Antioxidant Supplements May Not Reduce Stroke Risk

HELSINKI, Finland--Scientists from the National Public Health Institute in Finland and the U.S. National Cancer Institute in Bethesda, Md. found antioxidant supplements did not reduce the risk of stroke in middle-aged smokers. The Alpha Tocopherol, Beta Carotene Cancer Prevention Study, published in the American Heart Associations August issue of Stroke (35, 8:1908-13, 2004) (www.stroke.ahajournals.org), examined 29,133 male smokers, aged 50 to 69 years. The men were randomized to receive 50 mg of alpha tocopherol, 20 mg of beta carotene, both, or placebo daily for eight years.

The study examined the effects of alpha tocopherol and beta carotene supplementation on stroke and its subtypes during a six-year postintervention. At the beginning of the post-trial follow-up, 24,382 men were still at risk for first-ever stroke. During the post-trial follow-up, 1,327 men experienced a stroke: 1,087 cerebral infarctions, 148 intracerebral hemorrhages, 64 subarachnoid hemorrhages, and 28 unspecified strokes.

Post-trial risk for cerebral infarction was elevated among those who had received alpha tocopherol compared with those who had not (relative risk--RR), (RR 1.13; 1.00 to 1.27), whereas beta carotene had no effect (RR, 0.97; 0.86 to 1.09).

Alpha tocopherol supplementation was associated with a postintervention RR of 1.01 for intracerebral hemorrhage and 1.38 for subarachnoid hemorrhage. The corresponding RRs associated with beta carotene supplementation were 1.38 and 1.09, respectively.

The researchers found alpha tocopherol supplementation decreased the risk of cerebral infarction by 14 percent and beta carotene increased the risk of intracerebral hemorrhage by 62 percent and concluded neither alpha tocopherol nor beta carotene supplementation had any postintervention preventive effects on stroke. The post-trial increase in cerebral infarction risk among recipients of alpha tocopherol may present a rebound of the reduced risk of cerebral infarction during the intervention, the researchers added.