Climate, Water Hardness and Coronary Heart Disease*7

GEOORAPIIIC variation in coronary heart disease mortality within the United States has been shown to be considerable [I]. These differences appear to be real, and not attribu~ble to varying patterns of medical practice or death ~~~~tion. Other workers [2-4] have shown that there are marked differences in coronary disease rates even within a given state. The reason behind these differences may be a key to the mystery of coronary disease etiology [5]. Many environmental factors have been proposed as possible explanations of these differences. These include various aspects of urba~zation, population density and socio-economic status, altitude, air pollution and water supply. Even soil type has been found to have a possible association with death rates due to coronary heart disease [3].