Migraine and subsequent risk of stroke in the Physicians' Health Study.

Objective: To evaluate, in a prospective design, whether migraine is an independent risk factor for subsequent stroke.

Design: Evaluated as part of the Physicians' Health Study, a randomized, double-blind, placebo-controlled trial of aspirin and beta-carotene in the primary prevention of cardiovascular disease and cancer begun in 1982. The aspirin component of the study was terminated in 1988, with average follow-up of 60.