Resting blood pressure and cardiovascular response to sympathetic stimulation in adolescents

The prevalence of significant hypertension in childhood may be higher than expected. We have measured sitting blood pressure in 168 11-yr-old children attending a pre-high school in the Neapolitan area on four occasions over a 3-month period. We have also measured blood pressure and heart rate during a mental arithmetic test and during isometric exercise. Prevalence of significant hypertension (diastolic blood pressure 82-90 mmHg) was 13% at the first visit and decreased to 6.5% at the last visit; prevalence of severe hypertension (diastolic blood pressure greater than or equal to 90 mmHg) decreased from 5.4% to 1.2% from the 1st to the 4th visit. No sex-related difference was observed. A more frequently positive family history of hypertension (50% vs 30% in the fifth and first quintile of blood pressure, respectively) and higher body weight (body mass index = 21.4 vs 19.3 kg/m2) were found in children in the 5th quintile of blood pressure distribution. Blood pressure increased during mental arithmetic by 10/13% of the resting values in the first quintile and by 6/11% in the last one during mental test; during handgrip the increase was of 20/37% and 24/46%, respectively: differences between quintiles did not reach statistical significance. These data show that about 8% of a Neapolitan sample of school population have high blood pressure levels, while no difference in vascular reactivity to sympathetic stimulation was detected in children with higher blood pressure.