Tracking of blood pressure, height, weight and left ventricular muscle volume in children--the Shimane Heart Study.

Two cohorts of Japanese children were studied longitudinally at 3-year intervals, at ages 6 and 9 years in cohort 1 and 9 and 12 years in cohort 2. There were 252 children in cohort 1 and 235 in cohort 2. The examinations performed were blood pressure, height, weight, skin fold thickness, upper arm length and circumference, ECG, VCG, M-mode echocardiography, serum cholesterol, hemoglobin and urinalysis. The subjects were divided into 5 quintile groups by their systolic blood pressure (SBP) percentiles calculated at each examination. SBP was tracked in each cohort throughout the follow-up period. Percentages remained in the highest SBP quintile group at both examinations were 43.5% (boys) and 59.1% (girls) in cohort 1, and 25.0% (boys) and 56.5% (girls) in cohort 2. The tracking of SBP was defined by body mass (height and weight) in most children. In some children, however, it was not defined by body mass tracking. Left ventricular muscle volume and its index were large in boys in the highest SBP tracking group. This indicates that the cardiac muscle is hypertrophied already, before the development of hypertension.