title: An update of the WCRF/AICR systematic literature review on esophageal and gastric cancers and citrus fruits intake.
abstract: The 2007 World Cancer Research Fund/American Institute for Cancer Research expert report concluded that foods containing vitamin C probably protect against esophageal cancer and fruits probably protect against gastric cancer. Most of the previous evidence was from case-control studies, which may be affected by recall and selection biases. More recently, several cohort studies have examined these associations. We conducted a systematic literature review of prospective studies on citrus fruits intake and risk of esophageal and gastric cancers.
  
  
  
  PubMed was searched for studies published until 1 March 2016. We calculated summary relative risks and 95 % confidence intervals (95 % CI) using random-effects models.
  
  
  
  With each 100 g/day increase of citrus fruits intake, a marginally significant decreased risk of esophageal cancer was observed (summary RR 0.86, 95 % CI 0.74-1.00, 1,057 cases, six studies). The associations were similar for squamous cell carcinoma (RR 0.87, 95 % CI 0.69-1.08, three studies) and esophageal adenocarcinoma (RR 0.93, 95 % CI 0.78-1.11, three studies). For gastric cancer, the nonsignificant inverse association was observed for gastric cardia cancer (RR 0.75, 95 % CI 0.55-1.01, three studies), but not for gastric non-cardia cancer (RR 1.02, 95 % CI 0.90-1.16, four studies). Consistent summary inverse associations were observed when comparing the highest with lowest intake, with statistically significant associations for esophageal (RR 0.77, 95 % CI 0.64-0.91, seven studies) and gastric cardia cancers (RR 0.62, 95 % CI 0.39-0.99, three studies).
  
  
  
  Citrus fruits may decrease the risk of esophageal and gastric cardia cancers, but further studies are needed.
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK. s.vingeliene@imperial.ac.uk.
authors.forename: Snieguole
authors.initials: S
authors.lastname: Vingeliene
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK.
authors.forename: Doris S M
authors.initials: DS
authors.lastname: Chan
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK.|Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Dagfinn
authors.initials: D
authors.lastname: Aune
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK.
authors.forename: Ana R
authors.initials: AR
authors.lastname: Vieira
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK.
authors.forename: Elli
authors.initials: E
authors.lastname: Polemiti
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK.
authors.forename: Christophe
authors.initials: C
authors.lastname: Stevens
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK.
authors.forename: Leila
authors.initials: L
authors.lastname: Abar
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK.
authors.forename: Deborah Navarro
authors.initials: DN
authors.lastname: Rosenblatt
authors.affiliation: Division of Biostatistics, University of Leeds, Leeds, UK.
authors.forename: Darren C
authors.initials: DC
authors.lastname: Greenwood
authors.affiliation: Department of Epidemiology and Biostatistics, Faculty of Medicine, School of Public Health, Imperial College London, St. Mary's Campus, Norfolk Place, London, W2 1PG, UK.
authors.forename: Teresa
authors.initials: T
authors.lastname: Norat
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology; D016022:Case-Control Studies; D002957:Citrus; D004435:Eating; D004938:Esophageal Neoplasms / Q000453:epidemiology*; D005638:Fruit; D006801:Humans; D011446:Prospective Studies; D013274:Stomach Neoplasms / Q000453:epidemiology*
keywords: Citrus fruits; Esophageal cancer; Gastric cancer; Meta-analysis; Systematic literature review