Relationship between mortality rate of stomach cancer and cerebrovascular disease and concentrations of magnesium and calcium in well water in Hyogo prefecture.

The concentration of Mg, Ca and total hardness of well and tap water were examined in 98 towns and cities in Hyogo prefecture. The annual mortality rates of stomach cancer and CVD in these areas during 1975-1979 were analyzed by the concentration of Mg and Ca in well water. The mortality rate of stomach cancer was correlated significantly positively to Mg2+/Ca2+ ratio of well water, and a similar tendency was shown in tap water. A covariance analysis indicated Mg2+ to be correlated significantly to the mortality rate of stomach cancer. Thus, it is suggested that the relatively high concentration of Mg2+ compared to Ca2+ in drinking water might be one of the causes of stomach cancer in Japanese. But the concentration of Ca2+ was correlated significantly negatively to the mortality rate of CVD.