Dietary antioxidant capacity and risk for stroke in a prospective cohort study of Swedish men and women

Abstract

Objective: Both observational studies and randomized trials have shown that a diet rich in antioxidants can reduce systemic inflammation and oxidative stress, two conditions that, together with obesity and smoking, are established risk factors for stroke. However, the association between antioxidant intake and risk for stroke is poorly understood, particularly when studying possible interaction with sex. We investigated the relationship of nonenzymatic antioxidant capacity (NEAC) on risk for stroke in a large Swedish prospective cohort.

Methods: The cohort study included 34 555 men and women from the Swedish National March Cohort. NEAC was assessed using a detailed food frequency questionnaire, collected at baseline. We achieved complete follow-up from enrollment in 1997 through 2010 by record linkage to nationwide registers. We identified 1186 incident cases of a first stroke, of which 860 were ischemic, 201 hemorrhagic, and 125 unspecified. We used multivariable Cox proportional hazards models to estimate adjusted hazard ratios (HR) with 95% confidence intervals (CIs).

Results: Compared with women in the lowest quartile of NEAC, women in the highest quartile had a 27% lower incidence of total stroke (HR, 0.73; 95% CI, 0.53-0.99; P_trend = 0.03) and 35% lower incidence of ischemic stroke (HR, 0.65; 95% CI, 0.43-0.99; P_trend = 0.01). Among men, the relationship between NEAC and risk for stroke was not statistically significant and all HRs were close to unity.

Conclusion: Findings from the present study suggest that dietary antioxidant capacity from different foods and beverages is inversely associated with risk for stroke, more specifically ischemic stroke, in women.

Keywords: Antioxidant effects; Atherosclerosis; Cohort studies; Dietary habits; Epidemiology; Risk factors; Stroke.