Relationship between mineral and trace element concentrations in drinking water and gastric cancer mortality in Japan

It is well known that the incidence and mortality from gastric cancer in Japan are the highest in the world. This is thought to be due, in part, to dietary habit, including a high salt intake. There are, however, no epidemiological reports to describe the relationship between ingestion of mineral and trace elements and gastric carcinogenesis. In this study, we determined the concentrations of 14 elements in drinking water from 34 water treatment plants in Aomori Prefecture, Japan, and studied how element concentrations were geographically associated with gastric cancer mortality rate. Gastric cancer mortality was calculated from the data of the Annual Aomori Health Report. Multiple regression analysis (stepwise method of decreasing the number of variables) was performed by using age-adjusted mortality of gastric cancer by gender as objective variables and each element concentration as an explanatory variable. The standardized partial regression coefficient was significant in men for zinc (-0.59, P = 0.004), lead (1.01, P = 0.013), strontium (1.23, P = 0.007), and selenium (-1.62, P = 0.004), whereas it was significant in women for lead (-0.65, P = 0.022), strontium (0.51, P = 0.035), and gold (0.70, P = 0.019). It is suggested that selenium and zinc may aid in the prevention of gastric carcinogenesis. However, the significant relationship of sodium (a component of salt) to gastric carcinogenesis was not observed, although many previous epidemiological studies in Japan have shown this relationship.