CORRELATIONS BETWEEN WATER HARDNESS AND CARDIOVASCULAR DEATHS IN OKLAHOMA COUNTIES.

SIGNIFICANT negative correlations have been reported between the hardness of local water supplies and cardiovascular disease death rates in the states of the United States (r= -0.56, p<0.01) and the county boroughs of England and Wales (r= -0.54, p<0.0001) .1-3 Areas supplied with harder than average water for drinking purposes had lower mean age-sex-adjusted death rates from the arteriosclerotic and hypertensive cardiovascular diseases. Similar negative correlations existed for calcium and magnesium concentrations in the United States and for calcium concentrations in Great Britain. Analysis of municipal water supplies in the counties of Oklahoma showed striking differences in water hardness and specific mineral concentrations existed between the eastern third and the remainder of the state.4 Correlation of water hardness and specific mineral concentrations with cardiovascular death rates in Oklahoma counties might be expected to show a negative correlation similar to that seen on a national scale if the hardness or specific mineral concentrations of the water we drink really exert a significant effect on cardiovascular death rates. Many of the environmental and geographical variables influencing and complicating the larger studies would be reduced or eliminated in a study limited to the rural areas of a single state such as Oklahoma.