Moderating Role of Physical Fitness in the Association Between TV Time and Adiposity Parameters in Adolescents.

PURPOSE: To identify whether physical fitness (PF) components play a moderating role in the relationship between TV time and adiposity levels. DESIGN: Cross-sectional study. SETTING: Few studies have examined if different PF levels modify the association between TV time and adiposity in adolescents. Studies often focus on the isolated relationships between obesity and TV time, or obesity and PF levels. SUBJECTS: 1071 adolescents (617 girls), aged 12 to 17 years. MEASURES: Cardiorespiratory fitness (CRF), abdominal muscular endurance, and lower limb strength were evaluated using the protocols of the Projeto Esporte Brasil fitness testing battery. TV time was obtained using a self-reported questionnaire. Body mass index (BMI) and waist circumference (WC) were also assessed. Moderation analyses were conducted through multiple linear regression models with the following associations tested in different models: PF components, TV time, and interaction (PF component x TV time) with adiposity parameters (BMI and WC). RESULTS: A significant interaction term was found for CRF and TV time in the association with both WC (ß: -.005; 95% CI: -.009; -.001; P = .012) and BMI (ß: -.002; 95% CI: -.004; -.001; P = .009). CONCLUSION: CRF moderates the relationship between TV time and adiposity measures in this cross-sectional analysis. These data support strategies looking at increasing physical activity levels to improve CRF and avoid the development of excess abdominal obesity and excess weight.

Tracking of cardiometabolic risk in a Brazilian schoolchildren cohort: a 3-year longitudinal study.

BACKGROUND: Clustering of cardiometabolic risk factors is a sign of detrimental health. Tracking is a term used to describe a variable longitudinal stability across time. High tracking provides the chance to determine which cardiometabolic risk factors should be the target of early treatment and prevention efforts. The present study aims to analyze the tracking of cardiometabolic risk factors and clustered cardiometabolic risk score in children across a 3-year time span, and to verify the odds of staying at risk (measured by the clustered score) from baseline to follow-up. METHODS: Longitudinal study that included 354 (155 boys) children, aged 7-12 years at baseline. A clustered score was calculated by summing the systolic blood pressure, waist circumference, triglycerides, glucose, and the TC/HDL-C ratio Z-scores divided by five. A second clustered score was calculated including cardiorespiratory fitness (CRF). RESULTS: CRF and anthropometric parameters presented high tracking (r≥0.662), whereas the cardiometabolic parameters exhibited low-to-moderate tracking (0.100≤r≤0.571). The clustered scores' tracking was moderate (r≥0.508; r≥0.588 [CRF]). Participants in the higher risk groups at baseline presented 3.81 (95% CI: 2.40; 6.05) and 4.64 (95% CI: 2.85; 7.56), including CRF, times higher chance of remaining at risk three years later. Moreover, participants in the worst profile regarding CRF or anthropometrics at baseline presented at least 4.00 times higher chance of being at risk three years later. CONCLUSIONS: Participants with worst CRF and adiposity had an increased risk of presenting higher clustered risk after three years.