BACKGROUND: This study examined a) trends in overweight/obesity, moderate-to-vigorous physical activity (MVPA), and screen time (ST) among Czech adolescents over a 12-year study period (2002-2014) in relation to family affluence (FA) and b) correlates of adolescent overweight/obesity from different FA categories. METHODS: A nationally representative sample of 18,250 adolescents (51.4% girls) aged 10.5-16.5 years was drawn from the Czech Health Behaviour in School-aged Children questionnaire-based surveys in 2002, 2006, 2010, and 2014. Using the FA scale, the socioeconomic status (SES) of the respondents' families was assessed. SES-stratified trends in the prevalence of overweight/obesity meeting the MVPA (≥60 min/day), and ST (≤2 h/day) recommendations were assessed using logistic regression. RESULTS: A trend-related significant increase (p < 0.05) in the prevalence of overweight/obesity was observed in low-/medium-FA boys and medium-/high-FA girls. Unlike in high-FA adolescents, a significant decrease was revealed in the rates of meeting the MVPA recommendation in low-FA boys (28.9%2002 → 23.3%2014, OR = 0.75, 95% CI = 0.59-0.95, p < 0.05) and girls (22.3%2002 → 17.3%2014, OR = 0.73, 95% CI = 0.57-0.92, p < 0.01). A significant (p < 0.001) trend-related increase in excessive ST was evident in adolescents regardless of gender and FA category. Generally, girls and older adolescents had lower odds of overweight/obesity than boys and 11-year-old adolescents. While in the high-FA category of adolescents, achieving 60 min of MVPA daily and the absence of excessive ST on weekdays significantly (p < 0.01) reduced their odds of being overweight/obese, in low-FA adolescents this was not the case. CONCLUSIONS: High rates of overweight/obesity and a poor level of daily MVPA among low-FA children provide disturbing evidence highlighting the necessity of public health efforts to implement obesity reduction interventions for this disadvantaged population.

Department of Computer Science Faculty of Science Palacký University Olomouc Tr 17 Listopadu 77146 Olomouc Czech Republic

Department of Recreation and Leisure Studies Faculty of Physical Culture Palacký University Olomouc Tr Miru 117 77111 Olomouc Czech Republic

Department of Social Sciences in Kinanthropology Faculty of Physical Culture Palacký University Olomouc Tr Miru 117 77111 Olomouc Czech Republic

Institute of Active Lifestyle Faculty of Physical Culture Palacký University Olomouc Tr Miru 117 77111 Olomouc Czech Republic

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