Electrolytes in early primary hypertension : an epidemiological approach

The studies presented in this thesis were conducted in a population of young, non-hospitalized subjects. This opportunity was presented by the availability of a large cohort of children and young adults that had been followed up for more than seven years as part of the Epidemiologic Preventive Organization zoetermeer {EPOZ study), and of which a large body of data on blood pressure and other characteristics could be used. The basic theme of the studies was to elucidate mechanisms involved hypertension, with special electrolytes. (chapter 1) in the early pa~hogenesis emphasis on the role of of primary dietary The effect of changes in electrolyte intake in youngsters elevated blood pressure was studied in two randomized trials. with The scientific concept in evaluating the of the randomized trial is of primary importance effect of a certain characteristic, like electrolyte intake, on another characteristic, like blood Randomization garantuees internal validity of a study with pressure. regard to potential sources of bias. In addition, blinding of participants and investigators for the type of intervention during the trial reduces the possibility of distortion of the results by information bias. Randomization may be accomplished by random assignment of individuals to a certain treatment, the parallel-group design, or by randomization of treatment periods within an individual, the crossover design. Both methods were applied in studies presented in this thesis. (chapter 2)