Follow up of young people with high casual blood pressure

High blood pressure (BP), often borderline hypertension, can be also found in adolescents. In these subjects the haemodynamic pattern, high cardiac output and normal vascular resistance, differs from that of older hypertensives. Although the risk for hypertension is higher in this group than in the general population, only a minority of them will develop sustained hypertension later in life. They can therefore be viewed as an enriched pool of future hypertensives but not as true prehypertensives. The aim of this longitudinal study was to analyse the relation between casual BP measured in high school students and in the same subjects 3 years later. In 1990, an extensive study on BP was carried out in 1062 high school students aged 18 years. Sitting BP, heart rate, weight, and body mass index (BMI) were measured in each subject. After 3 years, the 50 subjects with the highest BP level recorded in 1990 were recalled. Forty-five subjects (90%, 30 males and 15 females) agreed to undergo a second examination. They were seen as outpatients in the Hypertension Centre of our institute. BP was measured with a mercury sphygmomanometer after a 10 min rest three times in 5 min. Systolic and diastolic BP were significantly reduced after 3 years (137 +/- 13 vs 132 +/- 10 P = 0.002; 92 +/- 4 vs 85 +/- 6 P = 0.0001, mm Hg). By means of a multiple regression test, including parameters recorded in 1990, systolic blood pressure (SBP) (R = 0.53 Slg F = 0.0002) and diastolic blood pressure (DBP) (R = 0.60 Slg F = 0.0001) were shown as the main determinants of SBP, while DBP was related only to previous BMI (R = 0.37 Slg F = 0.01). The reduction of both SBP and DBP after 3 years could be explained either by a true, spontaneous decrease of BP or as a consequence of different environmental conditions during the second examination (more prolonged resting time, repeated measurements). However, data of this study demonstrate that casual SBP and DBP are the main determinants of future SBP, thus confirming the prognostic value of casual BP measurement in young people. Moreover, our data emphasises the role of BMI as the main determinant of future high DBP.