Dietary fiber intake and stroke risk: a meta-analysis of prospective cohort studies

BACKGROUND/OBJECTIVES: Epidemiological studies have suggested that dietary fiber intake may be associated with a decreased risk of stroke, but the findings have been inconsistent. We aimed to assess this association by conducting a meta-analysis of prospective cohort studies. SUBJECTS/METHODS: We performed a literature search on PubMed database through July 2012 to indentify prospective studies of dietary fiber intake in relation to risk of stroke. We also comprehensively reviewed the reference lists of the retrieved articles to identify additional studies. We used a random-effects model to compute the summary risk estimates. RESULTS: Six prospective cohort studies containing a total of 314 864 subjects and 8920 stroke cases were included. The summary relative risk (RR) of stroke for the highest vs lowest category of dietary fiber intake was 0.87 (95% confidence interval (Cl), 0.77-0.99). The corresponding RR in the subgroup analyses for men and women was 0.95 (95% CI, 0.83-1.08) and 0.80 (95% CI, 0.66-0.96), respectively; and for ischemic stroke and hemorrhagic stroke was 0.83(95% CI, 0.72-0.96) and 0.86 (95% CI, 0.70-1.06), respectively. Meta-regression indicated no significant difference between gender (P-interaction = 0.18), or stroke subtypes (P-interaction = 0.85). The dose-response analysis suggested a 12% (RR=0.88; 95% CI, 0.79-0.97) reduction in risk of stroke for each 10 g per day increment in dietary fiber intake. Moderate heterogeneity emerged in some of analyses, but disappeared after removing one study substantially contributing to the heterogeneity. Little evidence of publication bias was detected. CONCLUSION: Findings of this meta-analysis indicate a significant inverse dose-response relationship between dietary fiber intake and risk of stroke. European Journal of Clinical Nutrition (2013) 67, 96-100; doi:10.1038/ejcn.2012.158; published online 17 October 2012