Fruit and vegetable consumption and gastric cancer by location and histological type: case-control and meta-analysis

The available information favours a greater impact of environmental exposures on intestinal type gastric cancer, and risk factors for the cardia and distal stomach cancers also appear to be different. We aimed to estimate the association between fruit and vegetable intake and gastric cancer, by location and histological type. We performed a population-based case-control study and a meta-analysis of studies addressing this issue. Incident cases (n=305) were identified in two large teaching hospitals (Porto, Portugal), and controls were randomly sampled among city dwellers (n=1129). Published studies were searched through PubMed, and effects were combined with random effects meta-analysis. In our case-control study, the odds ratio (OR) for the comparison of the highest vs. lowest tertile of fruit consumption was 0.47 [95% confidence interval (CI): 0.21-1.05] for cardia, 0.53 (95% CI: 0.35-0.80) for non-cardia cancer, 0.36 (95% CI: 0.20-0.62) for intestinal, and 1.00 (95% CI: 0.53-1.90) for the diffuse histological type. For vegetables, the corresponding OR was 0.59 (95% CI: 0.26-1.35), 0.85 (95% CI: 0.58-1.26), 0.95 (95% CI: 0.57-1.57), and 0.60 (95% CI: 0.32-1.14). In meta-analysis, considering fruit consumption (highest vs. lowest category), the combined OR was 0.58 (95% CI: 0.38-0.89) for cardia, 0.61 (95% CI: 0.44-0.84) for non-cardia, 0.49 (95% CI: 0.33-0.72) for intestinal type, and 0.82 (95% CI: 0.57-1.20) for diffuse type. Vegetables also decreased the risk of cardia (OR=0.63, 95% CI: 0.50-0.79), non-cardia (OR=0.75, 95% CI: 0.59-0.95), intestinal (OR=0.61, 95% CI: 0.44-0.86), and diffuse type (OR=0.67, 95% CI: 0.44-1.01). Fruit or vegetable intake was associated with a decreased risk of gastric cancer regardless of the anatomical location and the histological type, although dietary intake had a more clear-cut protective effect on intestinal type cancers.