Changes and correlates of screen time in adults and children during the COVID-19 pandemic: A systematic review and meta-analysis

Summary Background Screen time has increased as a result of the COVID-19 pandemic, and several correlates have been associated with these increases. These changes, however, have not been aggregated. It was the aim of this review to (a) aggregate changes in screen time in adults and children, and (b) report on variables in relation to screen time during the COVID-19 pandemic. Methods A systematic review of major databases was undertaken for studies published from inception to 06/12/2021, using a pre-published protocol (PROSPERO ID: CRD42021261422). Studies reporting (a) screen time pre-versus-during the pandemic, (b) screen time percentage change, or (c) correlates of screen time during the pandemic were included. A random effects meta-analysis was undertaken with subgroup analysis by age group and type of screen time. Findings After review, 89 studies (n = 204,734; median age=20·6; median female=53·3%) were included. The majority of studies were cross-sectional. With regards to total screen time, primary aged children (6–10 years) reported largest increases (1·4 hrs/day; 95%CI 1·1–1·7), followed by adults (>18 years; 1·0 hrs/day; 95%CI 0·7–1·2), adolescents (11–17 years; 0·9 hrs/day; 95%CI 0·3–1·5), and young children (0–5 years; 0·6 hrs/day 95%CI 0·3–0·9 hrs/day). For leisure screen time (non-work/non-academic), primary aged children reported largest increases (1·0 hrs/day 95%CI 0·8–1·3), followed by adults (0·7hr/day 95%CI 0·3–1·2), young children (0·6 hrs/day; 95%CI 0·4–0·8), with adolescents reporting the lowest increase (0·5 hrs/day 95%CI 0·3–0·7). Several correlates were associated with reported increases in screen time, including adverse dietary behaviours, sleep, mental health, parental health, and eye health. Interpretation Pooled evidence suggest that primary aged children reported the highest increase in both total and leisure screen time during COVID-19. It is recommended that screen time should be reduced in favour of non-sedentary activities. This study has the potential to inform public health policy and future guidance regarding screen time, and to inform future research in this area. Funding No funding was received for this study.


Introduction
In March 2020, the World Health Organization (WHO) declared the COVID-19 outbreak a global pandemic, and as of 19th January 2022, over 325,000,000 confirmed cases have been diagnosed in more than 130 countries and areas, resulting in approximately 5500,000 deaths. 1 Since the beginning of 2020, more than 100 countries have enforced some kind of social distancing measures to reduce the rate of COVID-19 transmission, commonly called 'lockdown'. 2 The severity of lockdown has varied from country to country, even region to region, with some countries limiting the distance people could travel from their homes, and some banning any unnecessary outdoor activity. 2 These lockdowns have undoubtedly impacted the way in which people work, travel, and spend recreational time. For example, a systematic review reported in the initial phases (in the year 2020) of the pandemic, the majority of adults and children had increased time in sedentary behaviours, defined as any waking behaviour with an energy expenditure of ≤ 1¢5 Metabolic Equivalents (METs) whilst in a sitting or reclining posture, 3 with concurrent decreases in physical activity, 4 although the study did not stratify the type of sedentary behaviour. One type of sedentary activity that has increased substantially during the pandemic is screen time − adults who are now working from home are increasingly using online platforms for work meetings, and children in a number of countries have been taking part in their educational classes online, 5 with an estimated 1.37 billion children being at home in March 2020. 6 To date, however, these changes in screen time have not been aggregated, which is likely due to a paucity of homogeneous data. On the other hand, several correlates have already been associated with increases in screen time in adults and children independently, including unfavourable dietary choices (such as positive associations between screen time and increases in alcohol and sweetened foods consumption), 7,9 adverse physical and mental health (headaches, anxiety, and poor mental health outcomes related to problematic smartphone use, (such as anxiety, insomnia, increased perceived stress, poor educational attainment and decreased overall quality of life), 10−12 and eye related correlates (such as dry eye syndrome, heavy eyelids, and increased myopia). 13−16 Furthermore, a systematic review has reported consistent associations between smartphone and/or tablet use and several measures of sleep outcomes in children, including significant associations between device use and poor sleep quality, quantity, and excessive daytime sleepiness. 17 Despite these negative associations, however, problematic screen time behaviours are not consistently reported in studies measuring screen time, with authors arguing that problematic screen time and screen time should be measured concurrently using well established tools, such as the Smartphone Addiction Scale. 18,19 In view of these reported associations between screen time and various negative outcomes, it is important to understand the effect that COVID-19 pandemic has had on screen time behaviours and how this has impacted on different correlates. To date, these changes in screen time during the pandemic and correlates have not been systematically reviewed and discussed. It was therefore the aim of this review to: 1. Aggregate and report on the changes in screen time in adults and children independently.
2. Report on all correlates that have been measured in relation to screen time during the COVID-19 pandemic.
This study has the potential to inform public health policy and guidance regarding screen time, and to inform future research in this area.

Protocol and registration
This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 20 and has been registered with the international prospective register of systematic reviews (PROSPERO protocol ID CRD42021261422). Note that there were no deviations from the published protocol.

Search strategy
Databases were searched from inception to 06/12/2021 including Pubmed; Embase; Scopus; OpenGrey; Psycinfo; ERIC; Child Development and Adolescent Studies; and Web of Science, using the following search terms: (screen time OR sedentary behaviour OR digital screen time OR sitting time OR screen-time OR gaming OR television OR smartphone OR computer time) AND (SARSCoV-2 OR 2019-nCoV OR COVID-19 OR coronavirus OR COVID19 OR coronavirus 19) No other limiters were applied.

Research in context
Evidence before this study Sedentary behaviour has increased because of the COVID-19 pandemic. It was the aim of this review to pool and report on increases in screen time during the COVID-19 pandemic, and review associations between screen time and correlates. Pubmed, Embase, Scopus, PSYCInfo, ERIC, Child development and adolescent studies, Web of Science and Opengrey were searched using terms relating to "screen time", "digital screen time", "sedentary behaviour", "sitting time" and COVID-19 from inception to 6/12/2021.

Added value of this study
This review found that all age groups increased their total screentime. Primary aged children (6−10 years) reported largest increases, followed by adults (>18 years), adolescents (11−17years), and young children 0 −5 years). Leisure screen time also increased in all aged groups, with primary aged children reporting the largest increases, followed by adults, young children, and adolescents. Several correlates were associated with reported increases in screen time, including adverse dietary behaviours, sleep, mental health, and eye health.

Implications of all the available evidence
This review provides evidence that screen time should be reduced wherever possible to negate potential adverse outcomes, and, instead, non-sedentary activities should be promoted.
Results of searches were imported in a bibliographic database, with duplicates removed automatically. Titles and abstracts of the remaining studies were independently screened for inclusion by two authors (MT; EI). Following title and abstract screening, the full texts of all potentially eligible papers were reviewed independently by two reviewers (MT,EI) before making a final decision on eligibility, with a senior reviewer (SP) mediating any disputes. The following section describes the inclusion and exclusion criteria: Population. All types of population (e.g., age, country) were considered, using any study design.
Intervention(s)/exposure(s). All studies that reported pre vs during screen time usage during COVID-19, or studies that reported associations between any outcome and screen time during COVID-19.
Comparator(s)/control(s). In studies that measured pre vs during COVID-19 screen time usage, the pre COVID-19 screen time data must have been collected prior to November 2019. Furthermore, all data were stratified into two group: adults (>18yrs), and children (<18yrs). Children were also stratified into three sub-groups were available: adolescents (11−17years), primary aged children (6−10years), and young children (<5 years).
Outcomes. Studies had to report one or more of the

Data extraction
Data were extracted by two reviewers (MT & RD) and included: first author; study title; publication date; country; study type; outcome type; outcome effect size; sample size; and participant characteristics.

Risk of bias assessment
Risk of bias was assessed by two independent researchers (MT; EI) using the Newcastle Ottawa Scale (NOS) for cross-sectional studies. 21,22 There are 3 parts in which studies are assessed and stars awarded: (i) selection (max. 5 stars) -representativeness of the sample, sample size, non-respondents, and ascertainment of the exposure (risk factor); (ii) comparability (max. 2 stars)participants in different outcome groups are comparable; (iii) outcome (max. 3 stars)-assessment of outcome, and statistical test. Scores can range from 0 to 10 stars, with higher scores indicating better quality research. Any discrepancies over the final risk of bias verdict were solved by consensus, with involvement of a third review author (SP) where necessary.

Statistical analysis
To aggregate screen time changes pre vs during COVID-19, a random-effects meta-analysis was conducted using the DerSimonian and Laird method, with studies weighted according the inverse variance, using Comprehensive Meta-Analysis. 23 The meta-analysis was conducted using the following steps: (1) Pre and during COVID-19 screen time (hrs/wk.), standard deviations were imputed, and means differences with standard errors were calculated. Note all analyses were stratified as adults (>18) and children (<18). Children were further stratified into three groups: (a) Adolescents (age 11−17); (b) children (age 6−10); and (c) young children (age 0−5). Note that only studies of the same study design were pooled.
(2) Heterogeneity between studies was assessed using the I 2 statistic, 24 with 0−50% being considered low, 51−75% moderate, and >75% being considered high heterogeneity. If pooled results showed high heterogeneity, sub-group analysis was used to find the potential sources.
(3) Publication bias was assessed with a visual inspection of funnel plots and with the Egger bias test. 25 As per the recommendations by Fu et al. 26 and Sterne et al., 27 these tests were only conducted if the number of studies in each analysis exceeded ten. If significant publication bias (Egger's p=<0.05) was present, a trim-and-fill analysis was conducted. 28 (4) Furthermore, sensitivity analyses were conducted to assess the robustness of analyses through the one study removed method.
Mean percent changes in screen time (increased, remain constant, and decreased) and SDs were also calculated using a random effects model, with studies weighted based on the inverse of the variance.
Due to anticipated heterogeneity in measurement types, all associations were aggregated in a narrative synthesis.

Certainty of evidence
To ascertain the certainty of the evidence, the Grading of Recommendations, Assessment, Development and Evaluations 29 (GRADE) framework was used.

Role of the funding source
No funding was received for this study. All authors confirm that they had full access to all the data in the study and accept responsibility to submit for publication.

Results
The initial search yielded 7283 results, of which 1403 were removed as duplicates, leaving 5880 articles to be screened at the title and abstract level. Of these, 408 were selected for full text screening. After the full text assessment, 89 articles were selected for inclusion (total n 204,734; median age=20¢6; median percentage female=53¢3%). All but one of the included studies were cross-sectional in study design, with the one study being longitudinal. The full PRISMA diagram is shown in Figure 1. Of these, 46 studies included data regarding adults, 7

Associations between screen time and multiple correlates
Adults. In  Articles to diet and smoking, of which 35% (10/29) were statistically significant.
In outcomes that measured gaming, 50% (1/2) of univariate correlations were statistically significant. The significant association was a negative correlation between the use of gaming consoles and self-regulation around eating (r= À0¢15; p = 0¢04), 62 and the non-significant association was 'gaming on a computer' and self-regulation around eating (r= À0¢06; p=NR). 62 Regarding cell phone use, 17% (1/6) of outcomes yielded significant associations, with increases in cell phone use being significantly associated with the consumption of sweetened foods (OR=1¢78 95%CI 1¢18 −2¢67). 8 Increases in cell phone use was not significantly associated with alcohol consumption, increased desire to drink alcohol, increased in smoking or the desire to smoke more.
Increases in 'video gaming' were associated with increases in appetite (r = 0¢12; p=<0¢001), and late snacking during the night (r = 0¢09; p = 0¢02). Non-significant findings included decreases (or loss of): appetite, protein intake, increases in sweets and unhealthy foods, not caring about eating fruits and vegetables, and frequent snacking between meals.

Discussion
This systematic review and meta-analysis, including 89 studies, examined the pooled reported changes in screen time from before the COVID-19 pandemic, and narratively examined correlates associated with screen time during the COVID-19 pandemic.
The results from the meta-analysis showed that all groups significantly increased both their total and leisure screen time. Children of primary age had the largest increase in both total and leisure screen time, followed by adults, with adolescents and young children yielding the smallest increase. Furthermore, 51% of adults and 67% of children reported increases in total screen time, and 52% of adults and 60% of children reported increases in leisure screen time. These results are in line with research showing increases in sedentary behaviours during the COVID-19 pandemic, 4 although this study is the first to examine screen time independently. Although the increases in total screen time could be partially caused by increasing time in front of a screen for work or academic purposes (such as increases in online meetings and education), the increases in nonacademic screen time in children are concerning. Indeed, it has been reported in pre-COVID-19 reviews that screen time is associated with several unfavourable outcomes, such as increased BMI, increased maternal depression, lower cognitive stimulation at home, decreased quality of life, lower self-esteem, and anxiety. 112,113 A recent systematic review and meta-analysis has also concluded that smart device exposure may be associated with increased risk of myopia in children, indicating that increases in screen time during COVID may also lead to increased prevalence of myopia. 16 Furthermore, a recent longitudinal study has reported that screen time at the age of 4 is negatively associated with mathematic and literacy grades at the age of 8, 114 suggesting that screen time at a younger age could affect future academic achievement. Although the absolute screen time adults and children should adhere to are under debate and not universally agreed upon, there is a growing consensus that leisure screen time should be minimised in favour of physically active pursuits. 115 Moreover, the UK Chief Medical Officer recommends that parents of children (of all ages) proactively consider if a child's screen time if affecting sleep, physical activity, and snacking. 116 Several negative food behaviours were associated with increases in screen time in both adults and children. These included associations between increased screen time and 'unhealthy diet changes', and associations between increased computer, television, and cell phone use and increases in sweet food consumption. Further, increases in computer time for self-directed learning was found to be positively associated with eating related self-regulation while increases in TV time were found to be negatively correlated, and other types of screen time, including computer gaming and overall screen time, were not significantly associated. Importantly, there were more significant associations between increases in screen time in children than in adults, suggesting that appropriate interventions may benefit children more. This broadly concurs with pre-pandemic reviews showing sedentary behaviours (including screen time) are associated with less healthy diets, including lower fruit and vegetable consumption, higher energy dense drinks, fast foods and higher total energy intake in both adults and children. 117,118 As the pandemic has resulted in increases in screen time, it is recommended that public health guidance on reduced screen time and healthy dietary behaviours during it be promoted, with a focus on targeting parents and children.
Alcohol use during the pandemic was shown to be negatively associated with increased computer time, however increased television use was associated with an increased desire to drink alcohol (but not with increased consumption). Although other reviews have reported increases in alcohol consumption during the pandemic, 119 results from this study suggest that these increases are not associated with screen time. Longitudinal study is warranted to examine these behaviours. Furthermore, all correlates related to smoking (smoking and desire to smoke) were not significantly associated with any type of screen time use, indicating that COVID-19 screen time did not affect smoking habits.
This review found that several eye related correlates were associated with screen time. In adults, increases in screen time was consistently associated with dry eye syndrome, which broadly agrees with previous literature in both a COVID-19 and non-COVID-19 context. 120,121 It was also found that more than 6 h of screen time/day was associated with several symptoms of digital eye strain, including tearing, eye strain, dryness, heavy eyelids, red eyes, eye itchiness, burning sensation in the eye, sensitivity of bright light, difficulty focussing, eye pain, the feeling of a foreign body in the eye, and excessive blinking. These results concur with pre-pandemic reviews that have found associations between dry eye syndrome and screen time. 120 It has previously been reported that the possible mechanisms for this could be reduced blink rates, meibomian gland dysfunction, and corneal phototoxicity, most likely to be multifactorial, 120 and further study is warranted, especially longitudinal study to establish temporal relationships.
In children, increased screen time was significantly associated with myopia, with almost all associations being significant. Indeed, every stratified type of screen time significantly correlated with increases in myopia across multiple studies, with the exception of 'multiple devices'. This is in agreement with a recent meta-analysis that reported associations between screen time and myopia, 16 however other reviews have reported mixed results. 122 Although the results from this review cannot determine temporal relationships due to the cross-sectional design of included studies, these results concur with longitudinal studies that have found that increased screen time may be a casual factor of myopia in children. 123 It is recommended that children minimise screen time (particularly using screens where the child is very close to the screen, such as tablets and phones) use to potentially prevent dry eye and increased risk of myopia. As higher odds of myopia were found in increased smartphone devices, it is also recommended that any e-learning be conducted on a larger screen further away from the eyes, and not on a smartphone device (or similar), to negate these risks.
In adults, studies that measured overall screen time subjectively mostly found significant associations, however the two studies that objectively measured screen time found no significant associations. Regarding different types of screen time, one study found that TV time was associated with COVID-19 related anxiety, with other studies finding no association between TV time and overall anxiety. Due to these conflicting results, it is difficult to come to conclusions regarding screen time and anxiety. This is broadly in agreement with other systematic reviews examining sedentary behaviour (including screen time) and anxiety in adults. 124 We agree with Teychenne, Costigan and Parker 124 that large longitudinal studies are needed to comprehensively examine this possible association.
In children, there was a general consensus across included studies that overall screen time was not associated with anxiety, however this was not the case regarding stratified screen time. Indeed, studies reported associations between anxiety and leisure screen time, online gaming, internet browsing, TV and social media use, with no stratified type of screen time yielding non-significant results. This is in agreement with other large longitudinal studies that have found associations between screen time and anxiety in adolecents, 125,126 however more research is needed in children of younger ages.
In adults, studies reported conflicting results, with different studies reporting significant associations between overall screen time and depression in both directions (e.g. one study showed a protective effect), with other studies reporting no association. The only stratified type of screen time was TV, which was found to be significantly associated. It is likely that these conflicting results are because of heterogeneity in populations, measurement tools, and statistical methodology. Although previous systematic reviews have reported positive associations between screen time and depression in adults, in one review the significance of results changed when stratifying according to gender (only females yielded a significant association). 127 Furthermore, other studies have found that only moderate to severe depression is associated with screen time. 128 It is therefore difficult to conclude whether depression is associated with screen time during the COVID-19 pandemic − further studies with heterogeneous measurement tools would be highly beneficial.
In contrast to adults, the studies that examined screen time and depression in children all found significant associations, suggesting a link between screen time and depression in children with a higher level of certainty. This is in agreement with previous literature that has concluded that screen time is associated with depression in children, with a significant (non-linear) dose response relationship. 129 Although the direction of association is difficult to ascertain, it is recommended that parents monitor screen time usage in children to prevent or identify possible depressive symptoms.
Studies that examined mood changes yielded nonsignificant results in adults but showed several mood changes that were significantly associated with screen time in children. These significant associations, across several studies included increased aggression, irritability, frustration, temper tantrums, and mood disturbances. When stratified according to type of screen time, personal devices, such as mobile phones and tablets were associated with behavioural problems in children, whereas TV time was not. This concurs with a pre-pandemic umbrella review that found weak evidence for associations between poor mental health outcomes and screen time in children and adolescents. 130 As with adults, it is currently unknown as to the mechanisms that drive these associations, and whether they are chronic or acute. For example, a review examining longitudinal studies found no longitudinal associations between increased screen time as a child and most long-term mental health conditions. 131 In adults, most studies reported significant (direct whilst indirect were not significant) associations between several types of screen time (including overall screen time) and loneliness, however in one study this was only found in people without concurrent depression. This is in broad agreement with other pre-COVID studies that have found associations between screen time and loneliness, with some studies reporting that decreases in screen time (in particular social media use) can decrease loneliness. 132 In children, several stress-related correlates were significantly associated with screen time, while others were not. Although a significant association was found between overall screen time and stress, this was found in only one study. Gaming related screen time was found to be associated with COVID-related worries, but not COVID-related stress. Social media use, on the other hand, was found to be associated with COVIDrelated stress, but not with COVID-related worries. Smartphone use was associated with psychological distress in one study. Lastly, TV time was not significantly associated with any form of stress in any study. Overall, the evidence is mixed, however previous studies have reported associations between screen time and stress in children. 133 This could be because there were no more than one outcome examining the same correlate (except from TV use), and further research is warranted.
Other significant correlates of mental health in adults and children included several types of screen time being associated with general mental health and wellbeing, which concurs with several previous studies that have concluded similar results. 127,133 Although when stratified according to type of screen time and type of mental health correlate, it is clear that several of the included studies agree with pre-COVID studies that increases in screen time are linked to negative mental health outcomes. 127,133,134 It is therefore recommended that screen time be reduced wherever possible (for example, leisure time screen time) to negate these negative outcomes.
Overall screen time was consistently associated with decreases in physical activity in adults, however conflicting results were found regarding TV time. Furthermore, gaming and social media use were both found to correlate with physical activity, however smartphone use and PC/computer/tablet use were not. Weight gain was associated with time spent lying in front of a TV screen, yet in a different study overall BMI was not associated with overall screen time. Few previous studies have reported associations between screen time and physical activity levels, however studies have reported negative outcomes in adults with high screen time and low physical activity levels, including health related quality of life. 135 Although screen time is generally classified as a sedentary behaviour, there are types of screen time that promote physical activity, including exergaming (a type physical activity that is technology-driven, and often includes an element of screen time), a type which has not been explicitly identified in this review. Indeed, exergaming has been shown to reduce anxiety levels and increase physical activity levels, 136 and has been postulated as a potential source of physical activity during the COVID-19 pandemic, particularly in times of quarantine. 137,138 Primary studies regarding the efficacy and accessibility of exergaming as an alternative to sedentary based screen time behaviours during the COVID-19 pandemic are warranted.
Significant associations between screen time and physical activity in children were conflicting, with some studies reporting negative associations between physical activity and overall, leisure, and education screen time, whereas other studies reported null results. The conflicting results could be due to several factors, including reporting biases and statistical methodology. Regarding sedentary behaviour, screen time was consistently associated in children, however changes in BMI and weight gain were not associated with screen time in any study. This concurs with much of the literature that has found similar associations, predominantly because screen time is usually conducted while in a sedentary position. 130 It also agrees with previous reviews that have shown large increases in sedentary behaviour during the pandemic. 4 Because several previous studies have found significant negative associations between screen time and physical activity in children of all ages, increases in physical activity and corresponding decreases in screen time being recommended. 139−141 In adults, studies agreed that screen time was not associated with sleep or fatigue correlates, including sleep time. This is in conflict with pre-COVID studies that have found association between screen time and sleep time in adults. 142 This conflict may be because people have been reported to experience sleep disturbances as a result of the COVID-19 pandemic. 143 Conversely, in children, several studies agreed that increases in screen time were associated with sleep problems, including sleep duration and sleep disorders. The only exception to this appears to be TV time, which was not found to be associated with sleep problems. This is in broad agreement with much of the literature that reports disturbed sleep patterns with increases in screentime. 17,18,130 All of these correlations, however, did not adjust for other known correlates of sleep disturbances, such as anxiety and depression. 144 Further examination of potential mediating factors is warranted.
Several parental anxiety and parental stress correlates were associated with different types of screen time. Furthermore, conflicts with parents were significantly associated with increases in screen time, although these results should be treated with caution as several correlates were only measured in one study. This concurs with pre-pandemic reviews that have reported that parental stress is associated with child screentime. 112,145 One possible reason for this finding is that COVIDrelated parental COVID-related stress is having a direct impact on child screen time − further longitudinal studies are required to establish temporal relationships.
There was a consensus across studies that screen time was associated with negative screen related behaviours, including problematic gaming and social media use. This is in agreement with the literature, and is a concerning finding because previous studies have reported that problematic screen use is associated with several negative mental health outcomes. 12 Furthermore, it has been reported in a recent systematic review and meta-analysis that problematic smartphone behaviours are increasing globally, 146 however the majority of included studies (as well as previous literature concerning screen time) did not include problematic usage in their studies. 12 It is recommended, therefore, that both screen time and problematic screen time behaviours be monitored in children closely, and sedentary based leisure time screen time be reduced in favour of other activities that have been shown to have positive effects on mental and physical health, including physical activity and exergaming (especially if people are subject to further periods of restrictions).
Although this is the first review examining screen time changes during the COVID-19 pandemic in adults and children, the results of this review should be taken within its limitations. Firstly, there was high heterogeneity in the meta-analysis, which we could not fully explain. It is likely that differing methods of measuring screen time, and different populations, contributed to this. Furthermore, there was a large range in the quality of studies included, which may have added to the heterogeneity. Secondly, although several significant effect sizes were found spanning a wide variety of unfavourable outcomes, several non-significant findings were also found, possibly due to the heterogeneous nature of the included populations and the measures used. Thirdly, the methods of measuring screen time were highly heterogeneous, with some studies using self-report, others using parental report, and others using objective reports − future research should use either validated measures of screen time and/or problematic screen time use, or objective measures of screen time wherever possible. Lastly, although there were several correlates that concurred between studies, other significant correlates were based on one effect size from one study, and therefore the results of these should be treated with caution.
In conclusion, this review has found evidence that both overall and leisure screen time increased during the COVID-19 pandemic, with children of primary school age yielding the highest increases. Furthermore, several unfavourable correlates have been reported to be associated with increases in screen time in both adults and children, including several mental health correlates. In addition to the well-reported benefits of physical activity, it is recommended that leisure screen time should be reduced in favour of non-sedentary activities, including physical activity, especially in children. If, however, physical activity is difficult (for example, in periods of restrictions limiting the ability to go outdoors), screen related physical activity such as exergaming may yield favourable outcomes.

Data sharing statement
All data used in this research was gathered from already existing research. No original data was used for this study. Data extraction tables and figures are available from MT.

Declaration of interests
None to report.

Funding
No funding was received for this study.

Supplementary materials
Supplementary material associated with this article can be found in the online version at doi:10.1016/j. eclinm.2022.101452.