Introduction

Health behaviors play a crucial role in the physical and mental health of children and adolescents1,2. Prolonged measures taken to curb the spread of the COVID-19 pandemic, such as remote schooling, limitation of in-person contacts and restricted access to recreational facilities, disrupted health behaviors of young people, at least temporarily3.This is supported by meta-analyses reporting a 52% increase in screen time4, a 20% decrease in physical activity5, and an increased sleep duration paired with decreased sleep quality6 in children and adolescents, two years into the pandemic. The magnitude of these changes appeared smaller in countries with milder restrictions7. For instance, in Switzerland, outdoor exercise and walking were never prohibited, unlike in neighboring countries such as Italy and France, where only essential trips were allowed during the initial lockdown8. Differences in opportunities for physical and non-screen-based activities persisted in later stages of the pandemic, as access to recreational facilities required proof of vaccination, recovery, or a negative test from 16 years old in Switzerland9compared to 12 years old in France and Italy10,11.

Socially disadvantaged young individuals may have been particularly vulnerable to a deterioration in lifestyle. Indeed, unfavorable socio-economic circumstances are associated with lower access to green spaces12, which proximity was shown to be key in fostering outdoor recreational activities and limiting screen time during the pandemic13. Furthermore, socio-economically disadvantaged families were at heightened risk of financial and parenting strain14possibly reducing the parental availability to encourage healthy behaviors in their children.

Only a few population-based studies empirically investigated whether the social patterning of children’s and adolescents’ health behaviors changed with the pandemic15,16,17. A Chilean study found that among young children, higher parental education was associated with a greater increase in screen time and a greater decrease in physical activity behaviors, while a higher income was protective against a decline in sleep quality15. On the contrary, in Hong-Kong, children and adolescents with high family affluence more frequently reported an increase in exercise time than their less advantaged peers16. These studies showed inconsistent findings, were conducted early in the pandemic and could not assess lasting changes in behaviors and in their social distribution. Furthermore, government response to the pandemic varied widely and there is little evidence from countries with relatively light restrictions, such as Switzerland18.

We thus aimed to (1) estimate children’s and adolescents’ (referred to as children hereafter) adherence to health behavior recommendations two years into the COVID-19 pandemic, (2) investigate demographic and socio-economic correlates of adherence to those recommendations, and (3) examine correlates of perceived behavior changes because of the pandemic, in Geneva, Switzerland.

Results

Overall, 2104 children (mean age: 10.2 years; 49.3% girls) were included (Table 1). When weighted by the Geneva population’s age and sex distribution, approximately one in three children did not meet screen time or physical activity recommendations (32.0% and 31.8%, respectively), while 21.8% did not sleep sufficiently, with important variations according to age (Table 1). On average, children spent 4 h 51 min per week in green spaces.

Table 1 Time spent engaging in health behaviors and non-adherence to corresponding recommendations according to socio-demographic characteristics among children and adolescents, in Geneva, Switzerland, 2022.
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The older the children, the less likely to adhere to recommendations, whichever the behavior (Fig. 1). Girls, especially older ones, displayed lower adherence to physical activity and sleep guidelines than boys, and spent less time in green spaces (Supplementary Table 1). Overall, children of parents with a low educational level were less likely to meet recommendations than those of highly educated parents, although this pattern varied depending on child age and behavior type. Educational differences seemed to decrease with age for recreational screen time and sleep duration, while they reversed for physical activity, and remained constantly non-significant for time spent in green spaces (Fig. 1). Results were similar when examining parents’ birth country and household financial situation (Supplementary Fig. 1).

Fig. 1
Fig. 1
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Predicted proportion of children not meeting health behavior recommendations according to age and parents’ highest education in Geneva, Switzerland, 2022. Results are from generalized estimating equations adjusted for sex (and physical limitations for physical activity), shaded areas correspond to the 95% confidence interval. Analyses performed on complete cases.

Two years into the pandemic, parents estimated that physical activity, green spaces time and sleep quality had remained unchanged for most children (72.9%, 72.2% and 93.1%, respectively). A smaller proportion of children experienced either an increase or decrease in physical activity and green spaces time, or a worsening in sleep quality (Table 2). Changes in recreational screen time were the most prevalent, with an increase reported for about half of children (51.9%). When evaluating correlates of pandemic-related changes, older age was associated with an increased likelihood of a worsening of all four health behaviors (Table 2). Additionally, the odds of decreased physical activity were 1.43 (95% CI: 1.03-2.00) and 1.53 (95% CI: 1.16–2.03) times higher among children of parents with a lower educational level or born outside of Switzerland, respectively. Similarly, the odds of reduced time spent in green spaces were 1.78 (95% CI: 1.23–2.57) and 1.59 (95% CI 1.17–2.17), respectively, for these groups. Compared with a very good household financial situation, average-to-poor circumstances were associated with an increase in recreational screen time, as well as with both an increase/improvement or decrease/worsening in physical activity, green spaces time and sleep quality (Table 2).

Table 2 Association between socio-demographic characteristics and changes in health behaviors due to the COVID-19 pandemic among children and adolescents in Geneva, Switzerland, 2022.
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Discussion

A meaningful proportion of children did not meet health behavior recommendations in 2022, particularly among girls and adolescents. Socio-economic patterns varied depending on age and behavior type. The COVID-19 pandemic triggered both an improvement and worsening of behaviors, although most children in our sample did not experience pandemic-related changes. Older children were at increased risk of an overall worsening of health behaviors due to the pandemic, while children from disadvantaged households were more likely to experience any changes, whether positive or negative.

The prevalence of children meeting screen and sleep recommendations in 2022 was comparable to Swiss estimates of fall 2020, one year into the pandemic19. Indeed, schools were open in both periods and children’s routine was probably similar. On the other hand, our estimates of adherence to physical activity guidelines were higher than reported in Switzerland in fall 202019, possibly because organized physical activities were still limited in 2020, as opposed to 2022 when the current study took place. This implies that lifting pandemic-related restrictions had a positive effect on children’s physical activity. Conversely, non-adherence to recommendations for screen time and sleep duration persisted at the high levels observed during the first year of the pandemic and might require close monitoring.

As commonly observed, correlates of not meeting recommendations included older age for all of the behaviors under study20,21,22and female sex for physical activity20. However, adolescent girls’ lower adherence to sleep guidelines was surprising in our study22. The differences in socio-economic patterns according to age and behavior type reflected previous findings for physical activity and screen time23. These variations might explain the inconsistent results of systematic reviews examining socio-economic inequalities in health behaviors among young people20,21,24,25and are in line with the equalization hypothesis, which posits that health disparities decrease in adolescence because of the growing influence of peers over the family26. These results suggest that public health interventions need to be tailored, targeting children from lower socio-economic backgrounds and adolescents, who are at greater risk for non-adherence to health behavior recommendations.

Most children in our sample did not report lasting changes in health behaviors two years after the onset of the pandemic and following the lifting of all sanitary measures. These reassuring findings could reflect both the resiliency of young people and their families, as well as the relatively light restrictions implemented by the Swiss government18. However, when examining socio-demographic patterns of change, we found an overall worsening of health behaviors among older children during the pandemic. Interestingly, compared with their more privileged counterparts, disadvantaged individuals were more likely to experience any changes, whether positive or negative. It reflects results from studies showing that adults whose financial situation deteriorated during the pandemic were more likely to experience both an improvement and worsening of health behaviors such as screen time, substance use, diet and physical activity27,28. Disruptive life events, such as the COVID-19 pandemic, can drive lifestyle shifts29. Since children with unfavorable financial situation were shown to experience a heightened impact of the pandemic than their more advantaged peers30it may explain why they were also more likely to report changes in health behaviors, whichever the direction. These results shed light on the complexity of the social impacts of the pandemic and suggest that additional contextual factors, such as family circumstances, access to green spaces, or housing, might modify the effect of the pandemic13,27.

The major strength of this study was the ability to study the correlates of both negative and positive pandemic-related changes in multiple health behaviors in a large population-based sample of children and adolescents. However, results should be interpreted in light of their limitations. As commonly observed in epidemiological surveys31, privileged individuals were more likely to participate in our study despite the random selection process (75% of mothers had a university-level education in our sample versus 48% of women aged 25–64 years old, in Geneva32), which could lead to an overestimation of the prevalence of children meeting health behavior recommendation. Additionally, the reliance on cross-sectional parent-reported data could be subject to social desirability and recall bias, particularly regarding pandemic-related changes in health behaviors. However, in the absence of objective assessment of health behaviors, parental report may be more reliable than school-aged children’s, as it was shown to correlate with objectively measured health outcomes like overweight, whereas child report was not33. Finally, no population-based cohort study of children was ongoing in Switzerland at the onset of the pandemic, which proved to be a significant limitation in assessing the pandemic’s impact on children’s health behaviors and other health-related dimensions. This gap highlights the need to establish such studies as an observatory of children’s health over time and as a baseline to examine trends following major societal events.

This report suggests that a significant proportion of children and adolescents does not adhere to health behavior recommendations in Switzerland. The COVID-19 pandemic potentially exacerbated existing patterns for older and disadvantaged children, although most children did not experience lifestyle changes. Future research should focus on understanding the reasons for this heterogeneity to identify protective factors. These insights could guide the design of tailored interventions for youth at risk of unhealthier behaviors, helping to reduce the identified social disparities. Specifically, maintaining a routine and spending time outdoors were related to a more active lifestyle during the pandemic34. Drawing on these findings, policymakers and schools should prioritize access to quality green spaces and provide affordable, convenient curricular and extracurricular activities. Additionally, interventions could promote parental awareness regarding the benefits of structured routines for children. This is crucial given the importance of lifestyle on the physical and mental health of young people, and their positive impact over the lifecourse1.

Methods

Cross-sectional data was drawn from two studies with similar recruitment and data collection methods: the SEROCoV-KIDS cohort and a COVID-19 seroprevalence study35 whose enrollments took place between December 2021 and June 2022. In both studies, children’s inclusion criteria were (1) to be aged between 6 months and 17 years old, (2) to live in the canton of Geneva, Switzerland, and (3) to have been (or have a sibling) selected from random samples of the Geneva population, or to be part of the household of a randomly selected individual for previous studies conducted by our research group. The current analysis focused on participants aged between 3 and 17 years, for whom data on pandemic-related changes in health behaviors were collected. The Geneva Cantonal Commission for Research Ethics approved the studies (IDs 2020 − 00881 & 2021 − 01973) and all methods were performed in accordance with the relevant guidelines and regulations. Written informed consent was obtained from participants parent’s or legal guardians, as well as from adolescents aged 14 years or older.

Upon enrollment, between December 2021 and June 2022, one referent parent (or caregiver) per household was asked to estimate their children’s current recreational screen time, sleep duration, physical activity, and time spent in green spaces on week and weekend days, as well as whether they noticed lasting changes in these dimensions due to the pandemic (e.g. “In your opinion, has the pandemic had a lasting impact on the amount of time the child spends on screen for recreational activities?” Responses: “yes, it increased”, “yes, it decreased”, “No, it did not change”). Adolescents aged 14 and above self-reported their screen behaviors. Questions were developed by the research team and reviewed by an expert in survey design (Supplementary Table 2). Adherence to health behavior recommendations was assessed using age-specific thresholds from the World Health Organization36,37 or when not available, from the Canadian 24-Hour Movement Guidelines38. Specifically, children aged 3–4 years who engaged in at least 90 min of physical activity per day, and those aged 5 years or older who engaged in at least 60 min per day, were considered to adhere to the recommendations for physical activity. Screen time recommendations were met if daily screen use was one hour or less for 3–4 years old children and two hours or less for older children. Sleep duration was deemed adequate if it ranged from 10 to 13 h per day for children aged 3–4 years, 9 to 11 h for those aged 5–13 years, and 8 to 10 h for adolescents aged 14–17 years. Tertiles differentiating between average to high and low time spent in green spaces were used, as no guidelines exist for this behavior (Supplementary Table 2). Demographic and socio-economic characteristics such as age and sex of children, household financial situation (“very good”, “good”, “average-to-poor”), parents’ country of birth (“at least one parent born in Switzerland”, “parents born outside of Switzerland”) and highest educational level (“college or higher”, “lower than college”) were included as potential correlates.

Regarding the first study aim, the overall prevalence of children not meeting behavior recommendations for screen time, physical activity, time spent in green spaces, and sleep duration was weighted according to the Geneva population’s age and sex distribution39. Time spent engaging in health behaviors according to demographic and socio-economic characteristics (age, sex, parents’ birth country, parents’ highest education, household financial situation) and the corresponding non-adherence to recommendations were estimated with marginal prediction from age- and sex-adjusted regressions. To address the second aim, separate analyses were conducted to assess the association between each demographic and socio-economic characteristic and adherence to the recommendations for each behavior. Generalized estimating equations (GEE) adjusted for age and sex (and physical limitations for physical activity) and following a binomial distribution were estimated with the R geepack package40 to account for the household clustering of participants, as some children were siblings. An interaction term was added between age and each of financial situation, parental education, and parental country of birth to capture how the associations with these factors vary across the wide age range under study. Regarding the third aim, demographic and socio-economic correlates of changes in health behaviors due to the pandemic were modelled with age- and sex-adjusted multinomial GEE with no change as the reference category using the R multgee package41. This enabled the identification of specific determinants of both improved and impaired health behaviors, compared to no change. All analyses relied on complete cases.