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

Abstract

Background: Latin America has among the highest gastric cancer incidence rates in the world, for reasons that are still unknown. In order to identify region-specific risk factors for gastric cancer, we conducted a meta-analysis summarizing published literature.

Methods: Searches of PubMed and regional databases for relevant studies published up to December 2011 yielded a total of 29 independent case-control studies. We calculated summary odds ratios (OR) for risk factors reported in at least five studies, including socioeconomic status (education), lifestyle habits (smoking and alcohol use), dietary factors (consumption of fruits, total vegetables, green vegetables, chili pepper, total meat, processed meat, red meat, fish, and salt), and host genetic variants (IL1B-511T, IL1B-31C, IL1RN*2, TNFA-308A, TP53 codon 72 Arg, and GSTM1 null). Study-specific ORs were extracted and summarized using random-effects models.

Results: Chili pepper was the only region-specific factor reported in at least five 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. The other exposures were not significantly associated. No prospective study data were identified.

Conclusion: Risk factor associations for gastric cancer in Latin America are based on case-control comparisons that have uncertain reliability, particularly with regard to diet; the specific factors identified and their magnitudes of association are largely similar to those globally recognized. Future studies should emphasize prospective data collection and focus on region-specific exposures that may explain high gastric cancer risk.

Conflict of interest statement

All authors declare no conflict of interest.

Figures

Figure 1

Flow diagram of the literature search.

Figure 2

a to c, random-effects estimates and 95% CIs of gastric cancer odds ratio (OR) associated with (A) education (highest vs. lowest level), (B) cigarette smoking (smokers vs. nonsmokers) and (C) alcohol use (drinkers vs. nondrinkers). Study-specific RRs are shown as squares, with the size of the symbol inversely proportional to the study-specific variance. Summary ORs are shown as diamonds, with the middle corresponding to the point estimate and the width representing the 95% CI.

Figure 2

a to c, random-effects estimates and 95% CIs of gastric cancer odds ratio (OR) associated with (A) education (highest vs. lowest level), (B) cigarette smoking (smokers vs. nonsmokers) and (C) alcohol use (drinkers vs. nondrinkers). Study-specific RRs are shown as squares, with the size of the symbol inversely proportional to the study-specific variance. Summary ORs are shown as diamonds, with the middle corresponding to the point estimate and the width representing the 95% CI.

Figure 2

a to c, random-effects estimates and 95% CIs of gastric cancer odds ratio (OR) associated with (A) education (highest vs. lowest level), (B) cigarette smoking (smokers vs. nonsmokers) and (C) alcohol use (drinkers vs. nondrinkers). Study-specific RRs are shown as squares, with the size of the symbol inversely proportional to the study-specific variance. Summary ORs are shown as diamonds, with the middle corresponding to the point estimate and the width representing the 95% CI.

Figure 3

a to e, random-effects estimates and 95% CIs of gastric cancer odds ratio (OR) associated with (a) total fruit consumption (highest vs. lowest category), (b) total vegetable consumption (highest vs. lowest category), (c) processed or salted meat consumption (highest vs. lowest category), (d) red meat consumption (highest vs. lowest category), and (e) Table salt use (yes vs. no). Study-specific RRs are shown as squares, with the size of the symbol inversely proportional to the study-specific variance. Summary ORs are shown as diamonds, with the middle corresponding to the point estimate and the width representing the 95% CI.

Figure 3

a to e, random-effects estimates and 95% CIs of gastric cancer odds ratio (OR) associated with (a) total fruit consumption (highest vs. lowest category), (b) total vegetable consumption (highest vs. lowest category), (c) processed or salted meat consumption (highest vs. lowest category), (d) red meat consumption (highest vs. lowest category), and (e) Table salt use (yes vs. no). Study-specific RRs are shown as squares, with the size of the symbol inversely proportional to the study-specific variance. Summary ORs are shown as diamonds, with the middle corresponding to the point estimate and the width representing the 95% CI.

Figure 3

a to e, random-effects estimates and 95% CIs of gastric cancer odds ratio (OR) associated with (a) total fruit consumption (highest vs. lowest category), (b) total vegetable consumption (highest vs. lowest category), (c) processed or salted meat consumption (highest vs. lowest category), (d) red meat consumption (highest vs. lowest category), and (e) Table salt use (yes vs. no). Study-specific RRs are shown as squares, with the size of the symbol inversely proportional to the study-specific variance. Summary ORs are shown as diamonds, with the middle corresponding to the point estimate and the width representing the 95% CI.

Figure 3

a to e, random-effects estimates and 95% CIs of gastric cancer odds ratio (OR) associated with (a) total fruit consumption (highest vs. lowest category), (b) total vegetable consumption (highest vs. lowest category), (c) processed or salted meat consumption (highest vs. lowest category), (d) red meat consumption (highest vs. lowest category), and (e) Table salt use (yes vs. no). Study-specific RRs are shown as squares, with the size of the symbol inversely proportional to the study-specific variance. Summary ORs are shown as diamonds, with the middle corresponding to the point estimate and the width representing the 95% CI.

Figure 3

a to e, random-effects estimates and 95% CIs of gastric cancer odds ratio (OR) associated with (a) total fruit consumption (highest vs. lowest category), (b) total vegetable consumption (highest vs. lowest category), (c) processed or salted meat consumption (highest vs. lowest category), (d) red meat consumption (highest vs. lowest category), and (e) Table salt use (yes vs. no). Study-specific RRs are shown as squares, with the size of the symbol inversely proportional to the study-specific variance. Summary ORs are shown as diamonds, with the middle corresponding to the point estimate and the width representing the 95% CI.

Figure 4

Random-effects estimates and 95% CIs of gastric cancer odds ratio (OR) associated with IL1RN VNTR (*2 carrier vs. *2 non-carrier). Study-specific ORs are shown as squares, with the size of the symbol inversely proportional to the study-specific variance. Summary RRs are shown as diamonds, with the middle corresponding to the point estimate and the width representing the 95% CI.