Dietary patterns and gastric cancer risk: a systematic review and meta-analysis

Background: Declines in gastric cancer (GC) incidence and mortality have been related to improvements in diet. It is therefore important to consider dietary patterns. Design: We conducted a systematic review and meta-analysis of the literature through Medline and Embase databases. Results: We identified 16 papers, of these 9 derived dietary patterns through an a posteriori method, 5 through a priori scores, and 2 used both approaches. Eight studies that used the a posteriori approach were considered for the meta-analysis. A favorable role on GC emerged for the 'Prudent/healthy', with an odds ratio (OR) of 0.75 [95% confidence interval (CI): 0.63-0.90], for the highest versus the lowest category. Similar results emerged for separate anatomical subtypes. An unfavorable role on GC emerged for the 'Western/unhealthy' dietary pattern, with an OR of 1.51 (95% CI: 1.21-1.89). This association was weaker for the distal/NOS (not otherwise specified) category (OR = 1.36) compared with the cardia GC (OR = 2.05). Among the a priori scores, the ORs ranged from 0.2 to 0.7 for the favorable and from 1.8 to 6.9 for the unfavorable ones. Conclusion: There is a ~2-fold difference in GC risk between a 'Prudent/healthy' diet-rich in fruits and vegetables, and a 'Western/unhealthy' diet-rich in starchy foods, meat and fats.