Sleep among Brazilian adolescents before and after the COVID-19 pandemic: repeated cross-sectional and longitudinal analyses.

BACKGROUND

The COVID-19 pandemic significantly disrupted adolescents' routines, including their sleep patterns, due to school closures, social isolation, and increased screen time. As routines normalized post-pandemic, understanding whether these changes persisted or reverted to pre-pandemic levels is essential.

OBJECTIVE

To compare sleep variables between the periods before and after the COVID-19 pandemic in samples of Brazilian adolescents.

METHODS

A repeated cross-sectional study with a nested cohort targeting high-school students from Southern Brazil was used. Different sleep variables were obtained from wrist-worn accelerometers and validated questionnaires. Generalized linear mixed models with Gaussian distribution and identity link function were used to compare sleep variables between the survey years.

RESULTS

In 2019, 674 adolescents participated (51.8% female, mean age = 16.3, SD = 1.1), and in 2022, 625 participated (56.3% female, mean age = 16.5, SD = 1.2). In the longitudinal sample, 242 out of 333 eligible participants provided complete data in 2019, and 138 out of 286 agreed to participate in 2022. Cross-sectional data indicate significant differences for social jet lag (β: -0.28, p < 0.001) and self-reported sleep duration (β: -0.14, p = 0.03) between 2019 and 2022. Prospective data indicate significant changes for sleep regularity (β: -4.27, p < 0.001), daytime sleepiness (β: 1.05, p = 0.01), catch-up sleep (β: -0.35, p = 0.04) and self-reported sleep duration (β: -0.42, p < 0.001). However, effect sizes were all small.

CONCLUSION

Our findings suggest that adolescent sleep characteristics in Brazil post-COVID-19 are similar to pre-pandemic levels, indicating that the initial impact of the pandemic on sleep did not persist after routines normalized.