Fogelholm 1992.

Methods	Design: randomised controlled trial Randomisation: individual. Randomisation stratified by menstrual status (regular/irregular) Trial: daily oral iron versus placebo Date of study: not stated
Participants	Setting: sports teams in Finland (athletics, basketball, handball) Malaria endemicity: not stated Included: women from sport teams aged 17 years to 31 years (mean age not reported, median age 24 years), with subclinical iron depletion (ferritin < 25 mg/mL, haemoglobin > 120 g/L) Excluded: not stated Dropouts: 2 from intervention group, none from control group Sample size: total: 31; intervention: 14, control: 17
Interventions	Intervention: 100 mg elemental iron as ferrous sulphate Control: placebo Duration: 8 weeks
Outcomes	Haemoglobin, iron status, VO2 max
Notes	Compliance: not stated Conflicts of interest: not stated Funded by: grant from the Ministry of Education (presumed of Finland)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random permutated blocks
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Placebo administered
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported. Exercise outcomes could be influenced by knowledge of allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	No attrition
Selective reporting (reporting bias)	Unclear risk	HR and oxygen consumption data stated to be non significantly different between arms but data not shown. Lactate only shown in a figure
Other bias	Low risk	Not evident