The influence of naturally and artificially elevated levels of sodium in drinking water on blood pressure in school children.

Building on prior work on sodium (Na) in drinking water and its effects on blood pressure (BP), two variations of the initial University of Massachusetts studies were carried out in other locations using the same methodology as the original investigations. A Texas/Oklahoma study compared the BP of 7th graders in two economically similar communities whose drinking water Na levels were 25 mg/L and 275 mg/L, a difference 2 1/2 times that in the original University of Massachusetts studies. A second study in Ohio, within only one community, compared the BP's of the 7th graders with a home water softener to their peers drinking the same water unsoftened (400 ppm total hardness). Although both studies have some complicating factors, the preliminary results indicate some effect of elevated Na in drinking water upon blood pressure in normotensive children.