Prevalence of social jetlag and associated factors in Brazilian adolescents: Results from a country-wide cross-sectional study.

Objectives: Social jetlag is a disturbance in the circadian rhythm caused by a desynchronization between an individual's biological rhythm and social commitments and responsibilities. It leads to sleep debt during the week and compensation on weekends. Social jetlag is associated with an increased risk of chronic diseases and cognitive dysfunction in adolescents. This study aims to assess the prevalence of social jetlag and associated factors in Brazilian adolescents.

Methods: Adolescents of both sexes, aged between 12 and 17years, participating in the Study of Cardiovascular Risks in Adolescents (ERICA), were included. The sleep duration on a typical weekday and weekend day was collected through a self-reported questionnaire. The occurrence of social jetlag was defined as the difference between the midpoint of sleep on weekends and weekdays, with differences equal to or higher than 1hour considered as an indicator of positive social jetlag. Factors associated with the prevalence of social jetlag were investigated using Poisson regression models.

Results: The sample included a total of 64,029 adolescents. Social jetlag affects more than 80% of Brazilian adolescents, with higher prevalence among girls in the age group of 16-17years, with white skin color, attending private schools, and those having morning classes. Additionally, unhealthy risk behaviors such as skipping breakfast, alcohol consumption, and increased screen time are associated with a higher prevalence of social jetlag.

Conclusion: The prevalence of social jetlag was high in Brazilian adolescents, and, among its associated factors, studying in the morning shift and engaging in unhealthy risk behaviors stand out.