Abstract P267: Cardiorespiratory Fitness Does not Attenuate the Association Between Adiposity and Blood Lipids in Children and Adolescents: Project HeartBeat! (1991-1995)

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Background: Higher levels of adiposity are associated with unfavorable blood lipid levels in pediatric populations. However, little is known about the extent to which cardiorespiratory fitness attenuates this association. Methods: Participants ages 8-16 years (n=256) with valid measures of blood lipids, cardiorespiratory fitness (CRF) and adiposity were examined from Project Heartbeat!, a longitudinal study of cardiovascular risk factors among children and adolescents. CRF was assessed by maximum oxygen uptake: VO 2max (mL/kg/min) measured during treadmill testing and adiposity was assessed by percent body fat (PBF) estimated using sex-specific formulas incorporating bioelectric impedance and six-site skinfold measures. Fasting blood lipids included total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C). Linear regression was used to quantify cross-sectional associations between CRF and adiposity with blood lipids by sex and pubertal status (Tanner stage 1 vs. 2-5). Results: When examined individually, higher PBF and lower VO 2max were associated with more favorable levels of blood lipids in pre-pubertal boys, however, the associations were not consistent across all sex/puberty groups (Table 1). In multivariate models where both VO 2max and PBF were included, PBF remained significant for all blood lipids in pre-pubertal boys but only with TC and LDL-C in pre-pubertal girls. Among pubertal participants, only TG remained significantly associated with PBF when similarly accounting for VO 2max . Conclusions: Prior to the onset of puberty, higher adiposity is independently associated with more favorable levels of TG and HDL-C in boys and TC and LDL-C in girls even after accounting for CRF. During puberty, the majority of these associations are greatly attenuated, which further highlights the complexities associated with examining correlates of blood lipids in developing children.