Mate consumption and the risk of esophageal squamous cell carcinoma: a meta-analysis

Mate, a tea-like infusion of Ilex paraguariensis, is suspected to be a risk factor for esophageal squamous cell carcinoma; however, no meta-analysis on the subject has been performed to date. A meta-analysis of studies reporting the consumption of mate in patients with esophageal squamous cell carcinoma was conducted to provide a quantitative estimate of the risk of esophageal squamous cell carcinoma associated with mate consumption. A search was conducted through MEDLINE, PubMed, EMBASE, and Current Contents Connect to April 5, 2012. We calculated pooled odds ratios (ORs) and 95% confidence intervals (CIs) using a random effects model for the risk of esophageal squamous cell carcinoma associated with exposure to mate (ever- vs. never-drinkers), as well as for the dose-dependent risk of esophageal squamous cell carcinoma associated with different levels of mate consumption (highest vs. lowest intake). Nine studies, with 1565 esophageal squamous cell carcinoma cases, met our inclusion criteria. Esophageal squamous cell carcinoma was associated with exposure to mate drink, with an OR of 2.57 and a 95% CI of 1.66-3.98. There was an increased risk of esophageal squamous cell carcinoma associated with a higher consumption of mate versus low consumption (OR 2.76, 95% CI 1.33-5.73 vs. OR 1.84, 95% CI 1.12-3.00). Heterogeneity was observed in the ever versus never and the high-consumption analyses but not in the low-consumption analysis. Publication bias was present. Mate consumption was associated with an increased risk of esophageal squamous cell carcinoma.