Fatness, Fitness and Cardiovascular Disease Risks in Adolescents in the Cardiovascular Health Intervention Program (CHIP)

Abstract

Pediatric obesity is of great health concern because of its profound adverse impact on youth physical and mental health, and its strong linkage with risks of obesity and cardiovascular diseases (CVD) later in life. Cardiorespiratory fitness, on the contrary, confers protection against various cardio-metabolic risks, associated morbidities and mortality. It is unclear how fatness and fitness together determine health risk profiles in adolescents. PURPOSE: To examine the differences in cardio-metabolic risk factor levels and in prevalence of risk factor clustering across four fatness-fitness groups among 6th grade students. METHODS: 2950 students (51% female, 95% Caucasian, 10 to 13 years) from 17 schools were screened. They were categorized into four groups, i.e. lean-fit, lean-unfit, fat-fit and fat-unfit using national norms. Risk factor measures included resting blood pressure, fasting glucose, triglycerides, total and high-density lipoprotein cholesterol, and waist-height-ratio. Group differences in risk factor levels were tested by ANOVA, and prevalence of risk factors clustering by c2 test. RESULTS: Higher prevalence of overweight was observed in unfit group than in fit group (unfit vs. fit, 87 vs. 26% in girls and 90 vs. 28% in boys, p<0.0001, c2 test). The main effect of fitness-fatness status was significant for almost all risk factors (p≤0.0001), except for LDL and total cholesterol in girls. Risk factor levels progressed from low to high (high to low for HDL) across four groups as lean-fit → lean-unfit → fat-fit → fat-unfit, and the differences between fat-fit and lean-fit groups were much smaller than between fat-unfit and lean-fit groups. Cardio-metabolic risk factor clustering (88 and105 cases in girls and boys) was significantly associated with fatness-fitness status (p<0.0001, c2 test,): in girls, 72% of the cases were present in fat-unfit group and 24% fat-fit group; in boys, 78% in fat-unfit group and15% fat-fit group. CONCLUSION: Fatness and fitness are both important in determining cardio-metabolic risks among adolescents. Interventions with a potential to decrease fatness and increase fitness, such as exercise training, may be beneficial for risk factor reduction among pediatric overweight/obese population. Supported by grant NINDS - 1R01NS040606.