In recent years, excessive ST for preschool children has become an increasingly salient public health concern that can have profound effects on young children’s physical and mental wellbeing. This study implemented a meta-analysis to synthesize existing studies and quantify the impact of current interventions aimed at reducing ST in preschoolers, as well as to explore the factors that may affect the effectiveness of these interventions. It was found that although interventions designed to reduce ST in preschool-aged children have a moderate impact overall, there is evidence of publication bias present in the literature[17]. Moreover, the effect of interventions targeting ST is greater in preschool children compared to children and adolescents, indicating that health-related behaviors, such as those involving screen devices, may be more amenable to change in preschoolers[18]. These findings suggest that early intervention to modify screen habits may be particularly beneficial for young children’s health and development.
Subgroup analysis of the study participants revealed that the gender of children moderated the effect of the ST intervention, consistent with previous research[19] that boys benefited more from the intervention. It is possible that boys may have greater interest in electronic media and spend more time on screens than girls[20]. Compared to the general population, ST intervention was more effective for high-risk groups such as overweight/obesity, excessive ST, and Latin American populations. This may be due to these high-risk children having longer baseline ST, greater intervention space for modification, and high sensitivity to intervention. Previous studies had also shown that the incidence of excessive ST is higher in obese individuals compared to those of normal weight[21]. These findings suggest that intensive intervention in at-risk populations may be a key approach to improving the efficiency of ST interventions.
Turning to the specific intervention strategies or measures, interventions that took schools as their main trial site appeared to reduce the ST of preschool children. These interventions primarily covered diet, ST, physical activity, and others, improving the self-efficacy levels of children and parents through school-organized group education activities, parent seminars and parent-child interaction activities, home-school cooperation and homework assignments, family screen rules and other family-based interventions[19, 22]. The effects of these interventions, however, varied widely between different studies, possibly because some intervention programs only provided health education materials to parents without strict supervision, and the intervention effects were largely influenced by the parental compliance. In terms of the intervention period, the effect seemed better for interventions lasting ≥ 6 months compared to those lasting < 6 months, consistent with previous studies[23]. For the intervention pattern, implementation was variable among individuals, and it was difficult to ensure the effective implementation and continuous participation of parents despite offline assistance (such as telephone consultation, discussion group, and information material support) being convenience and cost-effective. Additionally, subgroup analysis results suggest that interventions based on behavioral theory (such as social cognition theory, self-efficacy theory, self-determination theory, chronic care model, etc.) and directly targeting children rather than parents were more effective.
The results further indicate that the treatment received by the control group has an impact on the final pure effect size of the ST intervention. The effect size of the intervention using the blank control (without treatment received by control group) was greater than that of the treated control group. This may be because imposing certain interventions (even simple health education) generally narrows the gap between the actual effect of the intervention group and the control group, resulting in a reduced relative effect size of the intervention group compared with the control group.
Limitations of this study include: (1) Heterogeneity was observed in the results due to the diversity among study participants, study designs and intervention strategies. (2) The interventions studied were mainly implemented in the United States or developed countries (such as Canada, Australia, Sweden, etc.), with most of them located in urban areas. Therefore, generalizing our results to other populations such as developing countries and rural areas should be done with caution. In the future, more targeted and higher quality randomized controlled trials should be designed based on behavioral theory to explore effective strategies of ST intervention in preschool children, reduce excessive use of electronic screens, and promote their physical and mental development.