High blood pressure in the young.

Essential hypertension begins in early childhood. Current evidence suggests that those children persisting at high levels over time may be considered to have essential hypertension. The evaluation of high levels is best judged from blood pressure percentile grids representing population measurements, as long as the methods used to measure blood pressure and to generate the grids are similar. Resting, basal blood pressure measurements are more reproducible and are better for following the time course of blood pressure levels in children. Measurements should be made in an unhurried, relaxed atmosphere by trained observers using adequately lighted instruments placed at eye level and a cuff size appropriate for the child's arm length and circumference. Repeated observations and serial blood pressure measurements of growing children are necessary for judgments of abnormal levels. There is a progressive rise of approximately 1.5 mm Hg systolic and 1 mm Hg diastolic pressure per year of age, but blood pressure levels in the growing child are more closely related to height. In most instances elevated blood pressure levels in children cannot be attributed to secondary causes. Various hemodynamic and biochemical mechanisms have been identified in the early stages of hypertension, and mechanisms contributing to the development of hypertension may be of different magnitudes in black children and white children. Studies following young adults over many years have shown the predictive value of baseline blood pressure levels for subsequent hypertension. Children tracking at the high percentiles can be identified and are candidates for early intervention. The key to early prevention of essential hypertension is to influence children and adolescents to adopt lifestyles that promote good health and prevent development of cardiovascular risk factors.