Effects of COVID-19 lockdown on children´s sleep quality, physical activity, screen time, and diet.

Introduction: Background: this study aimed to assess how the COVID-19 lockdown (March to June 2020) affected children's sleep quality, physical activity, screen time, and nutrition. Material and methods: the survey consisted of 479 children from the SENDO project, a pediatric cohort in Spain, aged 4-5 years. The BEAR questionnaire was used to evaluate sleep quality. Hierarchical models with two-level clustering were used to account for intra-cluster correlation between siblings, and the difference regression method was used to study the association between changes in screen consumption and physical activity and changes in sleep quality. Results: the results showed an increase in the consumption of homemade pastries and snacks. Sleep quality worsened significantly during confinement, with a mean score on the BEAR scale of 0.52 before, 1.43 during, and 1.07 after confinement. Although sleep quality improved significantly after the end of confinement, it remained worse than before. The average daily screen time increased from 1.13 hours before confinement to 2.65 hours during confinement. Physical activity decreased during confinement, with the mean number of hours per day decreasing from 1.27 to 0.79. Children who spent more time on screens during confinement had worse sleep quality, as indicated by their higher scores on the BEAR scale. We used the difference regression method to identify a statistically significant association between the increased screen time for leisure hours and the worsening of children's sleep quality during confinement. Conclusion: we observed a significant relationship between confinement and reduced sleep quality. Although the end of the lockdown led to a slight improvement, the average BEAR scale score remained higher post-confinement, suggesting that the consequences of the lockdown may persist over time.