[Effects of iron supplementation on human serum level of transferrin receptor]

To study trend of dynamic change in level of serum transferrin receptor (sTfR) in the process of iron supplementation to provide evidence for sTfR in evaluating the efficacy of iron supplementation.

Totally, 942 child-bearing-age women aged 18 to 45 years were selected from Longfang City, Hebei Province and Shunyi County, Beijing. Biochemical indicators of iron metabolism were measured for all of them, including serum levels of ferritin (SF) and zinc protoporphyrin (ZPP), and hemoglobin (Hb). According to the current criteria for assessing iron status, women were screened for iron deficiency erythropoiesis (IDE) or iron deficiency anemia (IDA). Seventy-two women agreed to participate in the study, and 59 of them finished whole dynamic observations with signed informed consent. Four capsules of ferrous L-threonate (containing 7 mg of iron element per capsule) were administered for women with IDE every other day and for women with IDA every day, respectively, for 12 weeks. Serum biochemical indicators and level of sTfR were measured in 0 wk, 3 wk, 6 wk, 9 wk and 12 wk, respectively, during the process of iron supplementation, and their dynamic changes were observed.

Level of sTfR in women with IDE and IDA was (26.62 +/- 10.57) nmol/L and (41.25 +/- 21.96) nmol/L, respectively, significantly higher than normal level. During the process of iron supplementation, level of sTfR changed as the following characteristics. In women with IDE, level of sTfR kept stable within the first 3 weeks of iron supplementation, then dropped gradually and progressively, reached to normal, with (17.86 +/- 5.57) nmol/L, in the 12 wk after iron supplementation. In women with IDA, level of sTfR dropped quickly within the first 3 wk of iron supplementation, then dropped slowly until the 9th wk and kept stable, and reached to normal level in the 12 wk, with (19.54 +/- 5.94) nmol/L and a ratio of sTfR/SF of 12.23 +/- 4.34. Ratio of sTfR/SF changed as level of sTfR during the process of iron supplementation. Level of sTfR correlated reversely with levels of Hb and SF and positively with level of ZPP.

Serum level of sTfR in child-bearing age women gradually decreased to normal with the restoration of their normal iron status during the process of iron supplementation and could be used as a specific indicator for assessing efficacy of iron supplementation.