Aggregation of blood pressure in the families of children with labile high systolic blood pressure. The Muscatine Study.

The aggregation of systolic blood pressure, diastolic blood pressure, and heart rate is compared among the relatives of three groups of index children: children with low systolic blood pressure (less than the 5th percentile), middle range systolic blood pressure (between the 5th and 95th percentiles), or labile high blood pressure (above the 95th percentile when first sampled but below the 95th percentile when resampled four to six months later). Both systolic and diastolic blood pressures aggregate more strongly in the families of children with labile high systolic blood pressure than in the families of children with middle or low range systolic blood pressure. The degree of aggregation of heart rate does not differ among the three groups. Since blood pressures aggregate so strongly in families of children with labile high systolic blood pressure, study of these children and their families may yield important information about the etiology of hypertension.