The natural history of blood pressure in childhood.

To find out whether there is a relationship between the level of blood pressure in childhood and later on in life, and whether future hypertensives can be identified early in life, we selected a random sample of 596 Dutch children. At the first examination they were 5-19 years of age. In 386 of them (65%) at least five consecutive annual blood pressure measurements were made between 1975 and 1982. The stability of a child's position in the blood pressure distribution ('tracking') was studied by linear regression of follow-up blood pressure on initial blood pressure. 'Tracking' coefficients were 0.4 to 0.6 mmHg/mmHg for systolic pressure, and 0.2 to 0.5 mmHg/mmHg for diastolic pressure after four years of follow-up. Twenty-seven per cent of the boys and 44% of the girls who were in the upper 10% of the systolic blood pressure distribution at the first examination were still there after four years. For diastolic pressure these figures were 25% and 22%, respectively. These observations indicate that there is a moderate degree of blood pressure 'tracking' in childhood. They further imply that it is impossible to detect future hypertensives early in life by measurement of blood pressure only.