A longitudinal study of blood pressure in a national survey of children.

Blood pressure changes over a three- to four-year period were studies in a cohort of 2,168 children examined during the US Heath Examination Survey. The sample used is a representative subset of a national probability sample. Significant positive correlations between initial and follow-up blood pressures were observed. In addition, relatively obese children tended to demonstrate higher blood pressures within age-race-sex specific subgroups.