title: Antioxidant vitamins and risk of gastric cancer: a case-control study in Portugal.
abstract: We quantified the effect of antioxidant vitamins in gastric cancer risk, taking into account Helicobacter pylori seropositivity and overall fruit and vegetable intake. Incident cases were identified in two large hospitals in Porto, Portugal, and controls were randomly sampled among city dwellers. Food intake was assessed with a previously validated semiquantitative food-frequency questionnaire. A commercially available chromatographic immunoassay was used for the detection of immunoglobulin G antibodies. Complete questionnaire information and serum samples were available for 233 cases and 311 controls. Compared with subjects in the lowest tertile of dietary intake, the odds ratios (ORs) for those in the highest were 0.85 (95% confidence interval, CI = 0.45-1.60) for vitamin C, 1.04 (95% CI = 0.60-1.80) for vitamin E, and 1.33 (95% CI = 0.77-2.30) for provitamin A carotenoids after further adjusting for fruit and vegetable consumption. Fruit and vegetables remained an independent protective factor (OR = 0.45; 95% CI = 0.23-0.89) after further adjustment for the intake of antioxidant vitamins. H. pylori status had no significant interaction with dietary items. Factors other than H. pylori infection and intake of vitamin C and provitamin A carotenoids seem to account for the inverse association between fruit and vegetable consumption and gastric cancer.
authors.affiliation: Department of Hygiene and Epidemiology, University of Porto Medical School, Porto, Portugal. nlunet@med.up.pt
authors.forename: Nuno
authors.initials: N
authors.lastname: Lunet
authors.forename: Carmen
authors.initials: C
authors.lastname: Valbuena
authors.forename: Fátima
authors.initials: F
authors.lastname: Carneiro
authors.forename: Carlos
authors.initials: C
authors.lastname: Lopes
authors.forename: Henrique
authors.initials: H
authors.lastname: Barros
mesh_terms: D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage; D016022:Case-Control Studies; D016001:Confidence Intervals; D004032:Diet; D004034:Diet Surveys; D005260:Female; D005638:Fruit; D016481:Helicobacter Infections / Q000150:complications* / Q000453:epidemiology; D016480:Helicobacter pylori; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011174:Portugal; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D014675:Vegetables; D014810:Vitamin E / Q000008:administration & dosage; D014815:Vitamins / Q000008:administration & dosage*
chemical_list: D000975:Antioxidants; D007074:Immunoglobulin G; D014815:Vitamins; D014810:Vitamin E; D001205:Ascorbic Acid