Objective: To investigate the familial aggregation of metabolic risk factors (RF) according to blood pressure (BP) percentile of children and adolescents.
Design and methods: Normal BP was established in 3906 children and adolescents in 1987. From this population two groups of target individuals were separated: group A (n = 327) with systolic and/or diastolic BP percentile > 95 and group B (n = 327) with systolic and diastolic BP percentile < or = 50. Ten years later, familial aggregation of metabolic RF was evaluated using clinical and laboratorial data from 785 individuals, divided into two groups: group 1 with 135 target individuals (BP percentile > 95), 181 parents, 100 siblings and 16 grandparents; and group 2: 106 target individuals (BP percentile < or = 50), 145 parents, 84 siblings and 18 grandparents.
Results: (1) The longitudinal study 10 years later (tracking effect) showed that 34.8% of target individuals of group 1 and 90.5% of group 2 remained at the same BP percentile. (2) Comparing the two groups of target individuals, group 1 had higher weight and body mass index (BMI), systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) (P < 0.001) and lower HDL (P < 0.003). (3) Comparing target individuals' and their relatives' measurements together, group 1 had higher BMI, HR, SBP, DBP (P < 0.03) and lower HDL (P < 0.001). (4) SBP and DBP showed significant correlation with all metabolic variables even when BMI was controlled in a multiple regression analysis (P < 0.04).
Conclusion: BP level in children and adolescents was a good marker for familial aggregation of metabolic RF, suggesting an interaction of genetic and environmental factors. Primary intervention should be carried out in early stages of life.