The influence of calcium and magnesium in drinking water and diet on cardiovascular risk factors in individuals living in hard and soft water areas with differences in cardiovascular mortality

Abstract

BackgroundThe role of water hardness as a risk factor for cardiovascular disease has been widely investigated and evaluated as regards regional differences in cardiovascular disease. This study was performed to evaluate the relation between calcium and magnesium in drinking water and diet and risk factors for cardiovascular disease in individuals living in hard and soft water areas with considerable differences in cardiovascular mortality.MethodsA random sample of 207 individuals living in two municipalities characterised by differences in cardiovascular mortality and water hardness was invited for an examination including a questionnaire about health, social and living conditions and diet. Intake of magnesium and calcium was calculated from the diet questionnaire with special consideration to the use of local water. Household water samples were delivered by each individual and were analysed for magnesium and calcium.ResultsIn the total sample, there were positive correlations between the calcium content in household water and systolic blood pressure (SBP) and negative correlations with s-cholesterol and s-LDL-cholesterol. No correlation was seen with magnesium content in household water to any of the risk factors.Calcium content in diet showed no correlation to cardiovascular risk factors. Magnesium in diet was positively correlated to diastolic blood pressure (DBP). In regression analyses controlled for age and sex 18.5% of the variation in SBP was explained by the variation in BMI, HbA1c and calcium content in water. Some 27.9% of the variation in s-cholesterol could be explained by the variation in s-triglycerides (TG), and calcium content in water.ConclusionsThis study of individuals living in soft and hard water areas showed significant correlations between the content of calcium in water and major cardiovascular risk factors. This was not found for magnesium in water or calcium or magnesium in diet. Regression analyses indicated that calcium content in water could be a factor in the complexity of relationships and importance of cardiovascular risk factors. From these results it is not possible to conclude any definite causal relation and further research is needed.

Survey of trace metals in drinking water supplied to rural populations in the eastern Llanos of Venezuela

“…This extreme scarcity of Ca and Mg can produce several diseases in populations which use this water for drinking and cooking purposes. Epidemiologic studies in Sweden (Nerbrand et al, 2003), Finland (Kousa et al, 2006) and Taiwan (Yang et al, 2006), where the minimum values found for Ca and Mg levels were much higher than the values found in our study (average of 12.5 mg/l for Ca and 3.3 mg/l for Mg in Sweden; 4.39 mg/l for Ca and 1.00 mg/l for Mg in Finland; minimum value of 25.1 mg/l for Ca in Taiwan), have shown a protective effect of Ca and/or Mg from drinking water on the risk of death from cardiovascular diseases. Statistical studies carried out in Taiwan (Yang, 1998) and Spain (Ferrándiz et al, 2004) have demonstrated the protective effect of Ca and/or Mg in drinking water against cerebrovascular mortality.…”

“…The scarcity of some base cations as calcium and magnesium in drinking water has been associated with cardiovascular diseases (Nerbrand et al, 2003;Kousa et al, 2006;Yang et al, 2006). In Spain, an increased death rate from cardiovascular and cerebrovascular diseases was reported in areas supplied with soft drinking water (Ferrándiz et al, 2004).…”

Mineral water intake reduces blood pressure among subjects with low urinary magnesium and calcium levels

“…Since then, several studies have demonstrated the same relationships, one of the last being a study from Finland in 2004 [2] and reviews have been presented [3,4]. Other studies have, however, not found such relationships or only weak associations between mineral intake and risk for cardiovascular disease [5,6]. This discrepancy may be due to an absence of causality or to variations in the populations studied regarding intake of minerals.…”

First report on the association of drinking water hardness and endothelial function in children and adolescents

“…Some studies have documented that softer water is associated with higher CVD death rates; this protective role is suggested to be because of the water Ca content [28, 29]. …”