Coffee and cancers of the upper digestive and respiratory tracts : meta-analyses of observational studies

Data of epidemiological studies on the relation between coffee drinking and upper aerodigestive tract cancer risk are scattered and inconclusive. We therefore conducted systematic meta-analyses of observational studies published before October 2009. Materials and methods: We combined relative risks (RR) with 95% confidence intervals (CI) for cancers of the oral cavity/pharynx (OP) and larynx, esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC), comparing the highest versus the lowest categories of coffee consumption, using random-effects models.