The incidence of cardiovascular disease increases progressively with age in men and is more common in younger men than in women of similar age. The difference in incidence of cardiovascular disease between the sexes diminishes in the elderly, as the incidence of female cardiovascular disease increases with age in post-menopausal females. This pattern coincides with that of iron stores; in men iron stores increase with age, while menstrual blood loss means that pre-menopausal women have little or no storage of iron with iron only accumulating post-menopause. This link was used by Sullivan¹ to propose that excess iron is important to the pathogenesis of atherosclerosis. Blood donation reduces body iron stores and comparing donors and non-donors provides a way of testing this hypothesis. In two studies the incidence of heart disease was found to be reduced in male blood donors, but no such reduction was found in a later, prospective study of …