Charoenlarp 1988.

Methods	Design: two randomised controlled trials Randomisation: individual Trial: Trial 1: daily iron at 2 different doses with and without supervision versus placebo. Trial 2: daily iron at two different doses with and without folic acid versus placebo Date of study: Trial 1: 1977 to 1979, Trial 2: 1978 to 1980 TWO STUDIES: Study A: Non‐pregnant women and men; data for women presented separately. Participants with haemoglobin E or B thalassaemia trait were excluded. Study performed between March 1977 and March 1979 Study C: Study performed between September 1978 and August 1980
Participants	Setting: Trial 1: Rural area of Central Thailand 80 km north of Bangkok near Ayudhya. Trial 2: Northern Thailand; two villages 50 km south and 100 km south west of Chiang Mai Malaria endemicity: malaria is endemic to both trials Included: women of fertile age Trial 1: age range 15 years to 45 years (mean age not stated) Trial 2: age range 16 years to 45 years (mean age not stated) Excluded: Haemoglobin < 80, thalassaemia trait or disease, uncooperative Dropouts: Trial 1: 16% across all groups (reported as similar), Trial 2: reported at 36%, group status unclear Sample size: total: 863; intervention: 690, control: 173
Interventions	Intervention: Trial 1: 5 groups: placebo, daily iron 120 mg supervised, daily iron 240 mg supervised, daily iron 240 mg + 5 mg folic acid supervised, daily iron 120 mg unsupervised Trial 2: 4 groups: placebo, daily iron 120 mg, daily iron 240 mg, daily iron 240 mg plus 5 mg of folic acid Control: placebo Duration: 3 months
Outcomes	Anaemia, haemoglobin, iron status
Notes	Compliance: not stated Conflicts of interest: not stated. Funded by: World Health Organization (WHO), Belgian administration of co‐operation to development, Danish International Development Authority, and Swedish International Development Authority
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Placebo used
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Placebo used
Incomplete outcome data (attrition bias) All outcomes	High risk	Loss to follow‐up: 16% in trial 1 and 36.6% in trial 2
Selective reporting (reporting bias)	Low risk	Not evident
Other bias	Low risk	Not evident