Changes in metabolic indices in response to whole blood donation in male subjects with normal glucose tolerance

OBJECTIVES: Previous studies have investigated the impact of venesection upon different metabolic indices in patients with various conditions (e.g., type 2 diabetes and iron overload). We aimed to investigate the changes on different metabolic indices including glycemic, iron, lipids and inflammatory markers at different time points after blood donation in male subjects with normal glucose tolerance. DESIGN AND METHODS: 42 male subjects were recruited to the study. Glucose tolerance was assessed by oral glucose tolerance test before (visit A) and after the blood donation (1day, visit B; 1week, visit C; 3weeks, visit D; and 3months, visit E). Fasting glucose, HbA1c, insulin, lipids, uric acid, C-reactive protein, iron stores and insulin resistance (HOMA-IR, ISI-gly) indices were measured. A repeated measures ANOVA was used for comparisons of quantitative variables between different visits. RESULTS: All subjects had normal glucose tolerance according to WHO criteria. Fasting glucose, insulin and HOMA-IR were significantly higher (~2%, p<0.05; ~21%, p<0.01; and ~11%, p<0.05 respectively) at visit B following donation. At visit D, the mean±SE for HbA1c (5.28±0.06%) was significantly lower with a difference in percentage of ~-3% and p<0.05 compared to visit A (5.44±0.06%). Ferritin decreased significantly at visits B, C, D and E (~-8%, p<0.01, ~-24%, p<0.001, ~-39%, p<0.001 and ~-29%, p<0.01 respectively), when compared to visit A. CONCLUSIONS: At different time points after blood donation, glycemic status and iron stores are affected significantly in male blood donors with normal glucose tolerance. The changes were particularly evident three weeks after donation. Hence, the interpretation of these parameters in male blood donors needs to take this into account, and the mechanisms resulting in these effects need to be clarified