Iron deficiency in blood donors: causes, symptoms, and mitigation strategies
Spencer, Bryan Ross
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Transfusion of blood products is a common medical procedure, and maintaining adequate blood supply depends on the unpaid donation of a small share of the general population. The absence of pre-donation testing for iron status allows many donors with iron deficiency to donate blood. This dissertation seeks to enhance our understanding of the causes of iron deficiency among blood donors, the resultant symptoms, and the likely effectiveness of alternate strategies for reducing the risk of iron deficiency. In Study 1, we used data from the REDS-II RISE prospective cohort study, over a 2-year follow-up period, to evaluate whether higher levels of dietary iron protect against incident iron deficiency in blood donors. Responses to a brief checklist of consumption of animal proteins were combined into an Iron Composite Score weighted for iron content and reported frequency. We found that donors reporting the lowest levels of iron consumption were more likely to develop advanced iron depletion during follow-up. In Study 2, we performed an analysis of observational data from the STRIDE study, a randomized trial, to evaluate whether improvements in iron status were associated with improvements in reported fatigue levels. Using linear regression, we found that many donors had sizable changes in both reported levels of fatigue and in measures of iron status, but neither iron status nor changes in iron status was associated with fatigue at the end of 20–24 months follow-up. In Study 3, we conducted a simulation study to evaluate the range of outcomes of different strategies that might be adopted by blood centers to reduce the prevalence of iron depletion in blood donors. Using inputs primarily from the REDS-II program, we simulated approaches that extended the minimum interval between donations, that promoted use of iron supplementation by blood donors, and that performed ferritin testing to determine donor iron stores and extended the donation interval to those with iron depletion. Only extending the current 8-week interval to 26 weeks approached a reduction by half of the proportion of blood donors who were iron deficient, but the estimated impact on blood supply was a 21% drop in blood availability. Those interventions impacting supply less were also less effective in reducing iron depletion.