IDENTIFYING CHILDREN AT HIGH-RISK FOR THE DEVELOPMENT OF ESSENTIAL-HYPERTENSION

Background and objectives: Because blood pressure (BP) tracks from chi ldhood to adulthood, some have recommended screening to identify child ren at high risk for the development of essential hypertension as adul ts. Others, however, have argued against this strategy because they be lieve that correlations between childhood and adulthood BP levels are too low. To address these issues, we considered prediction of adult BP from childhood levels. Design: Cohort study with follow-up of partici pants from childhood to early adulthood. Setting and participants: We ascertained BP in 337 schoolchildren from East Boston, Mass., and reex amined 317 (94%) of them 8 to 12 years later, at ages 18 to 26 years. Measurements and data analysis: On each of several visits, 1 week apar t (four for children, three for adults), we obtained three BP readings with a random-zero sphygmomanometer. To calculate correlation coeffic ients (tracking correlations) between childhood and adult BP, we assum ed a multivariate normal distribution and used on iterative maximal li kelihood approach in a longitudinal model. We then used these correlat ions in expressions for sensitivity and specificity of childhood BP as a screening test and for positive predictive value for adult BP above specified cutoff points. Results: During the 8- to 12-year interval, tracking correlations, corrected for within-person variability and adj usted for age, sex, smoking, and medication and alcohol use, were 0.55 for systolic BP and 0.44 for diastolic BP. The corresponding positive predictive values indicated that, for example, the probability that a 20-year-old man's true systolic BP will be >139 mm Hg (>90th percenti le) was 0.44, given that his observed average systolic BP at age 10 ye ars was >95th percentile (>117 mm Hg). The sensitivity of a 10-year ol d boy's systolic BP >95th percentile to defect systolic BP >139 mm Hg 40 years later was 0.17. The specificity of his BP <95th percentile at age 10 years to detect systolic BP <139 mm Hg at age 20 years was 0.9 7. For diastolic BP, predictive values and sensitivities were somewhat lower. Conclusions: After correction for within-person variability, t racking correlations from childhood to early adulthood are higher than previously reported. However, the resulting sensitivities and predict ive values for childhood BP as a screening test for adult BP are of on ly modest magnitude. These data call into question the usefulness of r outine BP measurement to identify children at high risk for the develo pment of essential hypertension.