title: Helminth infections and micronutrients in school-age children: a systematic review and meta-analysis.
abstract: 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.
  
  
  METHODS
  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.
authors.affiliation: From the Department of Health Sciences (MCP, CMD, and KP) and Section of Health and Life Sciences (BdG and MvdB), VU University Amsterdam, Amsterdam, Netherlands, and the Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium (KP).
authors.forename: Brechje
authors.initials: B
authors.lastname: de Gier
authors.affiliation: From the Department of Health Sciences (MCP, CMD, and KP) and Section of Health and Life Sciences (BdG and MvdB), VU University Amsterdam, Amsterdam, Netherlands, and the Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium (KP).
authors.forename: Maiza
authors.initials: M
authors.lastname: Campos Ponce
authors.affiliation: From the Department of Health Sciences (MCP, CMD, and KP) and Section of Health and Life Sciences (BdG and MvdB), VU University Amsterdam, Amsterdam, Netherlands, and the Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium (KP).
authors.forename: Margot
authors.initials: M
authors.lastname: van de Bor
authors.affiliation: From the Department of Health Sciences (MCP, CMD, and KP) and Section of Health and Life Sciences (BdG and MvdB), VU University Amsterdam, Amsterdam, Netherlands, and the Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium (KP).
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Doak
authors.affiliation: From the Department of Health Sciences (MCP, CMD, and KP) and Section of Health and Life Sciences (BdG and MvdB), VU University Amsterdam, Amsterdam, Netherlands, and the Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium (KP).
authors.forename: Katja
authors.initials: K
authors.lastname: Polman
mesh_terms: D000293:Adolescent; D017195:Adolescent Nutritional Physiological Phenomena; D002648:Child; D002664:Child Nutritional Physiological Phenomena; D002675:Child, Preschool; D005260:Female; D006373:Helminthiasis / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control; D006801:Humans; D008297:Male; D018977:Micronutrients / Q000008:administration & dosage / Q000172:deficiency* / Q000627:therapeutic use; D009752:Nutritional Status; D064887:Observational Studies as Topic; D015995:Prevalence; D016032:Randomized Controlled Trials as Topic; D012008:Recurrence; D012307:Risk Factors
chemical_list: D018977:Micronutrients