Iron status and haematological changes in adolescent female inpatients with anorexia nervosa

Objective: (i) To investigate the incidence of iron deficiency (both latent iron deficiency and iron deficiency anaemia) in post menarchal female adolescent patients hospitalized with anorexia nervosa. (ii) To observe changes in iron status during refeeding. Methods: During the study period all post menarchal female patients admitted to the adolescent unit with anorexia nervosa were invited to participate. Ferritin, serum iron, transferrin and transferrin saturation were measured on admission and discharge. Haemoglobin, haematocrit, weight, and body mass index were monitored weekly. Results: All 12 eligible patients participated in the study. Four patients had elevated ferritin levels on admission. Ten of the 12 showed a statistically significant fall in serum ferritin at time of discharge compared with admission (P = 0.004). One of 12 patients had a low serum iron at presentation. All 12 had normal serum iron levels at discharge. Nine of the 12 subjects had a higher serum iron at discharge which was statistically significant (P = 0.046). There was no significant change in haemoglobin levels when comparing admission and discharge levels. Nine of the 12 patients however, transiently developed anaemia, at some stage during treatment. Conclusions: Iron deficiency is uncommon at both presentation and after nutritional rehabilitation in post menarchal adolescent females with anorexia nervosa. This is most likely due to increased iron storage secondary to the contraction of the circulating blood volume and reduced iron losses from (secondary) amenorrhoea. The fall in ferritin observed during treatment is due to haemopoiesis necessary to fill the increased blood volume associated with weight gain. This also results in normalization of the haemoglobin and haematocrit.