Risk factors for gastric cancer in Latin America: a meta-analysis

Background: Gastric cancer represents the second leading cause of cancer death worldwide. Latin America has among the highest incidence rates, which vary across populations. In order to identify region-specific risk factors that could be amenable to tailored interventions we conducted a meta-analysis summarizing the published literature on gastric cancer risks in Latin American populations. We contrasted our findings with global meta-analyses, which generally overlook regional studies included.

Methods: PubMed and regional literature databases were searched for studies evaluating risk factors for gastric cancer published up to December 2011. We calculated summary odds ratios using the random-effects method of DerSimonian for factors reported in at least five studies. Between-study heterogeneity was assessed using the Q test and quantified with the I2 statistic, Galbraith plots were used to visually identify studies which were major contributors to moderate or high heterogeneity. Sensitivity analyses excluding such studies were performed to assess the influence. Publication bias was investigated by visual inspection of Begg’s funnel plots and formally tested using Egger’s regression asymmetry method.

Results: Searches yielded a total of 29 independent case-control studies. Consistent with multifactorial pathogenesis, smoking, alcohol use, high consumption of red meat or processed meat, excessive salt intake, and carriage of IL1RN*2 were each associated with a moderate increase in gastric cancer risk. Conversely, higher levels of education, fruit consumption, and total vegetable consumption were each associated with a moderately decreased risk. Chili pepper was the only region-specific factor reported in at least five studies.

Conclusion: We identified risk factors for gastric cancer in Latin American countries that are similar to those identified globally. Most of our summarized risk estimates were moderate in magnitude, suggesting that additional risk factors contributing to the high incidence of gastric cancer in Latin America are yet to be recognized. Future studies should emphasize prospective data collection and focus on region-specific exposures that may explain high gastric cancer risk.