Prospective Study of Plasma Carotenoids and Tocopherols in Relation to Risk of Ischemic Stroke

Abstract

Background and Purpose - Intake of fruits and vegetables has been related to lower risk of ischemic stroke, but nutrients responsible for this apparent benefit remain ill-defined. Tocopherols ( vitamin E) have also been proposed to be protective.Methods - We conducted a prospective, nested case-control analysis among male physicians without diagnosed cardiovascular disease followed-up for up to 13 years in the Physicians' Health Study. Samples from 297 physicians with ischemic stroke were analyzed with paired controls, matched for age and smoking, for 5 major carotenoids (alpha- and beta-carotene, beta-cryptoxanthin, lutein, and lycopene), retinol, and alpha- and gamma-tocopherol.Results - Baseline plasma levels of alpha- carotene and beta-carotene and lycopene tended to be inversely related to risk of ischemic stroke with an apparent threshold effect. As compared with men whose plasma levels were in the lowest quintile, the multivariate adjusted odds ratios (ORs) of ischemic stroke among men with levels in the second through fifth quintiles were 0.59 (95% CI, 0.36 to 0.98) for alpha-carotene, 0.62 ( 95% CI, 0.38 to 1.01) for beta-carotene, and 0.61 ( 95% CI, 0.37 to 1.00) for lycopene. A tendency toward an inverse association was found for beta-cryptoxanthin, but the result was not statistically significant. No association was found for lutein, retinol, and tocopherols.Conclusion - Our data suggest that higher plasma levels of carotenoids, as markers of fruit and vegetable intake, are inversely related to risk of ischemic stroke and provide support for recommendations to consume fruits and vegetables regularly.