Longitudinal relationship between screen time, cardiorespiratory fitness, and waist circumference of children and adolescents: a 3-year cohort study

PURPOSE: The aim of this study was to examine the interaction between screen time and cardiorespiratory fitness (CRF) in their longitudinal association with waist circumference (WC) during a follow-up of 3 years from childhood to adolescence. METHODS: Observational 3-year longitudinal study with 401 students (224 females), seven to 15 years of age at baseline. The CRF was evaluated by estimating peak oxygen uptake (VO(2peak)) from an indirect field-based test and body mass index. Screen time was assessed using self-reported questionnaires. Moderation analyses were tested using a multiple linear regression model with adjustments for sex, age, puberty stage, and ethnicity. RESULTS: A statistically significant interaction term was observed (B = -0.0003; 95% CI: -0.007; -0.0001). Since screen time was contextualized as the independent variable, the results show that relationship between screen time and WC varies across different CRF levels. CONCLUSION: The findings suggest that higher CRF can attenuate the harmful association that increased sedentary behavior might have on abdominal adiposity.