Heterogeneity in Blood Pressure and Lipid Trajectories throughout Childhood: Project HeartBeat!

Background: Previous studies have examined blood pressure (BP) and lipid changes through childhood and adolescence using population averages. We hypothesized that trajectories for these are heterogeneous, with sub-groups of the population showing different patterns in BP and lipid changes through childhood and adolescence. Methods: This study includes 678 children in Project HeartBeat!. Children were ages 8, 11, or 14 at baseline in 1991 and were examined every 4 mos for up to 4 yrs (mean number of exams, 8). At each exam, lifestyle, anthropometric and laboratory data was collected. Group-based modeling (PROC TRAJ) was used to identify trajectories in systolic BP (SBP), fifth phase diastolic BP (DBP5), total cholesterol (Chol), HDL Chol, LDL Chol and triglycerides as a function of age. The optimal number of race- and sex-adjusted trajectories was determined using the Bayesian Information Criterion and clinical expertise. Results: Among 678 children (49% female; 75% nonblack), 314 were enrolled at age 8, 197 at age 11, and 167 at age 14. Four distinct BP trajectories were identified (figure panels A-B). For SBP the low, low-intermediate, high-intermediate and high groups contained 16.4%, 36.3%, 34.5% and 12.7% of the sample, respectively; for DBP5, they contained 9.5%, 34.2%, 41.0%, and 15.3%. Three trajectories were identified for lipids (panels C-F). The low, intermediate, and high groups included 43.9%, 49.0% and 7.0% of the sample for total Chol, respectively. Corresponding figures were 33.4%, 49.3%, and 17.2% for HDL; 33.5%, 53.9%, and 12.7% for LDL; and 75.3%, 20.3%, and 4.5% for triglycerides, respectively. Girls were less likely (39% vs 61%) to be in the highest SBP groups as compared to the lowest. Blacks were more likely to be in the higher risk trajectories for DBP5 and HDL (p<0.01). Conclusion: Significant heterogeneity exists in BP and lipid trajectories throughout childhood. Finding predictors of the low and high trajectory classes may help target interventions to preserve low risk and manage high risk for future CVD. [ABSTRACT FROM AUTHOR]