Gastric cancer incidence and mortality is associated with altitude in the mountainous regions of Pacific Latin America

Abstract

In Latin America, gastric cancer is a leading cancer, and countries in the region have some of the highest mortality rates worldwide, including Chile, Costa Rica, and Colombia. Geographic variation in mortality rates is observed both between neighboring countries and within nations. We discuss epidemiological observations suggesting an association between altitude and gastric cancer risk in Latin America. In the Americas, the burden of gastric cancer mortality is concentrated in the mountainous areas along the Pacific rim, following the geography of the Andes sierra, from Venezuela to Chile, and the Sierra Madre and Cordillera de Centroamérica, from southern Mexico to Costa Rica. Altitude is probably a surrogate for host genetic, bacterial, dietary, and environmental factors that may cluster in the mountainous regions. For example, H. pylori strains from patients of the Andean Nariño region of Colombia display European ancestral haplotypes, whereas strains from the Pacific coast are predominantly of African origin. The observation of higher gastric cancer rates in the mountainous areas is not universal: the association is absent in Chile, where risk is more strongly associated with the age of H. pylori acquisition and socio-economic determinants. The dramatic global and regional variations in gastric cancer incidence and mortality rates offer the opportunity for scientific discovery and focused prevention programs.

Fig. 1

a Estimated age-standardized gastric cancer mortality rate per 100,000 in the Americas [1]; b map showing that the countries with the higher GC mortality rates follow the Andes mountains and the Sierra Madre in Central America

Fig. 2

Maps of Colombia showing in a the distribution of the Andes Cordillera and in b the distribution of gastric cancer mortality rates in the different districts of the country [11]

Fig. 3

In Venezuela, a the Andean districts with higher altitude, Tachira, Merida, and Trujillo (circle in red), and the neighbor coastal district Zulia (circle in yellow) b mortality rates in all districts of Venezuela, showing the higher gastric cancer mortality rates in the Andean districts and the very low rate in the coastal district of Zulia [12, 13]

Fig. 4

In Costa Rica, a the incidence of gastric cancer is higher in b cantons on the mountains of the Cordillera Volcanica Central [15]

Fig. 5

Relative risk of gastric cancer by altitude in Chilean counties, 1985–2002 adjusted by age, sex, and population size

Fig. 6

Seroprevalence of H. pylori in Chile is higher in regions with the higher risk for gastric cancer, particularly at young ages [9]