No Evidence of Increased Risk of Stroke with Consumption of Refined Grains: A Meta-analysis of Prospective Cohort Studies

Objectives: Results of the relationships between dietary consumption of refined grains and the risk of stroke are mixed. This study was based on a meta-analysis of prospective cohort studies. Methods: We systematically searched the MEDLINE (from January 1, 1966) and EMBASE (from January 1, 1974) databases up to November 30, 2014. Random-effects models were used to calculate summary relative risks (SRRs) and 95% confidence intervals (CIs). Between-study heterogeneity was assessed using Cochran's Q and I-2 statistics. Results: Eight prospective studies (7 publications) with a total of 410,821 subjects and 8284 stroke events were included in the meta-analysis. Overall, a diet containing greater amounts of refined grains was not associated with risk of stroke, with no evidence of heterogeneity among studies (SRR = 1.02; 95% CI, .93-1.10; P-heterogeneity = .970; I-2 = 0). In addition, no significant associations between consumption of refined grains and risk of stroke were found for both women and men, for both hemorrhagic and ischemic strokes, and for both incident and fatal strokes. These null results are consistent with those of linear dose-response meta-analyses (SRR = .98; 95% CI, .73-1.03 for per 3 servings/day). Consumption of white rice was not associated with risk of stroke (SRR = 1.01; 95% CI, .93-1.11; P-heterogeneity = .966; I-2 = 0). Conclusions: The current meta-analysis provides some evidence for the hypothesis that consumption of refined grains was not associated with risk of stroke and its subtypes.