Statistics on the community level have revealed an increased mortality from cardiovascular diseases, especially stroke, among women in the community of Strömstad situated in the northern part of the County of Göteborg and Bohus near the Norwegian border. Based on prevalence data from a population study in Strömstad, to which all women aged 45-64 were invited and 86% attended, it was, however, concluded that history of cardiovascular diseases including stroke were not more common in Strömstad than in Gothenburg and Copenhagen. Traditionally accepted risk factors could not explain an increased mortality from these diseases in Strömstad, as these factors did not differ between Strömstad and a number of other communities, with which Strömstad was compared. It seems reasonable also to take other factors into consideration in order to explain the increased mortality, e.g. socio-economic factors and softness of the drinking water.