Evolution of Sleep Duration and Screen Time Between 2018 and 2022 Among Canadian Adolescents: Evidence of Drifts Accompanying the COVID-19 Pandemic.

PURPOSE: We quantified the joint evolution of sleep duration and screen time between 2018 and 2022 in a large sample of adolescents from Quebec, Canada, to ascertain changes that occurred during the COVID-19 pandemic. METHODS: A natural experiment design was used to compare variations from year to year and in association with the pandemic outbreak. Using structural equation modeling on data collected between 2018 and 2022 among adolescents attending 63 high schools, we analyzed the joint evolution of sleep duration and screen time while adjusting for previous year values, concurrent flourishing score, sex, age, and family level of material deprivation. RESULTS: A total of 28,307 adolescents, aged on average 14.9 years, were included in the analyses. Between 2019 and 2022, sleep duration increased by 9.6 (5.7, 13.5) minutes and screen time by 129.2 (120.5, 138.0) minutes on average. In 2022, the adolescents spent almost equal amounts of time sleeping and using screens. Lower flourishing scores were associated with shorter sleep duration and lengthier screen time. Girls' screen time became similar to boys' over time. DISCUSSION: Adolescents now spend almost equal amounts of time sleeping and using screens, a situation that calls for urgent public health actions. These findings highlight the importance of tracking changes in adolescents' behaviours over time, to design and implement interventions adapted to the changing health needs of different groups.

Estimating consumer preferences for different beverages using the BLP approach.

The overconsumption of sugar is a significant problem in many jurisdictions, and one possible method to remedy this problem is the taxation of sugar-sweetened beverages (SSBs). To be able to implement an optimal tax, it is important to know the preferences and price sensitivity of consumers. This article therefore estimates the price elasticity of demand for different beverages in Quebec, using the Berry, Levinsohn and Pakes (BLP) random parameter logistic demand model, combined with Nielsen data from 2010 to 2016 and the 2016 Canadian Census. The results suggest that the average consumer prefers high-calorie beverages containing fruits and vegetables, and the estimated price elasticities are between -4.40 (energy drinks) and -1.59 (regular soft drinks). As a result, consumers of energy drinks appear to reduce their consumption the most in the face of rising prices, whereas consumers of soft drinks will decrease their consumption the least. However, at a general level, the implementation of a tax on SSBs in Quebec should generate a significant reduction in consumption.