Background: Many studies have examined the blood pressure tracking among children and adolescents, but the results have been mixed. This study examined blood pressure tracking in 304 Korean school children following them for 5 years from age 6 to 11.
Methods: In addition to the examination of relative ranking, in percentile groups, of blood pressure and time-lag correlation analysis, we used the McMahan's tracking index, tau (tau), which indicates the proportion of variation attributable to tracking apart from the natural growth (increase) component.
Results: There was strong evidence for tracking during the pre-teen years, particularly when it was analysed using McMahan's tracking index. Tau for systolic blood pressure was 0.877 (+/- 0.028) in males and 0.792 (+/- 0.044) in females. For diastolic blood pressure tau was found to be 0.924 (+/- 0.070) in males and 0.762 (+/- 0.075) in females.
Conclusions: This study supported the existence of blood pressure tracking in children, but data were insufficient to examine the effect of puberty on tracking. The need for further research is emphasized with the aim of incorporating biological and behavioural factors and targeting preventive intervention.