摘要：Context: Basic research provides plausible m.chanism. and observational studies suggest that apparently healthy persons, who self-select for high intakes of vitam.n E through diet or supplem.nts, have decreased risks of cardiovascular disease and cancer. Random.zed trials do not generally support benefits of vitam.n E, but there are few trials of long duration am.ng initially healthy persons. Obj.ctive: To test whether vitam.n E supplem.ntation decreases risks of cardiovascular disease and cancer am.ng healthy wom.n. Design, Setting, and Participants: In the Wom.n’s Health Study conducted between 1992 and 2004, 39 876 apparently healthy US wom.n aged at least 45 years were random.y assigned to receive vitam.n E or placebo and aspirin or placebo, using a 2×2 factorial design, and were followed up for an average of 10.1 years. Intervention: Adm.nistration of 600 IU of natural-source vitam.n E on alternate days. m.in Outcom. m.asures: Prim.ry outcom.s were a com.osite end point of first m.j.r cardiovascular event(nonfatal m.ocardial infarction, nonfatal stroke, or cardiovascular death) and total invasive cancer. Results: During follow-up, there were 482 m.j.r cardiovascular events in the vitam.n E group and 517 in the placebo group, a nonsignificant 7%risk reduction(relative risk[RR], 0.93; 95%confidence interval[CI], 0.82-1.05; P=.26). There were no significant effects on the incidences of m.ocardial infarction(RR, 1.01; 95%CI, 0.82-1.23; P=.96) or stroke(RR, 0.98; 95%CI, 0.82-1.17; P=.82), as well as ischem.c or hem.rrhagic stroke. For cardiovascular death, there was a significant 24%reduction(RR, 0.76; 95%CI, 0.59-0.98; P=.03). There was no significant effect on the incidences of total cancer(1437 cases in the vitam.n E group and 1428 in the placebo group; RR, 1.01; 95%CI, 0.94-1.08; P=.87) or breast(RR, 1.00; 95%CI, 0.90-1.12; P=.95), lung(RR, 1.09; 95%CI, 0.83-1.44; P=.52), or colon cancers(RR, 1.00; 95%CI, 0.77-1.31; P=.99). Cancer deaths also did not differ sign