Tracking of 24-hour and casual blood pressure: a 1-year follow-up study inadolescents

Objective Tracking of blood pressure begins in childhood but the relationsh ip between casual blood pressure in childhood and adult levels is not stron g enough to predict adult hypertension. The variability of blood pressure i n children might suggest that 24 recordings would have less consistency tha n casual readings when repeated even a relatively short time later. This st udy compares the shortterm tracking ability of casual versus 24-h blood pre ssure. Design An ambulatory blood pressure device was placed on 50 teenagers. Read ings were taken at rest and the device was then worn for approximately 24 h , which included the schoolday, The protocol was repeated 1 year later. Results The correlation coefficient for systolic readings taken 1 year late r were: 0.4 for casual, 0.6 for school, 0.6 for home, 0.5 for night-time an d 0.8 for 24-h mean systolic blood pressures. When divided into upper and l ower tertiles of systolic blood pressure the relationship between tertile r anking 1 year later was stronger for 24-h blood pressure than the casual re adings. Casual diastolic pressure was more consistent than the 24-h mean di astolic measurement. Conclusions In adolescents, in whom tracking of casual blood pressure has b een shown to be poor, 24-h mean systolic blood pressure tracks better than any other time period and significantly better than the casual systolic rea dings, This study needs to be extended and the ability of 24-h blood pressu re to track from childhood to adult life investigated. J Hypertens 2000, 18 :1193-1196 (C) Lippincott Williams & Wilkins.