Nut consumption and the risk of coronary artery disease: a dose-response meta-analysis of 13 prospective studies

Introduction: Epidemiological studies evaluating the association of nut with risk of coronary artery disease (CAD) have produced inconsistent results. We conducted a meta-analysis to summarize the evidence from prospective cohort studies regarding the association between nut consumption and risk of CAD.

Materials and methods: Pertinent studies were identified by searching Web of Knowledge, Pubmed and Wan Fang Med Online up to January 2014. Random-effect model was used to combine the results. Dose-response relationship was assessed by restricted cubic spline. Publication bias was estimated using Begg' funnel plot and Egger's regression asymmetry test.

Results: Nine articles with 13 prospective studies involving 6,127 CAD cases and 347,477 participants were included in this meta-analysis. Pooled results suggested that highest nut consumption amount versus lowest amount was significantly associated with the risk of CAD [summary relative risk (RR)=0.660, 95%CI=0.581-0.748, I(2)=39.6%]. Linear dose-response relationship was found between nut consumption and CAD risk, and the risk of CAD decreased by 5% for every 1 serving/week increase intake of nut. A protective effect for CAD was found when consumed more than 2 servings/week of nut. The RR of CAD was 0.96 (0.89-1.02), 0.91 (0.82-0.99), 0.85 (0.77-0.95), 0.80 (0.72-0.89), 0.75 (0.65- 0.85) and 0.70 (0.58-0.83) for 1, 2, 3, 4, 5 and 6 servings/week of nut consumption, respectively.

Conclusions: Our analysis indicated that nut consumption has a protective effect on CAD.