Fat distribution, physical activity and cardiovascular risk among adolescent girls

It is not clear whether changes in waist circumference (WC), sums of skinfold thickness (SSF), or levels of physical activity (PA) during adolescence are associated with cardiovascular risk factors, or if associations are independent or interactive.

In a US cohort of adolescent girls (n = 617-904) girls, examined at ages 12 and 14, WC, SSF, PA, systolic and diastolic blood pressure (SBP & DBP) were assessed. Fasting blood samples were used to determine concentrations of triglycerides (TG), cholesterol (TC), high and low density lipoproteins (HDL-C and LDL-C), and apolipoprotein A1 and B (Apo-A1 and Apo-B). After adjustment for change in SSF and PA, increases in WC were associated with change in TG (z = 1.73, 95% CI = 0.77, 2.69), TC (z = 0.45, 95% CI = 0.01, 0.90), HDL-C (z = -0.18, 95% CI = -0.37, -0.01), LDL-C (z = 0.41, 95% CI = 0.03, 0.80), Apo-A1 (z = -0.52, 95% CI = -1.02, -0.02), Apo-B (z = 0.60, 95% CI = 0.24, 0.97) and SBP levels (z = 0.31, 95% CI = 0.15, 0.47). Associations between changes in SSF and PA with cardiovascular risk were eliminated after adjustment for WC, and all interactions between WC, SSF and PA were non-significant at conventional levels.

Changes in WC were independently associated with the development of cardiovascular risk factors, whereas changes in SSF and PA were not. Clinicians should consider the routine screening of WC to monitor cardiovascular health in adolescent girls.