Change of blood pressure over five years in childhood and adolescence.

We compared blood pressure (BP) values, measured at a five year interval, in 2,777 boys and girls aged 4-18 years. BP values were converted into height and sex adjusted standard deviation unit scores. Correlation coefficients were significant but low for systolic BP score: 0.19 in boys and 0.15 in girls, and were even lower for diastolic BP score. These correlations are weaker than those observed for overall BP values (boys: 0.33, girls: 0.23), weight (0.82, 0.75) and height (0.87, 0.80). The probability of remaining in a high percentile (greater than 95th) is low since only 14 p. cent of boys and 8 p. cent of girls whose first systolic BP value was greater than the 95th percentile were still in this range five years later. Probability was still weaker for diastolic BP. BP tracking exists but would appear to be weak to permit early detection of future hypertensives, and does not justify preventive measures other than advice on diet and way of life.