Magnesium in drinking water in relation to morbidity and mortality from acute myocardial infarction

We investigated the importance of magnesium and calcium in drinking water in relation to morbidity and mortality from acute myocardial infarction. Cases were men and women 50-74 years of age living in 18 Swedish municipalities who had suffered an acute myocardial infarction some time between October 1, 1994, and June 30, 1996. Controls were randomly selected from the same study base. We interviewed the surviving cases (N = 823) and controls (N = 853), focusing on risk factors for acute myocardial infarction. We collected individual data on drinking water levels of magnesium and calcium. We classified subjects by quartile of water magnesium or calcium levels. The total number of cases was similar in the four quartiles. The risk of death was 7.6% (95% confidence interval = 2.1-13.1) lower in the quartile with high magnesium levels (> or = 8.3 mg/liter). The odds ratio for death from acute myocardial infarction in relation to water magnesium was 0.64 (95% confidence interval = 0.42-0.97) for the highest quartile relative to the three lower ones. Multivariate analyses showed that other risk factors were not important confounders. For calcium, this study was inconclusive. The data suggest that magnesium in drinking water is associated with lower mortality from acute myocardial infarction, but not with the total incidence.     

Calcium and magnesium in drinking water and risk of death from acute myocardial infarction in Taiwan

Many studies have examined the association between cardiovascular disease mortality and water hardness. However, the results have not been consistent. This report examines whether calcium and magnesium in drinking water are protective against acute myocardial infarction (AMI). All eligible AMI deaths (10,094 cases) of Taiwan residents from 1994 to 2003 were compared with deaths from other causes (10,094 controls), and the levels of calcium and magnesium in drinking water of these residents were determined. Data on calcium and magnesium levels in drinking water throughout Taiwan have been obtained from the Taiwan Water Supply Corporation. The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. The adjusted odd ratios (95% confidence interval) were 0.79 (0.73-0.86) for the group with water calcium levels between 25.1 and 42.4 mg/L and 0.71 (0.65-0.77) for the group with calcium levels of 42.6 mg/L or more. After adjustment for calcium levels in drinking water, there was no difference between the groups with different levels of magnesium. The results of the present study show that there is a significant protective effect of calcium intake from drinking water on the risk of death from AMI.     

Calcium, magnesium, iron and zinc in drinking water and status biomarkers of these minerals among elder people from Warsaw region

The aim of this study was to estimate the influence of calcium, magnesium, iron and zinc contents in drinking water on chosen parameters of nutritional status of these minerals in 164 elder people, 75-80 age, living in Warsaw region. Blood, hair and saliva were collected to assess the calcium, magnesium, iron and zinc nutritional status, while the samples of drinking water were collected to determine these minerals in water Mineral concentrations in blood, hair saliva and water were assessment using the atomic spectrophotometer absorption method It was showed that contribution of drinking water to calcium, magnesium, iron and zinc intake was: 15%, 4%, 5%, 9%, respectively. The relationship between the contents of these minerals in drinking water and their levels in the blood, hair and saliva had low correlation coefficients. It probably showed that homeostasis was maintained in the human body and other factors such as demographic or lifestyle factors were important.     

Contribution of mineral waters to dietary calcium and magnesium intake in a French adult population

OBJECTIVE: To assess the contribution of mineral water containing different amounts of calcium and magnesium to the total dietary intakes of these minerals DESIGN: Matched case control study using data issued from the Supplementation en Vitamines et Minéraux Antioxydants (SU.VI.MAX) cohort. SUBJECTS: Subjects were water consumers-240 men and 424 women-divided into the following 4 groups (n=166 per group): regular drinkers of a calcium-rich and magnesium-rich mineral water (calcium, 486 mg/L; magnesium, 84 mg/ L), drinkers of a water classified as a moderately mineralized content (calcium, 202 mg/L; magnesium, 36 mg/L), drinkers of 2 low-mineralized waters (calcium, 9.9 to 67.6 mg/L and magnesium, 1.6 to 2 mg/L, respectively), and drinkers of tap waters. STATISTICAL ANALYSES: Quantitative data were compared using student's t test. Mean comparisons were performed in multivariate analysis by analysis of variance. RESULTS: Dietary calcium intake provided by the various food groups did not differ between the 4 consumer groups, except for calcium provided by mineral water. According to its calcium concentration, mineral water may contribute to one fourth of the total daily calcium intake. Subjects who regularly drink mineral-rich water have a calcium intake that is significantly higher (P< 10(-3)) than those drinking either low-mineral-content water or tap water. Dietary magnesium intake provided by the various food groups did not differ between the 4 consumer groups, except for magnesium provided by mineral water. Depending on the magnesium concentration of the mineral water, it contributed 6% to 17% of total daily magnesium intake. Drinkers of magnesium-rich mineral water and water with a moderate mineral content had magnesium intakes significantly (P< 10(-3)) higher than those of drinkers on low-mineralized or tap water. APPLICATIONS: Mineral-rich water may provide an important supplementary contribution to total calcium and magnesium intake. For dietetics professionals, it may provide-in place of the usual recommendations concerning the consumption of dairy products-a good way to improve calcium and magnesium intakes, particularly in subjects who don't like dairy products.     

Drinking water constituents and disease

Several epidemiological investigations over the last 50 y have demonstrated a relation between risk for cardiovascular disease and drinking water hardness or its content of magnesium and calcium. An additional parameter, first suggested in a study from Japan 50 y ago, is the acidity of the water. It is known that acid load influences the reabsorption of calcium and magnesium in the renal tubuli. Intervention studies have shown that acid-base conditions influence the homeostasis of minerals. Data from intervention studies using magnesium, calcium, and hydrogen carbonate are reviewed. It is suggested that the health effects related to drinking water found in some studies may be caused by an increased urinary excretion of minerals induced by acid conditions in the body and that drinking water should contain sufficient amounts of hydrogen carbonate to prevent this effect.     

Acid-base status affects renal magnesium losses in healthy, elderly persons

Magnesium and calcium deficiency in humans is related to a number of pathological phenomena such as arrhythmia, osteoporosis, migraine, and fatal myocardial infarction. Clinically established metabolic acidosis induces renal losses of calcium. In normal subjects, even moderate increases in net endogenous acid production (NEAP) impair renal calcium reabsorption but no information is available whether this also influences renal magnesium handling. The aim of the study was to examine the relation between NEAP and renal magnesium excretion in healthy, free-living, elderly subjects. The subjects (age 64 +/- 4.7 y, n = 85) were randomly selected from the population register in Gothenburg (Sweden). Magnesium, calcium, and potassium were measured in 24-h urine samples and NEAP was quantified as renal net acid excretion (NAE). NAE was positively correlated with excretions of magnesium (R(2) = 0.27, P < 0.0001) and calcium (R(2) = 0.30, P < 0.0001) but not potassium. When 24-h urinary magnesium excretion was adjusted for 24-h urinary potassium excretion, a biomarker for dietary potassium intake, the association between magnesium excretion and NAE remained significant (R(2) = 0.21, P < 0.0001). The significant association between potassium-adjusted magnesiuria and NAE suggests that the acid-base status affects renal magnesium losses, irrespectively of magnesium intake. Magnesium deficiency could thus, apart from an insufficient intake, partly be caused by the acid load in the body.     

Magnesium and calcium in drinking water and cardiovascular mortality

Data on the hardness of drinking water were collected from 27 municipalities in Sweden where the drinking water quality had remained unchanged for more than 20 years. Analyses were made of the levels of lead, cadmium, calcium, and magnesium. These water-quality data were compared with the age-adjusted mortality rate from ischemic heart and cerebrovascular disease for the period 1969-1978. Lead and cadmium were not present in detectable amounts except in one water sample. A statistically significant inverse relationship was present between hardness and mortality from cardiovascular disease for both sexes. Mortality caused by ischemic heart disease was inversely related to the magnesium content, particularly for the men (P less than 0.01). The rather small set of data supports results from previous studies suggesting that a high magnesium level in drinking water reduces the risk for death from ischemic heart disease, especially among men, although the possible importance of confounding factors needs further evaluation.     

Geochemistry of ground water and the incidence of acute myocardial infarction in Finland

STUDY OBJECTIVE: To examine the association of spatial variation in acute myocardial infarction (AMI) incidence and its putative environmental determinants in ground water such as total water hardness, the concentration of calcium, magnesium, fluoride, iron, copper, zinc, nitrate, and aluminium. DESIGN: Small area study using Bayesian modelling and the geo-referenced data aggregated into 10 km x 10 km cells. SETTING: The population data were obtained from Statistics Finland, AMI case data from the National Death Register and the Hospital Discharge Register, and the geochemical data from hydrogeochemical database of Geological Survey of Finland. PARTICIPANTS: A total of 18 946 men aged 35-74 years with the first AMI attack in the years 1983, 1988, and 1993. MAIN RESULTS: One unit (in German degree degrees dH) increment in water hardness decreased the risk of AMI by 1%. Geochemical elements in ground water included in this study did not show a statistically significant effect on the incidence and spatial variation of AMI, even though suggestive findings were detected for fluoride (protective), iron and copper (increasing). CONCLUSIONS: The results of this study with more specific Bayesian statistical analysis confirm findings from earlier observations of the inverse relation between water hardness and coronary heart disease. The role of environmental geochemistry in the geographical variation of the AMI incidence should be studied further in more detail incorporating the individual intake of both food borne and water borne nutrients. Geochemical-spatial analysis provides a basis for the selection of areas suitable for such research.     

The specific features of calcium, magnesium, and phosphorus supply to the population in the Primorskiĭ territory

The paper states the results of hygienic evaluation of the actual average daily dietary and drinking water intakes of calcium and magnesium in the population of the Primorye territory in 2007. The use of phosphorus as a factor that influenced the assimilability calcium and magnesium was additionally studied. The investigation used the methods of budgetary follow-up and questionnaire surveys, by applying the data on the chemical composition of foodstuffs and individual types of drinking waters. There were inadequate actual average daily intakes of calcium (22-31.1% of the normal values) and partly magnesium (574-117.5% of the normal values) and imbalance of these elements and phosphorus. Deficient intake of calcium and magnesium was most common in the residents of south-west and north-west areas of the territory. The main causes of this deficiency are the lower intake of dairy and meat products and green vegetables, the low levels of calcium and magnesium in the drinking water of its facilities, and the wide use of house water mineralization block-free filters.     

A systematic review of analytical observational studies investigating the association between cardiovascular disease and drinking water hardness

The aim of this study is to systematically review and critically assess analytical observational epidemiology studies investigating the association between levels of drinking water hardness and cardiovascular disease. We searched electronic databases and used standardised forms to extract data and assess study quality. Of 2,906 papers identified, 14 met the inclusion criteria (nine case control and five cohort studies). Of the nine case control studies, seven examined both drinking water magnesium and calcium and risk of death from cardiovascular disease. A pooled odds ratio showed a statistically significant inverse association between magnesium and cardiovascular mortality (OR 0.75 (95%CI 0.68, 0.82), p < 0.001). Only two studies reported a statistically significant effect for calcium. Substantial heterogeneity between studies made calculation of a summary estimate for drinking water calcium inappropriate. Of three cohort studies reviewed, two were of good quality. A weak suggestion that soft water was harmful in females and possibly associated with a slightly greater risk of sudden death was reported, but there was no association between water hardness and mortality from stroke or cardiovascular disease. This study found significant evidence of an inverse association between magnesium levels in drinking water and cardiovascular mortality following a meta-analysis of case control studies. Evidence for calcium remains unclear.     

A systematic review of analytical observational studies investigating the association between cardiovascular disease and drinking water hardness

The aim of this study is to systematically review and critically assess analytical observational epidemiology studies investigating the association between levels of drinking water hardness and cardiovascular disease. We searched electronic databases and used standardised forms to extract data and assess study quality. Of 2,906 papers identified, 14 met the inclusion criteria (nine case control and five cohort studies). Of the nine case control studies, seven examined both drinking water magnesium and calcium and risk of death from cardiovascular disease. A pooled odds ratio showed a statistically significant inverse association between magnesium and cardiovascular mortality (OR 0.75 (95%CI 0.68, 0.82), p < 0.001). Only two studies reported a statistically significant effect for calcium. Substantial heterogeneity between studies made calculation of a summary estimate for drinking water calcium inappropriate. Of three cohort studies reviewed, two were of good quality. A weak suggestion that soft water was harmful in females and possibly associated with a slightly greater risk of sudden death was reported, but there was no association between water hardness and mortality from stroke or cardiovascular disease. This study found significant evidence of an inverse association between magnesium levels in drinking water and cardiovascular mortality following a meta-analysis of case control studies. Evidence for calcium remains unclear.     

Smoking and myocardial infarction in women: a case-control study from northern Italy.

STUDY OBJECTIVE: To examine the relationship between smoking and myocardial infarction in women. DESIGN: Case-control study over 5 years. SETTING: Cases were women admitted to 30 coronary care units in northern Italy. Controls were admitted to the same hospitals with other acute disorders. PARTICIPANTS: These were 262 young and middle aged women with acute myocardial infarction (median age 49 years, range 24-69) and 519 controls with other acute disorders unrelated to ischaemic heart disease (median age 47 years, range 22-69). MEASUREMENTS AND MAIN RESULTS: Stratification and the Mantel-Haenszel procedure, and unconditional multiple logistic regression were used to obtain relative risks according to levels of cigarette smoking. The regression equations included terms for age, education, coffee and alcohol consumption, diabetes, hypertension, hyperlipidaemia, body mass index and oral contraceptive use. Compared to life long non-smokers, relative risk was not significantly above unity for ex-smokers but among current smokers showed a significant trend to increasing risk with larger numbers of cigarettes smoked, with risk estimates of 2.3, 5.9 and 11.0 for less than 15, 15-24 and greater than or equal to 25 cigarettes per day respectively. Smoking related risks were consistently raised across strata of hyperlipidaemia, hypertension and increased alcohol and coffee intake. CONCLUSIONS: In terms of population attributable risk, about 48% of all myocardial infarctions in young and middle aged Italian women were attributable to cigarette smoking, which is therefore by far the most important preventable determinant of the disease.     

Potassium, calcium, and magnesium intakes and risk of stroke in women

The authors examined the association between dietary potassium, calcium, and magnesium intakes and the incidence of stroke among 34,670 women 49-83 years of age in the Swedish Mammography Cohort who completed a food frequency questionnaire in 1997. The authors used Cox proportional hazards regression models to estimate relative risks and 95% confidence intervals. During a mean follow-up of 10.4 years (1998-2008), 1,680 stroke events were ascertained, including 1,310 cerebral infarctions, 154 intracerebral hemorrhages, 79 subarachnoid hemorrhages, and 137 unspecified strokes. There was no overall association between potassium, calcium, or magnesium intake and the risk of any stroke or cerebral infarction. However, among women with a history of hypertension, potassium intake was inversely associated with risk of all types of stroke (for highest vs. lowest quintile, adjusted relative risk = 0.64, 95% confidence interval (CI): 0.45, 0.92) and cerebral infarction (corresponding adjusted relative risk = 0.56, 95% CI: 0.38, 0.84), and magnesium intake was inversely associated with risk of cerebral infarction (corresponding adjusted relative risk = 0.63, 95% CI: 0.42, 0.93). Calcium intake was positively associated with risk of intracerebral hemorrhage (for highest vs. lowest tertile, adjusted relative risk = 2.04, 95% CI: 1.24, 3.35). These findings suggest that potassium and magnesium intakes are inversely associated with the risk of cerebral infarction among hypertensive women.     

Chlorination, water hardness and serum cholesterol in forty-six Wisconsin communities

The Wisconsin Heart Health Research Program measured serum lipids and other clinical parameters among residents of 46 neighbouring small communities in central Wisconsin. The purpose of the study was to determine whether distribution of serum lipids, blood pressure or thyroid hormones differed according to the chlorination of water supply, or to its calcium and magnesium content (hardness). This report examines serum lipid levels in relation to the drinking water characteristics chlorination and hardness. Variables measured on individuals included age, education level, alcohol intake, cigarette smoking, dietary fat and dietary calcium. An analysis of covariance was used to estimate effects of chlorination and hardness on each of the serum lipids, with individual variables included as covariates. Among females, serum cholesterol (SC) levels are significantly higher in chlorinated communities than in non-chlorinated communities. Community SC levels are also higher for males in chlorinated communities, on the average, but differences are smaller and not statistically significant. Low density lipoprotein (LDL) cholesterol levels follow a similar pattern to that for total SC levels, higher in chlorinated communities for females, but not different for males. On the other hand, high density lipoprotein (HDL) cholesterol community means are nearly identical in the chlorinated and non-chlorinated communities for each sex.     

Magnesium intake is not related to depression risk in Spanish university graduates

Magnesium is the second most predominant intracellular cation and it is an important cofactor in over 300 enzymatic reactions. It is a calcium antagonist and a voltage-dependent blocker of the N-methyl-D-aspartate channel, which plays a role in the entrance of calcium into the neuron. Other mechanisms also add biological plausibility to neuro-protective properties for magnesium, including an inverse association with major depression. A higher magnesium intake has been related to lower depressive symptoms. However, epidemiological evidence on this issue is scarce. Our aim was to prospectively evaluate the association between dietary magnesium intake and depression incidence in a cohort of 12,939 Spanish university graduates initially free of depression (Seguimiento Universidad de Navarra Cohort Study). Total magnesium intake was assessed with a validated, semiquantitative FFQ and incident depression was ascertained through self-reports of a new clinical diagnosis of depression done by a medical doctor and/or the habitual use of antidepressive drugs. The self-report was validated against the Diagnostic and Statistical Manual of Mental Disorders (4th edition) criteria in a subsample of the cohort. Cox regression models were used to obtain HR of incident depression during follow-up according to baseline quintiles of magnesium intake using the lowest quintile as the reference category. After a median follow-up of 6.3 y, 737 new cases of depression were identified. No association between magnesium intake and depression was found, with multivariate-adjusted HR = 1 (reference), 1.00 (95% CI: 0.78-1.27), 1.00 (0.76-1.31), 0.95 (0.70-1.30), and 1.11 (0.77-1.59) for increasing categories (quintiles 1-5) of total magnesium intake. No dose-response relationship was found (P-trend = 0.59). Results were robust through different sensitivity analyses, including nutrient density or residual models. In conclusion, our findings do not suggest an inverse association between magnesium intake and depressive disorder.     

Association of Magnesium Intake with Liver Fibrosis among Adults in the United States

Liver fibrosis represents the consequences of chronic liver injury. Individuals with alcoholic or nonalcoholic liver diseases are at high risk of magnesium deficiency. This study aimed to evaluate the association between magnesium and calcium intakes and significant liver fibrosis, and whether the associations differ by alcohol drinking status. Based on the National Health and Nutrition Examination Survey (NHANES) 2017–2018, the study included 4166 participants aged >18 years who completed the transient elastography examination and had data available on magnesium intake. The median liver stiffness of 8.2 kPa was used to identify subjects with significant fibrosis (≥F2). The age-adjusted prevalence of significant fibrosis was 12.81%. Overall total magnesium intake was marginally associated with reduced odds of significant fibrosis (p trend = 0.14). The inverse association of total magnesium intake with significant fibrosis was primarily presented among those who had daily calcium intake <1200 mg. There were no clear associations for significant fibrosis with calcium intake. Findings suggest that high total magnesium alone may reduce risk of significant fibrosis. Further studies are needed to confirm these findings.     

Drinking water hardness and chronic degenerative diseases. II. Cardiovascular diseases

Since the 1950s a causal relation between water hardness and cardiovascular diseases (CVD) in humans has been hypothesized. In order to evaluate the influence of calcium and magnesium, the minerals responsible for the hardness of drinking water, on human health, a review of all the articles published on the subject from 1980 up to today has been carried out. Many but not all geographic correlation studies showed an inverse association between water hardness and mortality for CVD. Most case-control and one cohort studies showed an inverse relation, statistically significant, between mortality from CVD and water levels of magnesium, but not calcium. Consumption of water containing high concentrations of magnesium seems to reduce of about 30-35% the mortality for CVD, but not the incidence. This inverse association is supported by clinical and experimental findings and is biologically plausible and in line with Hill's criteria for a cause-effect relationship.     

Renal effects of uranium in drinking water

Animal studies and small studies in humans have shown that uranium is nephrotoxic. However, more information about its renal effects in humans following chronic exposure through drinking water is required. We measured uranium concentrations in drinking water and urine in 325 persons who had used drilled wells for drinking water. We measured urine and serum concentrations of calcium, phosphate, glucose, albumin, creatinine, and beta-2-microglobulin to evaluate possible renal effects. The median uranium concentration in drinking water was 28 microg/L (interquartile range 6-135, max. 1,920 microg/L) and in urine 13 ng/mmol creatinine (2-75), resulting in the median daily uranium intake of 39 microg (7-224). Uranium concentration in urine was statistically significantly associated with increased fractional excretion of calcium and phosphate. Increase of uranium in urine by 1 microg/mmol creatinine increased fractional excretion of calcium by 1.5% [95% confidence interval (CI), 0.6-2.3], phosphate by 13% (1.4-25), and glucose excretion by 0.7 micromol/min (-0.4-1.8). Uranium concentrations in drinking water and daily intake of uranium were statistically significantly associated with calcium fractional excretion, but not with phosphate or glucose excretion. Uranium exposure was not associated with creatinine clearance or urinary albumin, which reflect glomerular function. In conclusion, uranium exposure is weakly associated with altered proximal tubulus function without a clear threshold, which suggests that even low uranium concentrations in drinking water can cause nephrotoxic effects. Despite chronic intake of water with high uranium concentration, we observed no effect on glomerular function. The clinical and public health relevance of the findings are not easily established, but our results suggest that the safe concentration of uranium in drinking water may be within the range of the proposed guideline values of 2-30 microg/L.     

Magnesium intake and risk of coronary heart disease among men

OBJECTIVE: Our aim in this study was to assess the relationship between magnesium intake and risk of coronary heart disease (CHD) among men. METHODS: A total of 39,633 men in the Health Professionals Follow-up Study who returned a dietary questionnaire in 1986 were followed up for 12 years. Intakes of magnesium, zinc and potassium and other nutrients were assessed in 1986, 1990 and 1994. Total CHD incidence (nonfatal myocardial infarction (MI) and fatal CHD) was ascertained by biennial questionnaire and mortality surveillance confirmed by medical record review. Standard CHD risk factors were recorded biennially. RESULTS: During 12 years of follow-up (414,285 person-years), we documented 1,449 cases of total CHD (1,021 non-fatal MI cases, and 428 fatal CHD). The age-adjusted relative risk (RR) of developing CHD in the highest quintile (median intake = 457 mg/day) compared with the lowest quintile (median intake = 269 mg/day) was 0.73 (95% CI 0.62-0.87, p for trend <0.0001). After controlling for standard CHD risk factors and dietary factors, the RR for developing CHD among men in the highest total magnesium intake quintile compared with those in the lowest was 0.82 (95% CI 0.65-1.05, p for trend = 0.08). For supplemental magnesium intake, the RR comparing the highest quintile to non-supplement users was 0.77 (95% CI 0.56-1.06, p for trend = 0.14). CONCLUSIONS: These results suggest that intake of magnesium may have a modest inverse association with risk of CHD among men.