Observational data suggest that diets rich in fruits and vegetables and with high serum levels of
antioxidants are associated with decreased incidence and mortality of
stroke. We studied the effects of
alpha-tocopherol and
beta-carotene supplementation. The incidence and mortality of
stroke were examined in 28 519 male cigarette smokers aged 50 to 69 years without history of
stroke who participated in the
Alpha-Tocopherol,
Beta-Carotene Cancer Prevention Study (ATBC Study). The daily supplementation was 50 mg
alpha-tocopherol, 20 mg
beta-carotene, both, or placebo. The median follow-up was 6.0 years. A total of 1057 men suffered from incident
stroke: 85 men had
subarachnoid hemorrhage; 112,
intracerebral hemorrhage; 807,
cerebral infarction; and 53, unspecified
stroke. Deaths due to
stroke within 3 months numbered 38, 50, 65, and 7, respectively (total 160).
alpha-Tocopherol supplementation increased the risk of
subarachnoid hemorrhage 50% (95% CI -3% to 132%, P=0.07) but decreased that of
cerebral infarction 14% (95% CI -25% to -1%, P=0.03), whereas
beta-carotene supplementation increased the risk of
intracerebral hemorrhage 62% (95% CI 10% to 136%, P=0.01).
alpha-Tocopherol supplementation also increased the risk of fatal
subarachnoid hemorrhage 181% (95% CI 37% to 479%, P=0.01). The overall net effects of either supplementation on the incidence and mortality from total
stroke were nonsignificant.
alpha-Tocopherol supplementation increases the risk of fatal
hemorrhagic strokes but prevents
cerebral infarction. The effects may be due to the antiplatelet actions of
alpha-tocopherol.
beta-Carotene supplementation increases the risk of
intracerebral hemorrhage, but no obvious mechanism is available.