title: Coffee, tea and caffeine intake and the risk of non-melanoma skin cancer: a review of the literature and meta-analysis.
abstract: Laboratory studies suggested that caffeine and other nutrients contained in coffee and tea may protect against non-melanoma skin cancer (NMSC). However, epidemiological studies conducted so far have produced conflicting results.
  
  
  
  We performed a literature review and meta-analysis of observational studies published until February 2016 that investigated the association between coffee and tea intake and NMSC risk. We calculated summary relative risk (SRR) and corresponding 95 % confidence intervals (95 % CI) by using random effects with maximum likelihood estimation.
  
  
  
  Overall, 37,627 NMSC cases from 13 papers were available for analysis. Intake of caffeinated coffee was inversely associated with NMSC risk (SRR for those in the highest vs. lowest category of intake: 0.82, 95 % CI 0.75-0.89, I2= 48 %), as well as intake of caffeine (SRR 0.86, 95 % CI 0.80-0.91, I2= 48 %). In subgroup analysis, these associations were limited to the basal cell cancer (BCC) histotype. There was no association between intake of decaffeinated coffee (SRR 1.01, 95 % CI 0.85-1.21, I2= 0) and tea (0.88, 95 % CI 0.72-1.07, I2= 0 %) and NMSC risk. There was no evidence of publication bias affecting the results. The available evidence was not sufficient to draw conclusions on the association between green tea intake and NMSC risk.
  
  
  
  Coffee intake appears to exert a moderate protective effect against BCC development, probably through the biological effect of caffeine. However, the observational nature of studies included, subject to bias and confounding, suggests taking with caution these results that should be verified in randomized clinical trials.
authors.affiliation: Cancer Risk Factors and Lifestyle Epidemiology Unit, Cancer Research and Prevention Institute (ISPO), Via delle Oblate 2, 50139, Florence, Italy. s.caini@ispo.toscana.it.
authors.forename: Saverio
authors.initials: S
authors.lastname: Caini
authors.affiliation: Department of Public Health and Infectious Diseases, Faculty of Medicine, Policlinico Umberto I, "Sapienza" University, Rome, Italy.
authors.forename: Maria Sofia
authors.initials: MS
authors.lastname: Cattaruzza
authors.affiliation: Cancer Risk Factors and Lifestyle Epidemiology Unit, Cancer Research and Prevention Institute (ISPO), Via delle Oblate 2, 50139, Florence, Italy.
authors.forename: Benedetta
authors.initials: B
authors.lastname: Bendinelli
authors.affiliation: Division of Dermatoncological Surgery, European Institute of Oncology, Milan, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Tosti
authors.affiliation: Cancer Risk Factors and Lifestyle Epidemiology Unit, Cancer Research and Prevention Institute (ISPO), Via delle Oblate 2, 50139, Florence, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Masala
authors.affiliation: Division of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Gnagnarella
authors.affiliation: Cancer Risk Factors and Lifestyle Epidemiology Unit, Cancer Research and Prevention Institute (ISPO), Via delle Oblate 2, 50139, Florence, Italy.
authors.forename: Melania
authors.initials: M
authors.lastname: Assedi
authors.affiliation: Skin Cancer Unit, Scientific Institute of Romagna for the Study and Treatment of Cancer, IRCSS, IRST, Meldola, Italy.
authors.forename: Ignazio
authors.initials: I
authors.lastname: Stanganelli
authors.affiliation: Cancer Risk Factors and Lifestyle Epidemiology Unit, Cancer Research and Prevention Institute (ISPO), Via delle Oblate 2, 50139, Florence, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Palli
authors.affiliation: Division of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Gandini
mesh_terms: D002110:Caffeine / Q000008:administration & dosage*; D002280:Basal Cell Carcinoma / Q000453:epidemiology; D003069:Coffee / Q000737:chemistry*; D006801:Humans; D064887:Observational Studies as Topic; D012307:Risk Factors; D012878:Skin Neoplasms / Q000453:epidemiology*; D013662:Tea / Q000737:chemistry*
chemical_list: D003069:Coffee; D013662:Tea; D002110:Caffeine
keywords: Caffeine; Coffee; Meta-analysis; Non-melanoma skin cancer; Tea