A positive relation between high hemoglobin values and the risk of ischemic stroke

We examined the relationship between the hemoglobin concentration and the risk of ischemic stroke using data from a hospital-based case-control study. A total of 143 patients (age 30-69 years) with a diagnosis of cerebral infarction confirmed by computerized tomography scan and 143 age- and sex-matched controls entered the study. Hemoglobin was higher in the patients with stroke (14.2 +/- 1.6 g/l, mean +/- SD) than in controls(l3.7 +/- 1.6 gn; p < 0.05). Compared with subjects with hemoglobin levels of less than 13 g/l (reference category), the relative risk of ischemic stroke, after allowance for potential risk factors, was 2.0 (95% CI 0.8-4.9) for the 13-13.9 g/l quartile, 2.8 (95% CI 1.2-6.5) for the 14-14.9 gn quartile, and 3.2 (95% CI 1.4-7.4) for the 14+ g/l quartile (chi(2) for linear trend 7.27, p < 0.01). We conclude that the hemoglobin concentration may be an indicator of risk for ischemic stroke.