HAMP and thalassemia: We found no significant association between geometric mean hepcidin concentrations and either sickle cell trait (for HbAA 2·48 ng/ml; 95% CI 2·08, 2·97; and for HbAS 2·15 ng/ml; 1·32, 3·50; p = 0·63) or α-thalassaemia (for αα/αα 2·64 ng/ml; 95% CI 1·96, 3·56; for − α/αα 2·31 ng/ml; 1·82, 2·93; p = 0·56 and for − α/− α 2·27 ng/ml; 1·48, 3·50; p = 0·61).