Myocardial infarction and water hardness in the WHO myocardial infarction registry network

The negative association between water hardness and cardiovascular disease found by several authors in different countries has also been found in the present investigation. All cases of myocardial infarction were registered in a standardized way at 15 WHO Collaborating Centres in Europe; information on the hardness of drinking water used by the population studied was also collected. Higher rates of myocardial infarction were usually found in towns served by softer water.