The Effect of Repeated Blood Donations on the Iron Status of Iranian Blood Donors Attending the Iranian Blood Transfusion Organization

Abstract

Objective: Blood donation leads to substantial iron loss, as about 0.5 mg iron is lost per each milliliter of blood donated. If not compensated for efficiently, the iron loss may eventually lead to anemia, though non-anemic iron deficiency per se may be problematic. The aim of this study was to evaluate the effects of blood donation, and its frequency over a year’s time, on iron status of Iranian male blood donors attended blood transfusion stations of the Iranian Blood Transfusion Organization (IBTO). Design and setting: A cross-sectional, descriptive, and analytic study was conducted. 91 male volunteer blood donors aged from 20 to 50 years attending three IBTO stations located in central areas of Tehran, and 63 apparently healthy controls that were matched for age, gender, monthly income, height, and weight, were included in the study. Blood donors were divided into 4 groups according to the frequency of blood donation per year; i.e. 1, 2, 3, and 4 with 20, 30, 26, and 15 persons in each group, respectively. Just before blood donation, 10 mL venous blood sample was taken and divided into heparinized and non-heparinized tubes for determination of hemoglobin (Hb), hematocrit (Hct), serum iron (SI), total iron binding capacity (TIBC), ferritin, transferrin saturation (TS), and mean corpuscular hemoglobin concentration (MCHC). Dietary assessment was also done using 3 different questionnaires; i.e. general health, food frequency, and 24hr recall. Results: The levels of Hb, Hct, and iron status indices were all significantly lower in the subjects than in controls and a gradual but significant decrease in iron status indices in each time of blood donation was found. Serum ferritin showed significant correlations with age (r = 0.33, p < 0.001) and body-mass index (BMI) (r = 0.26, p = 0.03) only in the control group. Frequency of blood donation per year was also inversely correlated with Hb (r = -0.67, p < 0.001), Hct (r = -0.65, p < 0.001), MCHC (r = -0.56, p < 0.001), serum ferritin (r = -0.38, p < 0.001), SI (r = -0.62, p < 0.001), and TS (r = -0.61, p < 0.001), but was directly correlated with TIBC (r = 0.56, p < 0.001). Interestingly in blood donors, but not in healthy controls, serum ferritin levels showed weak but statistically significant correlations with daily intake of iron (r = 0.17, p < 0.05) and energy (r = 0.20, p = 0.03). Conclusion: Though repeated blood donations might diminish iron status, it could be safe to donate 2–3 U/year without an appreciable incidence of iron deficiency, provided that the pre-donation Hb and ferritin values are ≥ 14.7 g/dL and 58.9 μg/L, respectively. The male volunteers with Hb ≥ 14.2 g/dL and serum ferritin ≥ 57.2 μg/L could donate 1–2 U/year and those with Hb ≥ 13.1 g/dL and serum ferritin ≥ 35.3 μg/L could donate just once a year. Volunteers who undergo (repeated) blood donation should receive special nutritional care, especially in terms of iron and energy.