The prevalence of iron-deficiency anemia (IDA) in young children at the time of stroke and in age-matched healthy controls was compared in a case-control study conducted at the Hospital for Sick Children, Toronto, Canada. IDA was significantly more common among case patients (8 (53%) of 15) than control subjects (13 (9%) of 143). Patients and controls were aged 12 to 38 months; median ages of 24 vs 21 months were not significantly different. Case patients had a lower median hemoglobin level and mean corpuscular volume and a higher median platelet count than controls. Patients with IDA had serum ferritin levels below 12 mcg/L. Three stroke cases without IDA had varicella infection and prior prothrombotic risk factors. Six stroke cases (4 with IDA) had acute otitis media, pneumonia, or acute gastroenteritis infections. Stroke patients were 10 times more likely to have IDA than healthy children without stroke. More than half of all stroke cases in otherwise healthy children had IDA as a risk factor. Stroke due to sinovenous thrombosis was more closely associated with IDA than arterial ischemic stroke. 
COMMENT. IDA is a significant risk factor for vasoocclusive stroke in otherwise healthy children. In a series of 212 children with a first ischemic stroke, reported from Great Ormond Street Hospital, London, a previous medical diagnosis was identified in approximately one half, including anemia in 40%. [2, 3] Other risk factors include activated protein C resistance, elevated lipoprotein(a), antiphospholipid antibodies, prothrombin gene variant, factor V Leiden mutation, subacute varicella infection, and methylenetetrahydrofolate reductase (MTHFR) mutation. IDA is a greater risk factor for sinovenous thrombosis than for arterial ischemic stroke.