Daily calcium supplementation had no effect on the least-squares mean concentrations of iron-status markers adjusted for their baseline values ( hemoglobin : 136 and 134 g/L , P = 0.31 ; ferritin : 25.4 and 26.1 microg/L , P = 0.73 ; TfR : 4.1 and 4.4 mg/L , P = 0.12 ; and the ratio of TfR to ferritin : 160 and 161 in the calcium and placebo groups , respectively ; P = 0.97 ) .
