Healthy Donor Effect
To examine any potential association between whole blood donation and its health impact on blood donors, it becomes imperative to adjust for the Healthy Donor Effect (HDE). The HDE is the self-selection of a healthier subset of the general (and donor) population. The HDE may occur at the initial recruitment of the donor population, but also when donors who do not meet the eligibility criteria for donation do not return to the blood bank. It is important to note that due to a lack of and possibly improper adjustment for the HDE and other unmeasured confounding, previous studies have been inconclusive regarding the causal effect of blood donation on health outcomes such as cancer and cardiovascular pathology.