Roschnik 2003 (C).

Study characteristics
Methods	Design: 2‐arm, cluster‐randomised trial Unit of randomisation: school level (40 schools) and stratified by sponsorship status
Participants	Setting/location: 40 primary schools in the Mangochi District, Malawi Sample size: 752 boys and girls (from 1160 randomised) Age range: for 371 girls; ~ 7–8 years (standard 2 grade) and ~ 12‐15 years (standard 6 grade) Baseline prevalence of anaemia: around 54% Inclusion criteria: registered children Exclusion criteria: not available
Interventions	371 girls were randomly allocated to 1 of 2 groups. Group 1 (n = 184 at follow‐up): participants received 65 mg of elemental iron (as 200 mg of ferrous sulphate) and 250 μg (0.25 mg) of folic acid once a week. Group 2 (n = 187 at follow‐up): participants received no intervention. Length of the intervention: 15 weeks
Outcomes	Haemoglobin concentration Bilharzia infection School attendance Test scores Dropout rate* Repetition rate* *(at school level)
Notes	Comments: A famine occurred in the region at the time of the study. Each study group included 10 sponsorship schools and 10 non‐sponsorship schools, 10 coastal, and 10 upland schools. All children in coastal intervention and comparison schools, where the prevalence of bilharzia was over 50%, were dewormed with praziquantel (600 mg) just after the baseline survey. A vitamin A capsule (200,000 IU) was given to all children in standard 2 and below. 63% of children took 10 iron tablets or more. Malaria endemicity was not reported. We adjusted the results of this study to account for the effect of clustering in the data; we used the estimated effective sample size in the analyses.  Study start date: July 2001 Study end date: not available Funding source: not available Conflicts of interest: not available
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: 40 primary schools in the Mangochi District were randomly divided into the intervention (1st iron group) and comparison group (2nd iron group). Each group included 10 sponsorship schools and 10 non‐sponsorship schools. Method of sequence generation not specified
Allocation concealment (selection bias)	Low risk	Comment: not reported; however, since the intervention was allocated at school level, selection bias at individual level is unlikely
Blinding (performance bias and detection bias) All outcomes	Low risk	Comment: not mentioned; however, as randomisation was at class level, it is unlikely that participants were blinded. Not reported for personnel or outcome assessors
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: 1280 were randomised, 1160 had haemoglobin levels at baseline and 752 were followed up. 41.2% children lost to follow‐up
Selective reporting (reporting bias)	Unclear risk	Comment: insufficient information to permit judgement
Other bias	Unclear risk	Comment: children attending sponsored schools responded better to the treatment