ABSTRACT
In 1957, Kobayashi first reported a statistical correlation between the acidity of water supplies in Japan and cerebrovascular mortality [1]. Since then, numerous studies have reported an association between drinking water quality and cardiovascular disease [2-13]. Several excellent reviews of these studies have recently been published [2-8]. In general, studies have shown an inverse association between water hardness and cardiovascular disease mortality; that is, lower mortality has been found in areas where the water hardness is high. Most of the studies reporting this association were descriptive or ecologic epidemiologic studies of mortality rates in broad geographic areas having different water characteristics. Only a few studies have considered tap water exposures and possible confounding by various risk factors or have provided an estimate to measure the possible effect of a water factor [10-13]. This can be accomplished through analytic epidemiologic studies.
