Main study parameters/endpoints: The main study endpoint is iron-deficiency anaemia (IDA). IDA will be defined as concurrent anaemia and iron deficiency. Whole blood will be collected for the analysis of Hb, serum ferritin (SF), serum transferring receptor (sTfR) and C-reactive protein (CRP). Anemia will be defined as a hemoglobin concentration <115 g/L, and iron deficiency will be defined as an SF concentration <12 µg/L.