Summary: The impact of screen‐based devices on children's health and development cannot be properly understood without valid and reliable tools that measure screen time within the evolving digital landscape. This review aimed to summarize characteristics of measurement tools used to assess screen time in young children; evaluate reporting of psychometric properties; and examine time trends related to measurement and reporting of screen time. A systematic review of articles published in English across three databases from January 2009 to April 2020 was undertaken using PROSPERO protocol (registration: CRD42019132599) and Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. Included articles measured screen time as outcome, exposure, or confounder in children 0–6 years. The search identified 35,868 records, 1035 full‐text articles were screened for eligibility, and 622 met inclusion criteria. Most measures (60%) consisted of one to three items and assessed duration of screen time on a usual day. Few measures assessed content (11%) or coviewing (7%). Only 40% of articles provided a citation for the measure, and only 69 (11%) reported psychometric properties—reliability n = 58, validity n = 19, reliability and validity n = 8. Between 2009 and 2019, the number of published articles increased from 28 to 71. From 2015, there was a notable increase in the proportion of articles published each year that assessed exposure to mobile devices in addition to television. The increasing number of published articles reflects increasing interest in screen time exposure among young children. Measures of screen time have generally evolved to reflect children's contemporary digital landscape; however, the psychometric properties of measurement tools are rarely reported. There is a need for improved measures and reporting to capture the complexity of children's screen time exposures.

Little is known about the influence of parental attributes and parental screen time behaviours on pre-schooler’s screen time and weight status in low-to-middle income countries. The purpose of this study was to examine the relationships between parental screen time, parental self-efficacy to limit screen time, child screen time and child BMI in preschool-aged children in Brazil. Three hundred eighteen parent-child dyads from Caruaru, Brazil completed a survey measuring sociodemographic data, weekday and weekend screen time, and parental self-efficacy for limiting screen time. Height and weight were measured and used to derive BMI and BMI percentile. Observed variable path analysis was used to evaluate the relationships between the parental and child variables. Analyses were conducted for screen time on weekdays and weekend days. Parental screen time was positively associated with child screen time, either directly (weekdays = β = 0.27, p < 0.001, weekends = β = 0.24, p < 0.001) or indirectly through reduced self-efficacy to limit child screen time (weekdays = β = − 0.15, p = 0.004, weekends = β = − 0.16, p = 0.004). After controlling for household income, parental occupation, and parental BMI, greater child screen time on weekends, not weekdays, was associated with higher child BMI percentile (β = 0.15, p = 0.006). Parental screen time and self-efficacy to limit screen time are important influences on child screen time and weight status in pre-schoolers from Brazil. Reducing parental screen time and increasing parental confidence to limit screen time may be effective strategy to prevent overweight in Brazilian pre-schoolers.

Background: Heterogeneity in the outcomes collected and reported in trials of interventions to prevent obesity in the first five years of life highlights the need for a core outcome set to streamline intervention evaluation and synthesis of effects. This study aimed to develop a core outcome set for use in early childhood obesity prevention intervention studies in children from birth to five years of age (COS-EPOCH). Methods: The development of the core outcome set followed published guidelines and consisted of three stages: (1) systematic scoping review of outcomes collected and reported in early childhood obesity prevention trials; (2) e-Delphi study with stakeholders to prioritise outcomes; (3) meeting with stakeholders to reach consensus on outcomes. Stakeholders included parents/caregivers of children aged ≤ five years, policy-makers/funders, researchers, health professionals, and community and organisational stakeholders interested in obesity prevention interventions. Results: Twenty-two outcomes from nine outcome domains (anthropometry, dietary intake, sedentary behaviour, physical activity, sleep, outcomes in parents/caregivers, environmental, emotional/cognitive functioning, economics) were included in the core outcome set: infant tummy time; child diet quality, dietary intake, fruit and vegetable intake, non-core food intake, non-core beverage intake, meal patterns, weight-based anthropometry, screentime, time spent sedentary, physical activity, sleep duration, wellbeing; parent/caregiver physical activity, sleep and nutrition parenting practices; food environment, sedentary behaviour or physical activity home environment, family meal environment, early childhood education and care environment, household food security; economic evaluation. Conclusions: The systematic stakeholder-informed study identified the minimum outcomes recommended for collection and reporting in early childhood obesity prevention trials. Future work will investigate the recommended instruments to measure each of these outcomes. The core outcome set will standardise guidance on the measurement and reporting of outcomes from early childhood obesity prevention interventions, to better facilitate evidence comparison and synthesis, and maximise the value of data collected across studies.