Deworming drugs for treating soil-transmitted intestinal worms in children: effects on growth and school performance.
BACKGROUND
In areas where intestinal worm infections occur, the World Health Organization recommends treating all school children at regular intervals with deworming drugs to improve growth and school performance. The evidence base for this policy needs to be established for countries to commit resources to implement these programmes.


OBJECTIVE
To summarize the effects of deworming drugs used to treat soil-transmitted intestinal worms (nematode geohelminths) on growth and school performance in children.


METHODS
In May 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2007, Issue 2), MEDLINE, EMBASE, LILACS, mRCT, and reference lists.


METHODS
Randomized and quasi-randomized controlled trials (RCTs) comparing deworming drugs for geohelminth worms with placebo or no treatment in children aged 16 years or less, reporting on growth, nutritional status, school performance, or cognition tests.


METHODS
Two authors independently assessed the trials and evaluated methodological quality; one author extracted data, and another checked a sample. Continuous data were analysed using the weighted mean difference (WMD) with 95% confidence intervals (CI). The random-effects model (RE model) was used in the presence of statistically significant heterogeneity.


RESULTS
Thirty-four RCTs, including six cluster-RCTs, met the inclusion criteria. Four trials had adequate allocation concealment, and three cluster-RCTs failed to take design effects into account in their analysis. Weight increased after one dose of a deworming drug (WMD 0.34 kg, 95% CI 0.05 to 0.64, RE model; 2448 children, 9 trials); however, there was considerable heterogeneity between trials that was not explained by background intestinal worm infection or intensity. A meta-analysis of multiple dose trials reporting on outcomes within a year of starting treatment showed no significant difference in weight gain (1714 children, 6 trials); however, one cluster-RCT did show effects on weight at one year in a subgroup analysis. In the seven multiple dose trials with follow up beyond 12 months, only one showed a significant increase in weight. Six of seven trials reported clear data on cognitive tests and school performance: five reported no significant effects, and one showed some improvements in three out of 10 cognitive tests.


CONCLUSIONS
Deworming drugs used in targeted community programmes may be effective in relation to weight gain in some circumstances but not in others. No effect on cognition or school performance has been demonstrated.
Taylor-Robinson
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DC
Liverpool School of Tropical Medicine, International Health Group, Pembroke Place, Liverpool, Merseyside, UK, L3 5QA. David.Taylor-Robinson@liverpool.ac.uk
Jones
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AP
Garner
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D000293:Adolescent; D000871:Anthelmintics / Q000494:pharmacology / Q000627:therapeutic use*; D002648:Child; D002657:Child Development / Q000187:drug effects*; D002675:Child, Preschool; D003071:Cognition / Q000187:drug effects*; D006128:Growth / Q000187:drug effects*; D006373:Helminthiasis / Q000150:complications / Q000188:drug therapy*; D006801:Humans; D007411:Intestinal Diseases, Parasitic / Q000150:complications / Q000188:drug therapy*; D009752:Nutritional Status / Q000187:drug effects; D016032:Randomized Controlled Trials as Topic; D015430:Weight Gain / Q000187:drug effects
D000871:Anthelmintics