Homeostatic Model Assessment of Insulin Activity and Iron Profile among Regular Blood Donors at a Tertiary Health Centre, South-West Nigeria

Context: Iron overload has been established to play a role in the etiopathogenesis of Type 2 diabetes mellitus (DM) as evidenced by its high prevalence among patients with hemochromatosis and transfusion-dependent diseases. This is as a result of iron redox reaction which generates free radicals that cause peroxidation of lipid-rich pancreas, leading to reduced insulin sensitivity. Aims: This study therefore evaluated the impact of regular blood donation, an effective method of reducing iron load, on beta -islet cell functions and level of glycemic control among regular whole blood donors. Settings and Design: This is a cross-sectional, analytical study. Subjects and Methods: Forty-two consenting regular blood donors who had donated whole blood at least twice and not more than thrice in the last 1 year were selected as cases, while 42 age-matched individuals who have never donated blood previously were selected as controls. Samples were obtained and analyzed for fasting plasma glucose, fasting plasma insulin, serum ferritin, transferrin receptor, total iron-binding capacity (TIBC), and serum iron, while Homeostatic Model Assessment (HOMA) of insulin resistance (IR) and beta sensitivity, HOMA-IR, and HOMA-beta -cell function (HOMA-beta%) were calculated for both groups. Statistical Analysis Used: Statistical analysis was done using Microsoft Excel package and the Statistical Package for the Social Sciences (SPSS) version 20.0 (SPSS Inc., Chicago, IL, USA). Results: Iron studies among regular blood donors and nondonors revealed lower serum iron (37.2 +/- 7.3 vs. 41.1 +/- 7.9 mu mol/L, P = 0.180) and lower serum ferritin levels (30.2 +/- 26.1 vs. 42.9 +/- 38.5 ng/mL, P = 0.117), which were not statistically significant, while there were higher serum transferrin receptor (155.5 +/- 22.6 vs. 112.8 +/- 43.4 ng/mL, P < 0.001) and higher serum TIBC (42.3 <plus/minus> 6.4 vs. 37.8 +/- 7.4 mu mol/L, P < 0.05), among cases than controls. The mean HOMA-IR and HOMA-% were also significantly better among donors than nondonors. Conclusions: Regular blood donation may protect the body from the toxic effects of excessive iron store, which includes improved insulin sensitivity and glycemic control.