ABSTRACT

In this systematic review and dose-response meta-analysis, we aim to assess whether coffee and tea consumption is related to the risk of glioma. We performed a systematic literature search using PubMed, Embase, Scopus, and the EuropePMC up until 1st October 2020. Exposures in this study were coffee and tea consumption. The main outcome of this study was the incidence of glioma. This study compares the association between the exposure of coffee and tea with the incidence of glioma, the results are reported in Relative Risks (RRs). There are 12 unique studies comprising of 1,960,731 participants with 2,987 glioma cases. Higher coffee consumption was associated with a statistically non-significant trend towards lower risk of glioma (RR 0.77 [0.55, 1.03], p=0.11; I2: 75.27%). Meta-regression showed that the association between coffee and glioma was reduced by smoking (p=0.029). Higher tea consumption was associated with the lower risk of glioma (RR 0.84 [0.71, 0.98], p=0.030; I2: 16.42%). Sensitivity analysis by removal of case-control studies showed that higher coffee consumption (RR 0.85 [0.72, 1.00], p=0.046; I2: 0%) and higher tea consumption (RR 0.81 [0.70, 0.93], p=0.004; I2: 0%, Pnon-linearity=0.140) were associated with lower risk of glioma. Dose-response meta-analysis showed that every 1 cup of coffee per day decreases the risk of glioma by 3% (RR 0.97 [0.94, 0.99], p=0.016, Pnon-linearity=0.054) and every 1 cup of tea per day decreases the risk of glioma by 3% (RR 0.97 [0.94, 1.00], p=0.048). This meta-analysis showed apparent association between coffee and tea intake and risk of glioma.