Aerobic Fitness and Cardiometabolic Risk Factors in Elementary School Children

Background: Aerobic fitness, moderate-to-vigorous physical activity (MVPA), sedentary time (SED) and body mass index (BMI) are all associated with cardio-metabolic risk factors (CMRF) in children. However, few studies have examined the unique contribution of fitness to CMRF accounting for other covariates.

Purpose: To evaluate the association between fitness and CMRF in elementary school children when controlling for socio-demographic variables (age, gender, race, household income), MVPA, SED, and BMI percentile.

Methods: Aerobic fitness (Progressive Aerobic Cardiovascular Endurance Run [PACER] laps), MVPA/ SED over 4 days (ActiGraph GT3X+), height, weight, waist circumference (WC), blood pressure (SBP/DBP), and fasting blood samples were obtained from 2nd and 3rd grade students (N=206: 104 boys, 102 girls; age 7.6±0.6 yrs; BMI percentile: 63.5±28.6; minority: 16.3%). CMRF were compared between unfit (lowest 25% ~≤10 PACER laps) and fi t (upper 75%, >10 laps) children after controlling for socio-demographic variables (Model 1) and after additional control for BMI percentile, SED, MVPA (Model 2) using SAS PROC GLM.

Results: See table for adjusted means (standard error). Controlling for sociodemographic variables, fit children had higher HDL and lower insulin, triglycerides, Homeostatic Model Assessment-Insulin Resistance (HOMA-IR), and WC than unfit children (Model 1). After also controlling for MVPA, SED and BMI percentile (Model 2), the significant differences became non-significant with the exception of WC (p=0.04).

Conclusions: CMRF, with the exception of WC, do not differ significantly between fit and unfit children after controlling for socio-demographic variables, MVPA, SED and BMI percentile.

Funding: DK85317