The relationship between the hardness of treated water and cardiovascular disease mortality in South African urban areas

Area of Science:

• Environmental Health
• Cardiovascular Epidemiology

Background:

• International studies suggest a link between water hardness and cardiovascular disease (CVD) mortality.
• Previous research indicates a potential protective effect of hard water against CVD.

Purpose of the Study:

• To investigate the correlation between water hardness and CVD mortality in the South African urban white population.
• To identify specific hardness-associated factors influencing CVD mortality.

Main Methods:

• Statistical analysis of mortality data and water quality parameters.
• Correlation analysis to assess relationships between variables.
• Comparison with existing international research.

Main Results:

• A negative correlation was observed between total water hardness (as equivalent calcium carbonate mg/l) and CVD mortality (P < 0.10).
• Negative correlations were also found with hardness-associated factors: potassium (P < 0.05), sulfate (P < 0.05), chloride (P < 0.05), and manganese (P < 0.10).

Conclusions:

• Harder water supplies may be associated with lower cardiovascular disease mortality in this population.
• Specific water hardness-associated minerals warrant further investigation for their role in cardiovascular health.
• Local water quality issues and their health implications were identified.