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

Background: Public 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 the European Union (EU) adolescents over time have not been reported yet. This study aimed to identify SB of the EU adolescents (15-17 years) in four-time points (2002, 2005, 2013 and 2017) and to analyse the prevalence of SB according to the sex.

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 sexes 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 sexes (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, and for either girls or boys. Also, no significant differences in the prevalence of SB between girls and boys were found.

Conclusion: The SB prevalence in European adolescents is extremely high (76.8% in 2017) with no differences between girls and boys. No significant improvements have been seen between 2002 and 2017. Eurobarometer should increase the adolescents' sample to make possible benchmarking comparisons among the EU countries and extend the survey to the younger children population.