Correlation between water hardness and cardiovascular
diseases in Mostar city, Bosnia and Herzegovina
Nevenka J. Knezovic ´, Mustafa Memic ´, Mirela Mabic ´, Jasna Huremovic ´
and Ivanka Mikulic ´
ABSTRACT
The aim of this study was to determine the association of cardiovascular disease (CVD) of selected
human subjects with the hardness of water they consume. Laboratory testing of physical and
chemical parameters of water were made using standardized methods: Standard Methods 19th edn,
1995 (APHA, AWWA & WEF, Washington, DC), and ISO 7888:1985, ISO 10523:1998. Pearson’s chi-
squared test was used for the statistical analysis of data, with the significance level of 0.05. The
obtained data were analysed using the statistical program SPSS 16.0. The study sample consisted of
1,021 individuals divided into two groups: soft water consumers, 603 individuals, and, hard water
consumers, 618 individuals. Results indicate that a statistically significant (χ
2
¼ 5.315; df ¼ 1; p ¼
0.021) number of individuals with CVD drink soft water. The prevalence of CVD in the age group 45–
60 years in the study area where soft water is consumed was 21.3% and in the study area where hard
water is consumed the prevalence of CVD was 13.7%. The summary results indicate significant
correlation between the prevalence of CVD in the population group who drink soft water. The value
of the relative risk is 1.127.
Mustafa Memic ´ (corresponding author)
Jasna Huremovic ´
Department of Chemistry, Faculty of Science,
University of Sarajevo,
Zmaja od Bosne 33-35,
71000 Sarajevo,
Bosnia and Herzegovina
E-mail: m_memic@yahoo.com
Nevenka J. Knezovic ´
Ivanka Mikulic ´
Faculty of Medicine,
University of Mostar,
Kralja Petra Krešimira IV b.b.,
88 000 Mostar,
Bosnia and Herzegovina
Mirela Mabic ´
Faculty of Economics,
University of Mostar,
Matice hrvatske bb, 88 000 Mostar,
Bosnia and Herzegovina
Key words | cardiovascular disease, hard water, risk factors, soft water
INTRODUCTION
Cardiovascular disease (CVD) is a leading cause of death in
western countries. There are over 300,000 sudden deaths
per year in the United States caused by CVD. Because of
the importance of CVD, major efforts have been made to
identify risk factors and to take steps to reduce these risks
(Frost ). Almost 50 years have passed since the publi-
cation of the first papers suggesting an inverse association
between the hardness of drinking water and cardiovascular
mortality in Japan and in the USA (Catling et al. ). This
was followed by a number of studies in different countries
where water hardness, and later the concentration of mag-
nesium and calcium, were used as a criterion for water
quality. Several epidemiological investigations over the last
50 years have demonstrated a relation between risk of
CVD development and hardness of drinking water or its
content of Mg and Ca (Rylander ). Available data
from statistical reports of the Bosnia and Herzegovina
(B&H) Institute of Public Health have shown that the
death rate from CVD in B&H covers 50% of all causes of
mortality (Institute for Public Health Federation B&H
). Drinking water plays an important role in human
health and well-being.
Hardness is an important water quality parameter, since
increased water hardness limits its drinking suitability, as
well as other purposes. Water hardness is a measure of the
number of cations dissolved in the water, it is therefore,
related to dissolved solids. The higher the number of dissolved
cations the ‘harder’ the water will be. The most common
cations found in water are both Ca and Mg, while iron, stron-
tium, and manganese also contribute to hardness and are
seldom present in appreciable amounts. Hardness is usually
reported as an equivalent amount of calcium carbonate
(CaCO
3
)(Meena et al. ). An increasing body of evidence
indicates that hardness of drinking water and elevated
817 © IWA Publishing 2014 Journal of Water and Health | 12.4 | 2014
doi: 10.2166/wh.2014.129
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