Is blood donation good for the donor?

摘要

Neyers et al in their article "Possible association of a reduction in cardiovascular events with blood donation" invite us to believe that there is a cause and effect relation between blood donation and a reduction in the risk of subsequent vascular events. First of all, their observational study can, at best, provide evidence only of a statistical link between blood donation and a low risk of vascular events. Whether any confirmed association is cause and effect in nature, a reverse association or owing to inade- quate adjustment for unmeasured or unconfirmed con- founders, cannot be addressed adequately by their study.