Hard drinking water does not protect against cardiovascular disease: new evidence from the British Regional Heart
Richard W Morris1, Mary Walker, Lucy T Lennon
1Department of Primary Care & Population Sciences, University College London, London, UK. r.morris@pcps.ucl.ac.uk
Insights
This study found that hard drinking water, calcium, and magnesium do not significantly protect against cardiovascular disease or coronary heart disease. Findings do not support adding minerals to desalinated water for heart health.
Area of Science:
- Epidemiology
- Cardiovascular Health
- Environmental Health
Background:
- Previous research suggested hard drinking water, rich in calcium and magnesium, may offer cardiovascular protection.
- This hypothesis has implications for public health initiatives, particularly concerning water treatment and supplementation.
Purpose of the Study:
- To investigate the association between drinking water hardness and individual calcium/magnesium intake with cardiovascular disease (CVD) and coronary heart disease (CHD) incidence and mortality.
- To evaluate the evidence supporting the protective effects of water minerals on cardiovascular health.
Main Methods:
- A prospective study of 7,735 men aged 40-59 from 24 British towns with varying water hardness.
- Individual water hardness, calcium, and magnesium intake were assessed via questionnaires and tap water analysis.
- Participants were followed for 25 years for major coronary heart disease (CHD) and stroke events, and CHD mortality.
Main Results:
- A weak, non-significant inverse association was observed between water hardness and cardiovascular disease incidence (HR 0.96, P=0.08).
- No significant association was found between water hardness and CHD incidence or mortality.
- Individual magnesium intake showed a positive association with CHD incidence (HR 1.10, P=0.045), while calcium intake was unrelated to cardiovascular outcomes.
Conclusions:
- High water hardness, calcium, or magnesium intake do not appear to offer significant protection against coronary heart disease or cardiovascular disease.
- Current findings do not support public health initiatives aimed at increasing calcium and magnesium in desalinated water for cardiovascular benefits.
Background:
It has been previously suggested that hard drinking water in general, and in particular high calcium and magnesium intake from drinking water, protect against cardiovascular disease.
Design:
Prospective study of men from 24 British towns, with widely differing levels of hardness in drinking water.
Methods:
A total of 7,735 men aged 40-59 years were recruited during 1978-1980. Estimates of town-level water hardness were available and tap water samples, taken from 947 participants who also answered a questionnaire about water consumption, were used to calculate individual calcium and magnesium intakes. Men were followed for incident of major coronary heart disease (CHD) and stroke, and CHD mortality for 25 years.
Results:
Water hardness varied from 0.27 to 5.28 mmol/l in the 24 towns. A weak inverse association was found between water hardness and incidence of cardiovascular disease (CVD) [hazard ratio (HR), 0.96 per two-fold increase, 95% confidence interval (CI), 0.91-1.01, P=0.08 after adjustment for age and seven established coronary risk factors]. No association was observed with CHD incidence (adjusted HR, 0.99, 95% CI, 0.94-1.04, P=0.62) or mortality (adjusted HR, 0.96, 95% CI, 0.90-1.02, P=0.18). Individual magnesium intake showed a positive, rather than an inverse, association with CHD incidence (adjusted HR, 1.10 per two-fold increase, 95% CI, 1.01-1.20, P=0.045); individual calcium intake was unrelated to CHD or CVD end points.
Conclusions:
This study suggests that neither high water hardness, nor high calcium or magnesium intake appreciably protect against CHD or CVD. Initiatives to add calcium and magnesium to desalinated water cannot be justified by these findings.
Related Concept Videos
01:26Coronary Artery Disease IV: Preventive Measures
01:20Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
01:26Atherosclerosis III: Management
01:23Assessment of the Cardiovascular System I: Subjective Data
Initial Enquiry
Ask the patient about their primary concern and thoroughly explore all reported symptoms.
Medical History
Investigate past illnesses affecting the cardiovascular system, such as angina, anemia, rheumatic fever, congenital heart disease, stroke, thrombophlebitis, dysrhythmias, varicosities
Inquire about symptoms...
01:22Heart Failure Drugs: Diuretics
01:30Coronary Artery Disease I: Introduction