Combined effects of child and adult elevated blood pressure on subclinical atherosclerosis: the International Childhood Cardiovascular Cohort Consortium

Abstract

Background: Elevated blood pressure (BP) levels in childhood have been associated with subsequent atherosclerosis. However, it is uncertain whether this risk is attenuated in individuals who acquire normal BP by adulthood. The present study examined the effect of child and adult BP levels on carotid artery intima-media thickness (IMT) in adulthood.

Methods and results: The cohort consisted of 4210 participants from 4 prospective studies (mean follow-up, 23 years). Childhood elevated BP was defined according to the tables from the National High Blood Pressure Education Program. In adulthood, BP was classified as elevated for individuals with systolic BP ≥120 mm Hg, diastolic BP ≥80 mm Hg or with self-reported use of antihypertensive medications. Carotid artery IMT was measured in the left common carotid artery. High IMT was defined as an IMT ≥90th percentile according to age-, sex-, race-, and cohort-specific levels. Individuals with persistently elevated BP and individuals with normal childhood BP, but elevated adult BP had increased risk of high carotid artery IMT (relative risk [95% confidence interval]) 1.82[1.47-2.38] and 1.57[1.22-2.02], respectively) in comparison with individuals with normal child and adult BP. In contrast, individuals with elevated BP as children but not as adults did not have significantly increased risk (1.24[0.92-1.67]). In addition, these individuals had a lower risk of increased carotid artery IMT (0.66[0.50-0.88]) in compared with those with persistently elevated BP. The results were consistent when controlling for age, sex, and adiposity and when different BP definitions were applied.

Conclusions: Individuals with persistently elevated BP from childhood to adulthood had increased risk of carotid atherosclerosis. This risk was reduced if elevated BP during childhood resolved by adulthood.

Keywords: atherosclerosis; blood pressure; epidemiology; hypertension; risk factors.

Figure 1

Forest plots showing relative risk of high carotid intima media thickness (cIMT) in four cohorts. Data were analyzed from four studies — the Muscatine Study, the Bogalusa Heart Study, the Cardiovascular Risk in Young Finns Study, and the Childhood Determinants of Adult Health (CDAH) Study. In each individual study cohort and in a meta-analysis of all four cohorts, the risk of high cIMT (≥90^th percentile for age-, sex-, race-, study-year–, and cohort-specific values) is shown. Child blood pressure (BP) was classified as elevated if systolic or diastolic BP were ≥90^thpercentile using the NHBPEP tables for age, sex, and height. Adult BP was classified as elevated if Systolic BP≥120mmHg or Diastolic BP≥80mmHg. In addition, adult BP status was considered elevated among those self-reporting use of antihypertensive medications. Participants who had a normal blood pressure (BP) in childhood and had normal BP as adults (Control) were compared with participants who had elevated BP in childhood but not as adults (Resolution), participants with a normal BP in childhood who had elevated BP as adults (Incident), and participants who had elevated BP in childhood and as adults (Persistent). The size of each box is proportional to the weight of the cohort in the meta-analysis. The diamonds represent the relative risks estimated from the meta-analysis, with the lateral points indicating the 95% confidence intervals. The P values for heterogeneity among groups were 0.34 for the comparison of Resolution with Control, 0.27 for the comparison of Incident with Control, and 0.15 for the comparison of Persistent with Control, suggesting that there was no dissimilarity among cohorts