GSTM1 and Iron deficiency anemia: The subjects had good iron nutritional statuses (UIBC, SI, sTfR, SF, and Hb) at baseline; none had iron deficiency (SF level < 30 μg/L), early iron deficiency (sTfR >4.4 mg/L) or iron deficiency anemia (SF < 30 μg/L, and Hb < 130 g/L).