Prevalence of hypertension in 9- to 10-year-old Icelandic school children

Abstract

The purpose of the study was to investigate blood pressure (BP) distribution, prevalence of hypertension, and correlation between BP and body mass index (BMI) in 9- to 10-year-old Icelandic children. Two manual and two automated BP measurements were performed in 1071 Icelandic children. Children with elevated BP underwent a second BP screening, and a third screening was performed if the BP was elevated at the second visit. Hypertension was defined as BP ≥95th percentile at all three visits. White-coat hypertension was diagnosed in hypertensive children with normal 24-hour ambulatory BP. Of 970 children with complete data, 489 were girls (50.4%). The mean BP was 111/63 mm Hg in girls and 112/64 mm Hg in boys (P<.001). The prevalence of elevated BP was 13.1%, 6.0%, and 3.1% after the first, second, and third screen, respectively. The prevalence of sustained hypertension was 2.5% and an additional 0.6% had white-coat hypertension. A significant correlation between BMI and BP was observed (r=0.338, P<.001) and 8.6% of the obese children had hypertension. The prevalence of hypertension in 9- to 10-year-old Icelandic children is lower than indicated in recent reports and is associated with obesity.

Figure 1

Distribution of systolic (panel A) and diastolic (panel B) blood pressure in 970 nine‐ to 10‐year‐old Icelandic children at the first blood pressure screening session. Blood pressure percentiles were defined according to normative blood pressure data published by the National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. ¹⁶

Figure 2

Correlation between body mass index (BMI) and mean systolic blood pressure (Spearman’s r=0.34, P≤.001). The open circles and dashed line represent girls and the black dots and solid line represent boys. The lines indicate fit by nonparametric smoothing.

Figure 3

Prevalence of elevated blood pressure at the first, second, and third screening sessions, categorized by body mass index (BMI) percentiles (Somers’ d test for linear trend; first screening, P<.001; second screening, P=.002; third screening, P=.007).