Meta-analysis of the association between whole grain intake and coronary heart disease risk

Epidemiologic studies evaluating the association of whole-grain intake with risk for coronary heart disease (CHD) have produced inconsistent results. The aim of this meta-analysis was to summarize the evidence from observed studies regarding the association between whole-grain intake and risk for CHD. Pertinent studies were identified by searching the Web of Knowledge and PubMed up to July 2014. A random-effects model was used to combine the results. Publication bias was estimated using Begg's funnel plot and Egger's regression asymmetry test. Ultimately, fourteen reports of 18 studies (15 cohort studies and 3 case-control studies) involving 14,427 patients with CHD and 400,492 participants were used in this meta-analysis. Pooled results suggested that highest whole-grain intake amount compared with the lowest amount was significantly associated with reduced risk for CHD (summary relative risk 0.787, 95% confidence interval 0.743 to 0.833), with no between-study heterogeneity observed (I(2) = 0%, p = 0.537). The association was significant in cohort studies but not in case-control studies. Inverse associations were also found in the United States and Europe. No publication bias was found. In conclusion, this meta-analysis indicates that higher whole-grain intake has a protective effect against CHD.