A systematic review and a dose-response meta-analysis of coffee dose and nonalcoholic fatty liver disease

Objective: Nonalcoholic fatty liver disease (NAFLD) is the most predominant chronic liver disease worldwide. Effect of coffee on NAFLD risk and its potential dose-response patterns were explored in the study. Design: PubMed, Web of Science, MEDLINE, Cochrane and Embase were searched up to 10 April 2018. We performed pair-wise meta-analysis of <1 cup per day vs. 1-2 cups per days or >2 cups per day to pool the relative risks (RRs) and corresponding 95% confidence intervals (CIs). And dose-response analysis was used to estimate relationship of NAFLD occurrence with coffee intake. Results: Seven articles were included with 4825 cases and 49,616 non-cases. Compared with <1 cup, 1-2 cups or >2 cups of coffee consumption per day were not significantly associated with NAFLD occurrence, and RR were 0.97 (95% CI: 0.85-1.11) and 0.88 (95%CI: 0.72-1.06). However, the summary RR of the highest versus lowest coffee consumption was 0.94 (95% CI: 0.92-0.97). Dose-response meta-analysis presented a non-linearity curve relationship of coffee and NAFLD occurrence while coffee consumption >3 cups per day reduced NAFLD significantly. Conclusion: Coffee intake level more than 3 cups was observed lower risk of NAFLD than <2 cups per day. Although the risk of NAFLD was inversely associated with coffee consumption, while relevance may not be very close and more observational studies would be needed to verify the relationship of coffee and NAFLD. (C) 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.