No changes in adolescent's sedentary behaviour across Europe between 2002 and 2017

Background: Health organizations have been alerted to the high levels of sedentary behaviour (SB) among adolescents as well as to the health and social consequences of excess sedentary time. However, SB changes of European Union (EU) adolescents over time are yet to be reported. This study aimed to identify SB changes the EU adolescents (15-17 years) between 2002 and 2017, and to analyse the prevalence of SB according to the gender. Methods: : SB of 2542 adolescents (1335 boys and 1207 girls) as a whole sample and country-by-country was analysed in 2002, 2005, 2013, and 2017 using the Sport and Physical Activity EU Special Eurobarometers' data. SB was measured using the sitting time question from the short version of the International Physical Activity Questionnaire (IPAQ), such that 4h30min of daily sitting time was the delineating point to determine excess SB behaviour (≥4h30min of sitting time) or not (≤4h30min of sitting time). A χ2 test was used to compare the prevalence of SB between survey years. Furthermore, SB prevalence between genders was analysed using a Z-Score test for two population proportions. Results: : The prevalence of SB among EU adolescents across each of the four survey years ranged from 74.2% and 76.8%, rates that are considered high. High levels of SB were also displayed by both genders (girls: 76.8% to 81.2%; boys: 71.7% to 76.7%). No significant differences in the prevalence of SB among years (p>0.05) were found for the whole sample, girls, or boys. Also, no significant differences in the prevalence of SB between girls and boys were found. Conclusion: The SB prevalence in adolescents is extremely high (76.8% in 2017) but remained steady from 2002-2017, and European girls and boys reported similar prevalence of SB across the same time frame.