Measuring Children’s Blood Pressure Matters

n the 1970s, childhood, and particularly the part of child- hood before adolescence, was considered a low-cardio- vascular risk state. With the exception of specific conditions such as diabetes mellitus type 1, familial hypercholesterol- emia, end stage renal disease, and secondary hypertension, assessment of cardiovascular risk in children seemed unnec- essary. Childhood risk factor distributions were well below thresholds thought to be associated with risk for cardiovas- cular disease. Even today, it is not until adolescence that blood pressure classified as prehypertension by adult criteria is at the 90th percentile of the pediatric distribution.1 Article p 3171 In the Korean War, the observation that significant athero- sclerosis was present in young US soldiers dying in that conflict suggested that atherosclerosis had its origins in youth. This possibility has been dramatically confirmed by the Pathobiological Determinants in Youth (PDAY) study and the Bogalusa Heart Study where autopsy assessment of coronary and abdominal aortic atherosclerosis has been shown to relate directly to risk factors measured postmortem (PDAY) and those measured before accidental death (Bogalusa).2,3 The recognition that atherosclerosis is a chronic disease with possible origins early in life led several pioneering investigators in the United States and around the world, beginning in the 1970s, to measure cardiovascular risk factors in youth. In addition to determining the distribution of these risk factors at young ages, an important goal of these studies was to determine if risk in youth predicted risk later in life, a concept termed "tracking," meaning that those with higher or lower risk at initial measurement would likely retain that position relative to the rest of the cohort in the future. The presence of tracking would allow the identification of high- risk individuals at younger ages, so that disease prevention might begin during the earliest stages of atherosclerosis.4 In the current issue of Circulation, Chen and Wang, using meta-analytic techniques, provide an elegy of sorts for these many studies by combining them to retest the hypothesis that blood pressure measured early in life predicts blood pressure many years later.4 They demonstrate that, yes, blood pressure