Blood pressure in childhood and adolescence. Results from an international collaborative study on juvenile hypertension.

A total of 17,130 children of both sexes born in 1964 and living in Hungary, USSR, GDR and Cuba were examined in 1977. The children were grouped in upper (U) and lower (L) blood pressure groups and 3,640 children were re-examined in 1978-1981. The parents' age, smoking habits, marital status, the children's order of birth, number of siblings, and proportion of twins did not differ between U and L. The prevalence of hypertension and diabetes in the medical history of the children, and the prevalence of hypertension and stroke and diabetes in the medical history of the parents were significantly higher in U than in L. Signs of left ventricular hypertrophy and systolic murmurs, the magnitude of R and S waves in the ECG, and mean values of cardiothoracic and heart volume indices were higher in U than in L. Children in U were sexually more developed, taller, more obese (greater Quetelet's index and skinfold thickness) and less active physically. Average values of blood sugar and serum uric acid were also higher in U than in L. No difference was found between the two groups in the proportion of smokers and in mean cholesterol values. These differences between U and L were strengthened in comparison of children who showed repeatedly low (below the 30th percentile) or high (at or above the 70th, 90th and 95th percentile) readings in the SBP and DBP distribution curves. Since we did not find important differences when we related various factors to blood pressure taken on one or two separate occasions we emphasize the importance of casual blood pressure measurement in childhood.