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Gao Y, Wang Y, Zou S, Mi X, Kc A, Zhou H. Association of iron supplementation and deworming with early childhood development: analysis of Demographic and Health Surveys in ten low- and middle-income countries. Eur J Nutr 2021; 60:3119-3130. [PMID: 33521887 DOI: 10.1007/s00394-021-02493-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 01/13/2021] [Indexed: 10/22/2022]
Abstract
PURPOSE We assessed the associations of iron supplementation and deworming separately or combined with improved early childhood development (ECD) status. METHODS Cross-sectional data were analyzed for 29,729 children aged 36-59 months surveyed using the Demographic and Health Surveys in ten low- and middle-income countries, where iron supplementation and deworming are recommended by the World Health Organization. In each country, we estimated linear regression models for the effects of iron supplementation and deworming individually or combined on the Early Childhood Development Index (ECDI) z score, and whether this association differed between various ECD domains and the sex and residence of the child. Estimates were pooled using random-effects meta-analyses. RESULTS Compared with receiving neither of the two interventions, iron supplementation plus deworming was associated with an increased ECDI z score (β = 0.13, 95% confidence interval (CI) 0.03-0.22, p = 0.009), particularly in rural residences. However, iron supplementation and deworming, individually, were not associated with the ECDI z score. Iron supplementation plus deworming was associated with higher odds of on-track development in literacy-numeracy (OR = 1.57, 95% CI 1.24-2.01, p < 0.001) and learning domains (OR = 1.27, 95% CI 1.09-1.48, p = 0.003), but not with development in the social-emotional and physical domains. CONCLUSION Iron supplementation plus deworming, particularly for populations who are more susceptible to iron deficiency and intestinal worm infections, could be an important intervention for improving ECD. These findings may inform the argument for the necessity of implementing iron supplementation and deworming for preschool-age children.
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Affiliation(s)
- Yaqing Gao
- Department of Maternal and Child Health, School of Public Health/National Health Commission Key Laboratory of Reproductive Health, Peking University, Beijing, China
| | - Yinping Wang
- Department of Maternal and Child Health, School of Public Health/National Health Commission Key Laboratory of Reproductive Health, Peking University, Beijing, China
| | - Siyu Zou
- Department of Maternal and Child Health, School of Public Health/National Health Commission Key Laboratory of Reproductive Health, Peking University, Beijing, China
| | - Xiaoyi Mi
- Department of Maternal and Child Health, School of Public Health/National Health Commission Key Laboratory of Reproductive Health, Peking University, Beijing, China
| | - Ashish Kc
- International Maternal and Child Health, Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
| | - Hong Zhou
- Department of Maternal and Child Health, School of Public Health/National Health Commission Key Laboratory of Reproductive Health, Peking University, Beijing, China.
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Mazibuko XI, Chimbari MJ. Parasitic infections and environmental influences on verbal memory and learning potential of isiZulu speaking pre-school children. JOURNAL OF PSYCHOLOGY IN AFRICA 2020. [DOI: 10.1080/14330237.2020.1821318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Xolisile I. Mazibuko
- School of Nursing & Public Health, University of KwaZulu-Natal, Durban, South Africa
| | - Moses J. Chimbari
- School of Nursing & Public Health, University of KwaZulu-Natal, Durban, South Africa
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Bayesian Methods for Exposure Misclassification Adjustment in a Mediation Analysis: Hemoglobin and Malnutrition in the Association Between Ascaris and IQ. Epidemiology 2019; 30:659-668. [PMID: 31205289 DOI: 10.1097/ede.0000000000001051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
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.
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Blouin B, Casapía M, Joseph L, Kaufman JS, Larson C, Gyorkos TW. The effect of cumulative soil-transmitted helminth infections over time on child development: a 4-year longitudinal cohort study in preschool children using Bayesian methods to adjust for exposure misclassification. Int J Epidemiol 2018; 47:1180-1194. [PMID: 30010794 PMCID: PMC6124617 DOI: 10.1093/ije/dyy142] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2018] [Indexed: 11/12/2022] Open
Abstract
Background Limited research has documented an association between soil-transmitted helminth (STH) infections and child development. This has recently been identified as an important knowledge gap. Methods A longitudinal cohort study was conducted in Iquitos, Peru, between September 2011 and July 2016. A cohort of 880 children, recruited at 1 year of age, was followed up to 5 years. STH infection was measured annually and child development was measured with the Wechsler Preschool and Primary Scale of Intelligence III (WPPSI-III) at 5 years. Linear-regression models were used to investigate the effect of the number of detected STH infections between 1 and 5 years of age on WPPSI-III scores at 5 years of age. Bayesian latent class analysis was used to adjust for exposure misclassification. Results A total of 781 (88.8%) children were included in the analysis. In multivariable analysis, adjusted for STH misclassification, increasing numbers of Ascaris, Trichuris, hookworm and any STH infections were associated with lower WPPSI-III scores. Among the largest observed effects were those for the effect of Ascaris infection on verbal IQ scores [difference in IQ (95% CrI) for two, three, and four or five detected infections compared with zero or one infection: -8.27 (-13.85, -3.10), -6.69 (-12.05, -2.05) and -5.06 (-10.75, 0.05), respectively]. Misclassification of STH infection generally led to a bias towards the null. Conclusions These results document an association between STH infection and child development. The results highlight the importance of adjusting for STH misclassification; however, future research is needed to accurately determine the sensitivity of STH diagnostic techniques. STH control in preschool children may contribute to lowering the disease burden associated with poor child development.
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Affiliation(s)
- Brittany Blouin
- Division of Clinical Epidemiology, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada
| | | | - Lawrence Joseph
- Division of Clinical Epidemiology, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Jay S Kaufman
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Charles Larson
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Theresa W Gyorkos
- Division of Clinical Epidemiology, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada
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Owada K, Nielsen M, Lau CL, Clements ACA, Yakob L, Soares Magalhães RJ. Measuring the Effect of Soil-Transmitted Helminth Infections on Cognitive Function in Children: Systematic Review and Critical Appraisal of Evidence. ADVANCES IN PARASITOLOGY 2017; 98:1-37. [PMID: 28942767 DOI: 10.1016/bs.apar.2017.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Recently the role of soil-transmitted helminth (STH) infections in children's cognitive developmental impairment has been under scrutiny. We conducted a systematic review of the evidence for associations between STH infections and cognitive function of children using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. We aimed to identify the domains of cognitive function in three age strata (<24months, 24-59months and ≥60months) and critically appraise the general design protocol of the studies, with a focus on the cognitive function measurement tools used. A total of 42 papers fulfilled the inclusion criteria, including 10 studies from a recent Cochrane review. Our findings demonstrate variation in tested domains, lack of consistency in the use of measurement tools and analysis of results. Cognitive function measures in children aged under 59months have been mainly limited to domains of gross motor, fine motor and language skills, whereas in children aged 60months and above most studies tested domains such as memory and processing speed. Even within the same age group the results on the association between STH infections and measures of cognitive development were often conflicting. The current study highlights the need for methodological consensus in the use of measurement tools and data analysis protocols if the effect of STH infections on cognitive function domains in children is to be correctly established. This will be an imperative next step to generate conclusive evidence of the role of STH infections in cognitive development in children.
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Affiliation(s)
- Kei Owada
- School of Medicine, The University of Queensland, South Brisbane, QLD, Australia; Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane, QLD, Australia
| | - Mark Nielsen
- School of Psychology, The University of Queensland, St Lucia, QLD, Australia; Faculty of Humanities, University of Johannesburg, Auckland Park, South Africa
| | - Colleen L Lau
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, ACT, Australia; Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane, QLD, Australia
| | - Archie C A Clements
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, ACT, Australia
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ricardo J Soares Magalhães
- Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia; Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, South Brisbane, QLD, Australia
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Guernier V, Brennan B, Yakob L, Milinovich G, Clements ACA, Soares Magalhaes RJ. Gut microbiota disturbance during helminth infection: can it affect cognition and behaviour of children? BMC Infect Dis 2017; 17:58. [PMID: 28073356 PMCID: PMC5225537 DOI: 10.1186/s12879-016-2146-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 12/21/2016] [Indexed: 12/26/2022] Open
Abstract
Background Bidirectional signalling between the brain and the gastrointestinal tract is regulated at neural, hormonal, and immunological levels. Recent studies have shown that helminth infections can alter the normal gut microbiota. Studies have also shown that the gut microbiota is instrumental in the normal development, maturation and function of the brain. The pathophysiological pathways by which helminth infections contribute to altered cognitive function remain poorly understood. Discussion We put forward the hypothesis that gastrointestinal infections with parasitic worms, such as helminths, induce an imbalance of the gut-brain axis, which, in turn, can detrimentally manifest in brain development. Factors supporting this hypothesis are: 1) research focusing on intelligence and school performance in school-aged children has shown helminth infections to be associated with cognitive impairment, 2) disturbances in gut microbiota have been shown to be associated with important cognitive developmental effects, and 3) helminth infections have been shown to alter the gut microbiota structure. Evidence on the complex interactions between extrinsic (parasite) and intrinsic (host-derived) factors has been synthesised and discussed. Summary While evidence in favour of the helminth-gut microbiota-central nervous system hypothesis is circumstantial, it would be unwise to rule it out as a possible mechanism by which gastrointestinal helminth infections induce childhood cognitive morbidity. Further empirical studies are necessary to test an indirect effect of helminth infections on the modulation of mood and behaviour through its effects on the gut microbiota.
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Affiliation(s)
- Vanina Guernier
- School of Veterinary Science, University of Queensland, Gatton, 4343, QLD, Australia
| | - Bradley Brennan
- School of Public Health, University of Queensland, Herston, 4006, QLD, Australia.,Princess Alexandra Hospital, Metro South Health and Hospital Services, Brisbane, Australia
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Gabriel Milinovich
- School of Public Health, University of Queensland, Herston, 4006, QLD, Australia
| | - Archie C A Clements
- Research School of Population Health, Australian National University, Canberra, Australia
| | - Ricardo J Soares Magalhaes
- School of Veterinary Science, University of Queensland, Gatton, 4343, QLD, Australia. .,Children's Health Research Centre, University of Queensland, South Brisbane, 4101, QLD, Australia.
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Joseph SA, Casapía M, Lazarte F, Rahme E, Pezo L, Blouin B, Gyorkos TW. The effect of deworming on early childhood development in Peru: A randomized controlled trial. SSM Popul Health 2015; 1:32-39. [PMID: 29349119 PMCID: PMC5757899 DOI: 10.1016/j.ssmph.2015.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 12/05/2022] Open
Abstract
Background There is a knowledge gap on the effect of early childhood deworming on development in low- and middle-income countries. This evidence is important in the critical window of growth and development before two years of age. Methods A randomized controlled trial of the benefit, and optimal timing and frequency, of deworming on development was conducted in Iquitos, Peru. Children were enrolled during routine 12-month growth and development visits and randomly allocated to: (1) deworming at the 12-month visit and placebo at the 18-month visit; (2) placebo at the 12-month visit and deworming at the 18-month visit; (3) deworming at the 12 and 18-month visits; or (4) placebo at the 12 and 18-month visits. The Bayley Scales of Infant Development III was used to assess cognitive, language and motor skills at the 12 and 24-month visits. One-way ANOVA analyses used an intention-to-treat approach. Results Between September 2011 and June 2012, 1760 children were enrolled. Attendance at the 24-month visit was 88.8% (n=1563). Raw scores on all subtests increased over 12 months; however, cognitive and expressive language scaled scores decreased. There was no statistically significant benefit of deworming, or effect of timing or frequency, on any of the development scores. Baseline height and weight and maternal education were associated with development scores at 24 months. Conclusions After 12 months of follow-up, an overall benefit of deworming on cognition, language or fine motor development was not detected. Additional integrated child and maternal interventions should be considered to prevent developmental deficits in this critical period. This is the first and largest deworming trial exclusively in 1-year-old children. We examined the effect of deworming on early childhood development. Deworming did not impact cognition, language or motor skills. Concomitant poverty and malnutrition may obscure the true effect of deworming.
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Affiliation(s)
- Serene A. Joseph
- McGill University, Department of Epidemiology, Biostatistics and Occupational Health, Montréal, Québec, Canada
- Research Institute of the McGill University Health Centre, Division of Clinical Epidemiology, Montréal, Québec, Canada
| | | | | | - Elham Rahme
- Research Institute of the McGill University Health Centre, Division of Clinical Epidemiology, Montréal, Québec, Canada
- McGill University, Department of Medicine, Montréal, Québec, Canada
| | - Lidsky Pezo
- Asociación Civil Selva Amazónica, Iquitos, Peru
| | - Brittany Blouin
- McGill University, Department of Epidemiology, Biostatistics and Occupational Health, Montréal, Québec, Canada
- Research Institute of the McGill University Health Centre, Division of Clinical Epidemiology, Montréal, Québec, Canada
| | - Theresa W. Gyorkos
- McGill University, Department of Epidemiology, Biostatistics and Occupational Health, Montréal, Québec, Canada
- Research Institute of the McGill University Health Centre, Division of Clinical Epidemiology, Montréal, Québec, Canada
- Correspondence to: Division of Clinical Epidemiology, Research Institute of the McGill University Health Centre, Royal Victoria Hospital, V Building, 687 Pine Avenue West, Montreal, QC, Canada H3A 1A1. Tel.: +1 514 934 1934x44721.
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John CC, Carabin H, Montano SM, Bangirana P, Zunt JR, Peterson PK. Global research priorities for infections that affect the nervous system. Nature 2015; 527:S178-86. [PMID: 26580325 PMCID: PMC4697933 DOI: 10.1038/nature16033] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Infections that cause significant nervous system morbidity globally include viral (for example, HIV, rabies, Japanese encephalitis virus, herpes simplex virus, varicella zoster virus, cytomegalovirus, dengue virus and chikungunya virus), bacterial (for example, tuberculosis, syphilis, bacterial meningitis and sepsis), fungal (for example, cryptococcal meningitis) and parasitic (for example, malaria, neurocysticercosis, neuroschistosomiasis and soil-transmitted helminths) infections. The neurological, cognitive, behavioural or mental health problems caused by the infections probably affect millions of children and adults in low- and middle-income countries. However, precise estimates of morbidity are lacking for most infections, and there is limited information on the pathogenesis of nervous system injury in these infections. Key research priorities for infection-related nervous system morbidity include accurate estimates of disease burden; point-of-care assays for infection diagnosis; improved tools for the assessment of neurological, cognitive and mental health impairment; vaccines and other interventions for preventing infections; improved understanding of the pathogenesis of nervous system disease in these infections; more effective methods to treat and prevent nervous system sequelae; operations research to implement known effective interventions; and improved methods of rehabilitation. Research in these areas, accompanied by efforts to implement promising technologies and therapies, could substantially decrease the morbidity and mortality of infections affecting the nervous system in low- and middle-income countries.
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Affiliation(s)
- Chandy C John
- Ryan White Center for Pediatric Infectious Disease and Global Health, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | - Hélène Carabin
- Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
| | - Silvia M Montano
- Department of Bacteriology, US Naval Medical Research Unit No. 6, Lima, Peru
| | - Paul Bangirana
- Department of Psychiatry, Makerere University College of Health Sciences, Kampala, Uganda
| | - Joseph R Zunt
- Department of Epidemiology, University of Washington, Seattle, Washington 98195, USA
| | - Phillip K Peterson
- Division of Infectious Diseases and International Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA
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