Schultink 1995.

Methods	Randomised clinical trial. 2‐arm design with individual randomisation.
Participants	87 children, both sexes, aged 2‐5 years, from Subdistrict Kelurahan Tenga of East Jakarta, Indonesia. The initial selection criterion was a haemoglobin concentration < 110 g/L. 96 children were invited to receive anthelmintic treatment before starting iron supplementation; only 87 accepted and were randomised.
Interventions	Participants were allocated to one of the following groups: Group 1 (n = 44): children were supplemented daily with 30 mg elemental iron (as ferrous sulphate dissolved in 5 mL syrup); Group 2 (n = 43): children were supplemented twice a week with 30 mg elemental iron (as ferrous sulphate dissolved in 5 mL syrup) (total 60 mg of iron per week). Length of the intervention: 8 weeks.
Outcomes	Haemoglobin, ferritin, zinc protoporphyrin, mean changes of haematological variables (anaemia prevalence taken from Beaton 1999).
Notes	Parents and supervising health staff were instructed that each child should take 5 mL from the small bottle on Mondays and Fridays and 5 mL from the large bottle on the remaining days of the week using a standardized spoon for 8 wk. Bottles had similar appearance Malaria endemicity not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Subjects were assigned at random to two groups. Method of sequence generation not described.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Blinding (performance bias and detection bias) All outcomes	Low risk	Participants: were not aware of the treatment Personnel: all mothers received two small bottles (each 80 mL) and two large bottles (each 170 mL), each containing a syrup of similar appearance Outcome assessors: supervising staff were not aware of the bottle content.
Incomplete outcome data (attrition bias) All outcomes	High risk	A complete set of data was obtained for 33 subjects in the group supplemented twice weekly (group 1) (75%) and for 32 subjects in the group supplemented daily (group 2) (74.4%).
Selective reporting (reporting bias)	Unclear risk	There is insufficient information to permit judgement.
Other bias	High risk	Baseline haemoglobin concentrations were different between groups. The results include 25 children with Hb> 110 g/L and the initial description only mentions 16