Relationship between Objectively and Subjectively Measured Physical Activity in Adolescents during and after COVID-19 Restrictions

COVID-19 pandemic-related weight gain in the pediatric population declined after restrictions ended, except among obese patients

Introduction

Childhood obesity has become an important topic, not only of increasing relevance during the COVID-19 pandemic but specifically enhanced by it. Restrictions implemented to mitigate further outbreaks led to major constraints on daily physical activity, leading to a severe increase in body weight among children. This study highlights changes in BMI and weight development in children during and (in particular) after the COVID-19 restrictions in Austria, focusing on various socioeconomic factors.

Methods

Weight development throughout the pandemic and socioeconomic factors were evaluated by anonymous cross-sectional surveys filled out by parents at a pediatric practice.

Results

This study included 388 children. The rate of obesity increased by 88.5%, from 6.4 to 12.1%, throughout the pandemic, reaching a maximum of 15.2% during the restrictions. Overall, age-adapted BMI z-scores increased significantly by 0.22 during the restrictions and remained increased by 0.19 compared to pre-pandemic levels. With the exception of obese children, all children in the study population experienced significant weight loss after the restrictions were lifted. Obese children continued to gain weight without any sign of the onset of normalization. Socioeconomic factors, such as participation in regular activity in the form of organized sport or the availability of an outdoor area, were associated with relevant differences before the pandemic but had no protective effect against intra-pandemic weight gain. A higher level of parental education was the only factor associated with less weight gain in children during the early phase of the pandemic.

Discussion

Austrian COVID-19 restrictions have had concerning effects on pediatric BMI, with very little effect of socioeconomic background. After restrictions were loosened, measurable weight loss occurred, but the significant increase in children's BMI percentiles persisted. No weight loss was observed among children who were obese prior to the pandemic. There is a need for broad projects tackling childhood obesity, as obese children are the most vulnerable group with the strongest and most severe long-term effects.

Discrepancies Between Self-reported and Objectively Measured Smartphone Screen Time: Before and During Lockdown

Screen time shows higher health risks compared to other types of sedentary behaviors. A lockdown may simultaneously increase screen time, reduce physical activity (PA), and change time perception. Our goal was to compare self-reported against objectively measured smartphone screen time (SST) in a sample of active and inactive Portuguese adults before and during a social lockdown. This study was a cross-sectional analysis with 211 Portuguese adults (57.8% males), aged 25.2 ± 8.5 years, from two cohorts, one before the social lockdown and the other during the lockdown. SST was self-reported (SR-SST) and objectively measured using a smartphone (OM-SST). PA was self-reported. Linear regressions were performed to determine the association between SR-SST and OM-SST. A Bland and Altman analysis was used to assess agreement. Independent T-tests were performed for comparisons between cohorts and paired sample T-tests for comparisons within each cohort. The cohort assessed during the lockdown showed a higher SST than the cohort assessed before the lockdown (OM-SST; p < 0.001 and SR-SST; p = 0.009). Before the lockdown, there was no difference between SR-SST and OM-SST (p = 0.100). However, during the social lockdown, although the agreement between SR-SST and OM-SST was good (ICC = 0.72), participants systematically underestimated their SST by ~ 71 min/day (p < 0.001), and this underestimation was higher in inactive participants (~ 85 min/day) than in active individuals (~ 49 min/day). The general population needs to be aware of the benefits of limiting screen time, especially during periods of societal modifications, such as a generalized lockdown. There was a tendency to underestimate SST, meaning a lack of awareness of the actual time spent in this potentially deleterious behavior. This underestimation was more pronounced during the lockdown period and for the inactive participants, thus posing a greater health risk. The findings from this investigation entail relevant information for policy makers to delineate strategies for reducing population screen time from a preventive health perspective.

Change in BMI and Fitness among Primary School Children in Austria: A 24-Month Follow-Up Study of 303 Children Measured before and during the Ongoing COVID-19 Pandemic

The ongoing COVID-19 pandemic not only impacted the health of school children directly through SARS-CoV-2 infections, but the associated closures of schools and sports facilities also resulted in long-term negative side effects. The aim of this study was to investigate the effects of COVID-19-related mitigation measures on the health and fitness status of primary school children in Austria. A total of 303 primary school children participated in the longitudinal study. Data on height, weight, and fitness were collected before the COVID-19 pandemic (September 2019) and at one-year intervals (September 2020 and September 2021) during the course of the pandemic. In the first year, from September 2019 to September 2020, there were alarming increases in body mass index (BMI) standard deviation scores (SDSs) (from 0.32 to 0.49) and dramatic decreases in both cardiorespiratory endurance (CRE) (from 0.49 to −0.43) and action speed (from −0.31 to −0.64). In the second year (September 2020 to September 2021), the BMI scores stabilized, and improvements in CRE were observed, especially in the subgroup of children who were members of sports clubs. In the future, more initiatives and projects, in addition to sports club activities, should be started and expanded, particularly in schools, to specifically counteract the observed health damage and, thus, have a positive effect on the development of all children, especially those without sports club membership.