Impact of the<scp>COVID</scp>‐19 pandemic on elementary schoolers' physical activity, sleep, screen time and diet: A quasi‐experimental interrupted time series study

<jats:title>Summary</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>COVID‐19 school closures pose a threat to children's wellbeing, but no COVID‐19‐related studies have assessed children's behaviours over multiple years .</jats:p></jats:sec><jats:sec><jats:title>Objective</jats:title><jats:p>To examine children's obesogenic behaviours during spring and summer of the COVID‐19 pandemic compared to previous data collected from the same children during the same calendar period in the 2 years prior.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Physical activity and sleep data were collected via Fitbit Charge‐2 in 231 children (7–12 years) over 6 weeks during spring and summer over 3 years. Parents reported their child's screen time and dietary intake via a survey on 2–3 random days/week.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Children's behaviours worsened at a greater rate following the pandemic onset compared to pre‐pandemic trends. During pandemic spring, sedentary behaviour increased (+79 min; 95% CI = 60.6, 97.1) and MVPA decreased (−10 min, 95% CI = −18.2, −1.1) compared to change in previous springs (2018–2019). Sleep timing shifted later (+124 min; 95% CI = 112.9, 135.5). Screen time (+97 min, 95% CI = 79.0, 115.4) and dietary intake increased (healthy: +0.3 foods, 95% CI = 0.2, 0.5; unhealthy: +1.2 foods, 95% CI = 1.0, 1.5). Similar patterns were observed during summer.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Compared to pre‐pandemic measures, children's PA, sedentary behaviour, sleep, screen time, and diet were adversely altered during the COVID‐19 pandemic. This may ultimately exacerbate childhood obesity.</jats:p></jats:sec>