Community differences in blood pressure levels and drinking water sodium.

In a study conducted in 1980-1981, the authors surveyed over 2000 school children in eight Iowa communities whose drinking water sodium levels varied from less than 10 to greater than 300 mg/liter. Children in grades 2-5 had four blood pressures, skinfold, height, weight, and heart rates measured while in school. The range of the difference between mean blood pressures by community was less than 4 mmHg for systolic and fourth phase diastolic. An association between blood pressure and water sodium level was not demonstrated before or after adjustment for covariates. In a subsample of over 200 households in four communities, the authors examined the relationship of blood pressures in adults to water sodium level. Blood pressure means for adults by community varied less than 4 mmHg for systolic and diastolic measurements. This variance was not explained by sodium level in the drinking water. These surveys do not substantiate previous reports of a positive association between drinking water sodium levels and blood pressure levels.