively. None of the studies contained data on S. stercoralis. Positive effects of nutritional supplementation or the host’s natural nutritional status on (re-)infection with soil-transmitted helminths were reported in 14 studies, while negative effects were documented in six studies. In terms of quality, a high, low and very low quality rating was assigned to the evidence from four, six and five studies, respectively.

Conclusions

Our findings suggest that the current evidence-base is weak, precluding guidelines on nutrition management as a potential supplementary tool to preventive chemotherapy targeting soil-transmitted helminthiasis. Moreover, several epidemiological, immunological and methodological issues have been identified, and these should be considered when designing future studies.

Effects of daily iron supplementation in primary-school-aged children: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Anemia is an important public health and clinical problem. Observational studies have linked iron deficiency and anemia in children with many poor outcomes, including impaired cognitive development; however, iron supplementation, a widely used preventive and therapeutic strategy, is associated with adverse effects. Primary-school-aged children are at a critical stage in intellectual development, and optimization of their cognitive performance could have long-lasting individual and population benefits. In this study, we summarize the evidence for the benefits and safety of daily iron supplementation in primary-school-aged children.

METHODS

We searched electronic databases (including MEDLINE and Embase) and other sources (July 2013) for randomized and quasi-randomized controlled trials involving daily iron supplementation in children aged 5-12 years. We combined the data using random effects meta-analysis.

RESULTS

We identified 16 501 studies; of these, we evaluated 76 full-text papers and included 32 studies including 7089 children. Of the included studies, 31 were conducted in low- or middle-income settings. Iron supplementation improved global cognitive scores (standardized mean difference 0.50, 95% confidence interval [CI] 0.11 to 0.90, p = 0.01), intelligence quotient among anemic children (mean difference 4.55, 95% CI 0.16 to 8.94, p = 0.04) and measures of attention and concentration. Iron supplementation also improved age-adjusted height among all children and age-adjusted weight among anemic children. Iron supplementation reduced the risk of anemia by 50% and the risk of iron deficiency by 79%. Adherence in the trial settings was generally high. Safety data were limited.

INTERPRETATION

Our analysis suggests that iron supplementation safely improves hematologic and nonhematologic outcomes among primary-school-aged children in low- or middle-income settings and is well-tolerated.

Soil-transmitted helminth reinfection after drug treatment: a systematic review and meta-analysis

Background

Soil-transmitted helminth (STH) infections (i.e., Ascaris lumbricoides, hookworm, and Trichuris trichiura) affect more than a billion people. Preventive chemotherapy (i.e., repeated administration of anthelmintic drugs to at-risk populations), is the mainstay of control. This strategy, however, does not prevent reinfection. We performed a systematic review and meta-analysis to assess patterns and dynamics of STH reinfection after drug treatment.

Methodology

We systematically searched PubMed, ISI Web of Science, EMBASE, Cochrane Database of Systematic Reviews, China National Knowledge Infrastructure, WanFang Database, Chinese Scientific Journal Database, and Google Scholar. Information on study year, country, sample size, age of participants, diagnostic method, drug administration strategy, prevalence and intensity of infection pre- and posttreatment, cure and egg reduction rate, evaluation period posttreatment, and adherence was extracted. Pooled risk ratios from random-effects models were used to assess the risk of STH reinfection after treatment. Our protocol is available on PROSPERO, registration number: CRD42011001678.

Principal Findings

From 154 studies identified, 51 were included and 24 provided STH infection rates pre- and posttreatment, whereas 42 reported determinants of predisposition to reinfection. At 3, 6, and 12 months posttreatment, A. lumbricoides prevalence reached 26% (95% confidence interval (CI): 16–43%), 68% (95% CI: 60–76%) and 94% (95% CI: 88–100%) of pretreatment levels, respectively. For T. trichiura, respective reinfection prevalence were 36% (95% CI: 28–47%), 67% (95% CI: 42–100%), and 82% (95% CI: 62–100%), and for hookworm, 30% (95% CI: 26–34%), 55% (95% CI: 34–87%), and 57% (95% CI: 49–67%). Prevalence and intensity of reinfection were positively correlated with pretreatment infection status.

Conclusion

STH reinfections occur rapidly after treatment, particularly for A. lumbricoides and T. trichiura. Hence, there is a need for frequent anthelmintic drug administrations to maximize the benefit of preventive chemotherapy. Integrated control approaches emphasizing health education and environmental sanitation are needed to interrupt transmission of STH.

Infections with soil-transmitted helminths (the roundworm Ascaris lumbricoides, the whipworm Trichuris trichiura, and hookworm) affect over 1 billion people, particularly rural communities in the developing world. The global strategy to control soil-transmitted helminth infections is ‘preventive chemotherapy’, which means large-scale administration of anthelmintic drugs to at-risk populations. However, because reinfection occurs after treatment, ‘preventive chemotherapy’ must be repeated regularly. Our systematic review and meta-analysis found that at 3, 6, and 12 months after treatment, A. lumbricoides prevalence reached 26% (95% confidence interval (CI): 16–43%), 68% (95% CI: 60–76%) and 94% (95% CI: 88–100%) of pretreatment levels, respectively. For T. trichiura, respective reinfection prevalence at these time points were 36% (95% CI: 28–47%), 67% (95% CI: 42–100%), and 82% (95% CI: 62–100%); and for hookworm, 30% (95% CI: 26–34%), 55% (95% CI: 34–87%), and 57% (95% CI: 49–67%). Prevalence and intensity of reinfection were positively correlated with pretreatment infection status. Our results suggest a frequent anthelmintic drug administration to maximize the benefit of preventive chemotherapy. Moreover, an integrated control strategy, consisting of preventive chemotherapy combined with health education and environmental sanitation is needed to interrupt transmission of soil-transmitted helminths.

Decreased parasite load and improved cognitive outcomes caused by deworming and consumption of multi-micronutrient fortified biscuits in rural Vietnamese schoolchildren

Micronutrient deficiencies are associated with impaired growth and cognitive function. A school-based fortification program might benefit schoolchildren but a high prevalence of parasite infestation might affect effectiveness. A randomized, double-blind, placebo-controlled 2 × 2 factorial trial was conducted to assess the efficacy of multi-micronutrient fortified biscuits with or without de-worming on growth, cognitive function, and parasite load in Vietnamese schoolchildren. Schoolchildren (n = 510), 6-8 years of age were randomly allocated to receive albendazole or placebo at baseline and four months of multi-micronutrient fortified biscuits (FB) or non-fortified biscuits. Children receiving FB for four months scored higher on two cognitive tests: Raven's Colored Progressive Matrices and the Digit Span Forward test. Children receiving albendazole plus FB had the lowest parasite load after four months. In children receiving FB, mid-upper arm circumference was slightly improved (+0.082 cm) but there were no differences in other indexes of anthropometry. Combining multi-micronutrient fortified biscuits with de-worming is an effective strategy.

Ingestion of micronutrient fortified breakfast cereal has no influence on immune function in healthy children: a randomized controlled trial

BACKGROUND

This study investigated the influence of 2-months ingestion of an "immune" nutrient fortified breakfast cereal on immune function and upper respiratory tract infection (URTI) in healthy children during the winter season.

METHODS

Subjects included 73 children (N=42 males, N=31 females) ranging in age from 7 to 13 years (mean±SD age, 9.9±1.7 years), and 65 completed all phases of the study. Subjects were randomized to one of three groups--low, moderate, or high fortification--with breakfast cereals administered in double blinded fashion. The "medium" fortified cereal contained B-complex vitamins, vitamins A and C, iron, zinc, and calcium, with the addition of vitamin E and higher amounts of vitamins A and C, and zinc in the "high" group. Immune measures included delayed-typed hypersensitivity, global IgG antibody response over four weeks to pneumococcal vaccination, salivary IgA concentration, natural killer cell activity, and granulocyte phagocytosis and oxidative burst activity. Subjects under parental supervision filled in a daily log using URTI symptoms codes.

RESULTS

Subjects ingested 3337±851 g cereal during the 2-month study, which represented 14% of total diet energy intake and 20-85% of selected vitamins and minerals. Despite significant increases in nutrient intake, URTI rates and pre- to- post-study changes in all immune function measures did not differ between groups.

CONCLUSIONS

Data from this study indicate that ingestion of breakfast cereal fortified with a micronutrient blend for two winter months by healthy, growing children does not significantly influence biomarkers for immune function or URTI rates.