title: Allium vegetable intake and gastric cancer: a case-control study and meta-analysis.
abstract: METHODS
  To provide new epidemiological data and summarize evidence on the association between allium vegetable intake and gastric cancer risk.
  
  
  RESULTS
  Data were from an Italian case-control study including 230 cases and 547 controls. Odds ratios were derived using multiple logistic regression. We combined results from all published studies using random-effect models. In our case-control study, the odds ratios were 0.59 (95% confidence interval, CI, 0.25-1.41) for ≥2 portions of onion per week, 0.69 (95% CI, 0.41-1.15) for high garlic intake, and 0.70 (95% CI, 0.39-1.28) for frequent use of both onion and garlic. Besides our study, 22 case-control and four cohort studies were included in the meta-analyses (>10 000 cases). The pooled relative risks for the highest versus lowest intake category were 0.78 (95% CI, 0.67-0.91) for allium vegetables (ten case-control and four cohort studies), 0.60 (95% CI, 0.47-0.76) for garlic (12 case-control studies), and 0.55 (95% CI, 0.41-0.73) for onion (13 case-control studies). The pooled relative risk for high allium vegetable intake from the four cohorts was 1.02 (95% CI, 0.88-1.18).
  
  
  CONCLUSIONS
  High allium vegetable consumption is likely to reduce gastric cancer risk. This evidence is derived mainly from case-control studies. Further data from large cohorts are desirable for conclusive confirmation.
authors.affiliation: Department of Epidemiology, IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Turati
authors.forename: Claudio
authors.initials: C
authors.lastname: Pelucchi
authors.forename: Valentina
authors.initials: V
authors.lastname: Guercio
authors.forename: Carlo
authors.initials: C
authors.lastname: La Vecchia
authors.forename: Carlotta
authors.initials: C
authors.lastname: Galeone
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000490:Allium; D016022:Case-Control Studies; D005260:Female; D005737:Garlic; D006801:Humans; D007558:Italy; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D019697:Onions; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D014675:Vegetables; D055815:Young Adult
keywords: Allium vegetables; Diet; Garlic; Gastric cancer; Onion