Tracking of physical and physiological risk variables among ethnic subgroups from third to eighth grade: the Child and Adolescent Trial for Cardiovascular Health cohort study

Abstract

Background: The Child and Adolescent Trial for Cardiovascular Health (CATCH), a multisite field trial, tested the effectiveness of multiple interventions for cardiovascular disease risk behaviors in children in third through fifth grades. This paper reports the tracking of physiologic variables through eighth grade.

Methods: The cohort began with 5,106 third grade students from diverse ethnic backgrounds: 69% Caucasian, 14% Hispanic, 13% African American, and 4% other. Seventy-two percent of students were remeasured. Measures described are serum lipids, blood pressure, and body anthropometrics. Tracking was examined across three time points (third, fifth, and eighth grades) with a scaled Kendall concordance coefficient and percentage retention within quintiles across time.

Results: For the overall sample, tacking was strongest for body mass index (BMI) (Kendall coefficient = 0.86) and weight (0.86), followed by skinfold thicknesses (0.72-0.78), serum lipids (0.67-0.72), and blood pressure (0.45-0.51). For BMI, 96% of students stayed within +/-1 quintile from third to fifth grades; 90% stayed within this range from third to eighth grades.

Conclusions: There were small but noticeable gender and ethnic differences: tracking was stronger among boys and African American students. These results demonstrate that the children's relative level of cardiovascular risk remained stable over a 6-year period.