Water hardness zoning of Isfahan Province, Iran, and its relationship with cardiovascular mortality, 2013-2015

BACKGROUND: Cardiovascular disease (CVD) is one of the common diseases and today, it is considered as not only an important cause of mortality but also a significant aspect of health geography. The evidence presented in the literature indicates that hard water may reduce the cases of sudden death caused by CVDs because drinking water contains significant amounts of calcium and magnesium, which play a crucial role in the electrical activity of heart. Hence, the present study aimed at investigating the relationship between water hardness and CVD mortality rate in Isfahan, Iran. METHODS: In this ecological study, the available data regarding the cardiovascular mortality rate and water hardness have been used. Preparation of zoning map has been conducted using the Geographic Information System (GIS) software considering Inverse Distance Weighting (IDW) interpolation models. Moreover, statistical analysis has been conducted using SPSS software. RESULTS: A reverse relationship was observed between cardiovascular mortality rate and water hardness. However, the observed relationship was not statistically significant (2013: r = -0.066, 2014: r = -0.155, 2015: r = -0.051, P > 0.050). CONCLUSION: The results of mapping with GIS and statistical analysis with SPSS both indicated a non-significant inverse relationship between the water hardness and CVDs. However, lack of a significant relationship highlights the necessity of conducting similar studies involving larger sample sizes and wider areas of investigation to present a definitive and generalizable result.