TY - JOUR T1 - Letter: Ischemic heart disease, water hardness and myocardial magnesium JF - Canadian Medical Association Journal JO - CMAJ SP - 199 LP - 203 VL - 113 IS - 3 AU - T. W. Anderson AU - L. C. Neri AU - G. B. Schreiber AU - F. D. Talbot AU - A. Zdrojewski Y1 - 1975/08/09 UR - http://www.cmaj.ca/content/113/3/199.abstract N2 - In 54 cases of accidental death in cities with water hardness of 60 parts per million (ppm) or less, the mean myocardial magnesium concentration was 918 mug/g of dry tissue. This was 7% lower than the corresponding figure of 982 mug/g among 29 cases of accidental death in cities with water hardness of 300 ppm or more, and this difference was significant (P less than 0.01). There were no significant differences between the cities with soft and hard water in the mean myocardial concentrations of calcium, zinc, copper, chromium, lead or cadmium. These results are compatible with the belief that the relatively high death rates in some soft-water areas may be due to a suboptimal intake of magnesium, and that water-borne magnesium exerts a protective effect on the residents of hard-water areas. ER -