Von Willebrand factor and risk of ischemic stroke.

We carried out a case-control study to determine whether von Willebrand factor (vWF) antigen (and factor VII and tissue plasminogen activator [tPA] antigens) are associated with ischemic stroke. Ninety-five patients with transient ischemic attack or minor ischemic stroke recruited from the Oxfordshire Community Stroke Project and one neurology clinic were compared with 236 controls, group-matched for age and sex, from the same general practitioners as the incident cases. In crude analyses, concentrations of vWF antigen were significantly higher in cases than in controls (p = 0.004). The age- and sex-adjusted odds ratios from lowest (referent) to highest quartile of vWF antigen were 1.00, 1.15, 2.34, and 2.36 (trend test, p = 0.006). Factor VII antigen and tPA antigen were not significantly different between cases and controls. Although adjustment for other potential risk factors abolished the statistical significance of the association between vWF and disease, this was largely due to the influence of history of ischemic heart disease. We conclude that vWF is a potent and independent risk factor for transient ischemic attack, minor ischemic stroke, and, by extrapolation, ischemic stroke in general. The data also suggest that vWF may be a risk factor for both ischemic stroke and ischemic heart disease. We found no evidence to implicate factor VII and tPA as risk factors for ischemic stroke.