Standard blood pressure curves of schoolboys and schoolgirls in Akita prefecture.

Blood pressure of 251,742 schoolboys and schoolgirls aged 7 to 18 years was measured in the year 1970. Analyzing these data, the authors obtained the percentile values classified by age. The lowest hypertensive systolic blood pressures, which are represented by the 95th percentile, are 123, 126, 128, 128, 129, 134, 138, 144, 149, 152, 155, and 154 mmHg in boys from 7 to 18 years of age, respectively. The corresponding values are 123, 126, 128, 130, 134, 138, 139, 143, 144, 142, 142, 141 mmHg in girls of the same ages. Girls' systolic blood pressure is higher than that of boys between the ages of 10 and 13 years. After the 14th year of age, girls' systolic blood pressure does not increase any further, whereas boy's blood pressure continuously increases until 18 years. The present results differ in the following two points from the study in USA (1977): 1) The uniform rise of blood pressure with age is not observed. 2) Blood pressure, especially systolic pressure, is higher in girls than in boys between the ages of 10 and 13 years, although it is higher in boys thereafter until 18 years.