International collaborative study on juvenile hypertension. 1. Study procedures and screening data.

The study procedures and the results of blood pressure screening from 8 centres are reported. Data are also presented on age, sex, sexual maturity for girls, height, weight, Quetelet's index, smoking, and use of antihypertensive drugs for 92.1% of the 18 609 children born in 1964 in the 8 districts and surveyed in 1977. The girls who had reached sexual maturity had the highest means for blood pressure, height, weight, and Quetelet's index. The proportion of girls who had attained menarche differed geographically. Certain differences were found among the 8 centres in the variables measured, but when age-specific comparisons were made most of the differences in the variables disappeared. Nevertheless a lower systolic blood pressure and height and a higher pulse rate were observed in Havana, Cuba, than in the European cities. Using multivariate analysis, height, weight, pulse rate, age at survey, and sexual maturity together explained somewhat less than 20% and 10% of the variation of systolic and diastolic blood pressures, respectively. These screening data provide a baseline for a longitudinal study that will continue until 1982.