Coffee consumption and risk of the metabolic syndrome: A meta-analysis

Aims. The association between coffee consumption and risk of the metabolic syndrome (MetS) remains controversial. For this reason, a meta-analysis including dose response analysis was conducted to quantitatively summarize the association between coffee intakes and MetS risk. Methods. A search was made of PubMed and the China National Knowledge Infrastructure (CNKI) for relevant articles published between 1 January 1999 and 31 May 2015. All observational studies related to the relationship of coffee consumption and risk of MetS were included in the meta-analysis. The result was estimated by a random-effects model, while the dose response relationship was assessed by a restricted cubic spline model. Results. Eleven published reports including 13 studies with a total of 159,805 participants were eligible for our meta-analysis. The aggregated result (and 95% CI) for the highest vs lowest category of coffee consumption was 0.872 (0.781-0.975). After excluding one study with a relative risk (RR) <0.300, the aggregated result (and 95% CI) was 0.889 (0.801-0.986). A non-linear relationship was found between coffee consumption and the MetS in the dose response analysis. Conclusion. This meta-analysis suggests that coffee consumption is associated with a low risk of MetS, and further studies to address the question of causality are now needed. Crown Copyright (C) 2015 Published by Elsevier Masson SAS. All rights reserved.