Cluster randomized trial of the impact of school based deworming and weekly iron supplementation on haemoglobin level of plantation primary school children

Abstract

BACKGROUND: School-based deworming and iron supplementation are being promoted as effective interventions to deal with the high prevalence of anaemia among school children. OBJECTIVE: The objective of this study was to determine the effectiveness of school based deworming and weekly iron supplementation on increasing the haemoglobin level of primary school children in the plantation sector in Sri Lanka. METHODS: A placebo-controlled cluster randomized trial was conducted in which the treatment group received a single dose of 500 mg mebendazole and 6-months of weekly iron supplementation (200 mg ferrous sulphate) while the control group received placebo for both anthelmintic and iron. The tablets were administered by the class teacher. Children attending grade 4 in schools in the plantation sector were recruited. The treatment arm was allocated with 813 children attending 49 schools and the placebo arm with 808 children attending 49 schools. Height, weight and haemoglobin were measured at baseline and after 6-months. A regression model adjusting for the cluster design was used to assess the effectiveness of the intervention on the haemoglobin level. In order to increase the precision of the estimates, various background variables were controlled for in regression models. RESULTS: Complete data were available for 633 children in the treatment group and 613 children in the control group. The mean age was 9 years and 6 months and 52% of them were males. In the treatment arm 98% had received mebendazole and over 80% had received 16 doses of iron. A reduction in the prevalence of soil-transmitted helminth (STH) infection (from 25.1% to 16.4%) was found in the treatment group, with significant differences between treatment and control groups in the levels of Ascaris and Trichuris. There was a small non-significant reduction in the mean haemoglobin level (at baseline 12.6g/dl, sd - 1.2) of both groups. No impact of treatment was found on haemoglobin levels. CONCLUSIONS: Though the intervention was effective in reducing the prevalence of STH infection there was no evidence of effectiveness in increasing haemoglobin levels.