Abstract
Blood pressure was measured in 946 Danish schoolchildren aged 7-18 yr. The children were randomly selected and serve as an urban reference population. Blood pressure was measured in 52 different schools with the same random-zero-sphygomanometer, and all pressures were measured by the same person, under standardized conditions, to eliminate possible sources of error and uncertainties. For both sexes an age-dependent significant increase in systolic and diastolic blood pressure was observed. For the systolic and the diastolic pressures, significant differences in blood pressure measured before and after blood testing were observed.