Hypertension screening in schools: results of the Dallas study.

The purpose of this study was to determine the prevalence of persistent blood pressure elevations in an eighth-grade population composed of three ethnic groups, and to determine the feasibility of using school health facilities for hypertension screening. Blood pressure was recorded in 10,641 subjects (90% of the total eighth-grade population) in the Dallas Independent School District. Blacks made up 46% of the population; non-Latin whites, 40.1%; and Latin-Americans, 13.9%. On the first blood pressure screening, 8.9% had systolic or diastolic pressures or both at or above the 95th percentile. Of those whose blood pressures were elevated on the first examination, 98.3% were reexamined. After the third examination, 1.2% continued to have systolic hypertension, and 0.37% diastolic hypertension. No student had diastolic pressure above 90 mm Hg on all three examinations. The prevalence of persistent hypertension was similar for the three ethnic groups. Analysis of variation in blood pressure measurements revealed that the school nurses introduced a relatively small increase in variability. These data indicate that although school screening initially identifies large numbers of students as having inconstant pressure elevations, subsequent follow-up examinations show that less than 2% have persistent hypertension.