The Relationship between Tea and Coffee Consumption and Glioma: a systematic review

Glioma is the most common form of brain tumor in adults and accounts for about 80% of the total brain malignancy. The association between several nutritional and non-nutritional factors and the incidence and prevention of glioma has been investigated in previous studies. The aim of this study is to investigate the relationship between coffee and tea consumption and the risk of glioma.
In this systematic overview, all studies published until March 2017 were reviewed using the "PubMed", "GoogleScholar" and "SCOPUS" databases using the keywords "coffee", "caffeine", "tea", "diet" and "lifestyle" for coffee and tea consumption and the keywords "glioma", "glioblastoma", "GBM", "brain tumor", "oligodendroglioma", "oligoastrocytoma", "astrocytoma" and "ependymom" for the risk of glioma.
FINDINGS: Overall, 12 studies were found to be related to the association between coffee and tea consumption and glioma. In studies that investigated the association between tea consumption and glioma, tea consumption was associated with a 25% reduction in the risk of glioma. In studies that investigated the association between total coffee and tea consumption and glioma, a 40% risk reduction was observed, consuming 5 cups or more of coffee and tea per day.
The results of the study showed that increased coffee and tea consumption is associated with lower risk of glioma.