Blood donations, iron stores, and risk of Parkinson's disease.

Iron overload and systemic iron stores may be important in the pathogenesis of Parkinson's disease (PD). We therefore examined the association between blood donations, which reduce body iron stores, and risk of PD in the Health Professionals Follow-Up Study, a large cohort investigation of U.S. men. Our hypothesis was that blood donation reduces the risk of PD by lowering systemic iron stores. Although the number of blood donations was inversely related to the ferritin levels in a subsample of the study population, no association was found between the number of blood donations and risk of PD (P for trend = 0.6). Unexpectedly, the risk of PD was higher among men who reported recent multiple blood donations (P for trend = 0.05). The results of this study do not support the hypothesis that reduced systemic iron stores lower the risk of PD.