Ambulatory blood pressure (ABP) monitoring is increasingly used to evaluate the blood pressure of children and adolescents. The upper normal ABP values in the pediatric age group are still unknown, because reference values based on a sufficiently high number of healthy children have not yet been published. In this multicenter trial, we pooled ABP records of 1141 healthy children and adolescents with a body height between 115 and 185 cm. The study was carried out by seven centers according to a common protocol. The 50th percentile for 24-hour systolic ABP increased moderately with height, from 103 to 113 mm Hg in girls and from 105 to 120 mm Hg in boys. The 50th percentile for diastolic 24-hour means was 66 +/- 1 mm Hg, irrespective of height or gender. Diastolic daytime means were 73 +/- 1 mm Hg, which is remarkably high compared with reference values for casual blood pressure. The mean nocturnal systolic and diastolic ABP (midnight to 6 AM) was 13% +/- 6% and 23% +/- 9% lower compared with the daytime means (8 AM to 8 PM), respectively. This multicenter study provides well-based limits of normal ABP in mid-European children.

Ambulatory blood pressure monitoring (ABPM) was performed in 564 healthy schoolchildren during normal circadian activities. The data of two cohorts (155 boys and 139 girls aged 9–13 years and 184 boys and 168 girls with a body height between 120 and 155 cm) are presented. From the age of 9 to 13 years the mean 24-h systolic/diastolic blood pressure (SBP/DBP) increases from 107±9/ 66 ± 7 mmHg to 115 ± 13/68 ± 9 mmHg in boys and from 104 ± 5/64 ± 6 mmHg to 109 ± 8/65 ± 9 mmHg in girls. When related to body height the values rise from 105 ± 6/ 64 ± 6 mmHg at 120 cm to 113 ± 8/67 ± 7 mmHg at 155 cm in boys and from 100±7/65±7 mmHg to 112±9/ 66 ± 9 mmHg in girls. In comparison with the casual blood pressure data obtained from European studies, the presented ABPM values (daytime BP) are higher throughout, which may be explained by the increased activity during daytime with ABPM. There is a mean difference of 4.4 mmHg in boys and of 3.0 mmHg in girls for SBP and of 10.8 mmHg in boys and of 9.0 mmHg in girls for DBP when related to age. In relation to body height, there is a mean difference of 4.4 mmHg in boys and of 3.5 mmHg in girls for SBP and of 10.9 mmHg in boys and of 10.5 mmHg in girls for DBP. We conclude that standards derived from casual blood pressure measurements should not be used for the evaluation of ABPM data.