Coffee consumption and risk of nonmelanoma skin cancer: a dose-response meta-analysis

Several epidemiological studies have evaluated the associations between coffee consumption and the risk of skin cancer; however, the results were not conclusive. This systematic review and meta-analysis of the cohort and case-control studies was carried out to determine the association between coffee intake and the risk of nonmelanoma skin cancer. Studies were identified by searching the PubMed and MEDLINE databases (to November 2015). Study-specific risk estimates were pooled under the random-effects model. We separately estimated the relative risk of the three conditions, for exposure to different doses of coffee consumption, kind of study design, and analysis restricted to the basal cell carcinoma type. The summary relative risks for nonmelanoma skin cancer were 0.96 [95% confidence interval (CI): 0.92-0.99] for one cup of coffee, 0.92 (95% CI: 0.88-0.97) for one to two cups of coffee, 0.89 (95% CI: 0.86-0.93) for two to three cups of coffee, and 0.81 (95% CI: 0.77-0.85) for more than three cups of coffee per day, respectively. This meta-analysis suggested that caffeinated coffee might have chemopreventive effects against basal cell carcinoma dose dependently. However, other prospective studies are warranted to confirm these effects.