Obesity Prevention and Control: Interventions to Reduce Screen Time

Evidence Gaps

What are Evidence Gaps?

Prior to and during the literature review and data analysis, the review team and the Community Preventive Services Task Force attempt to address the key questions of what interventions work, for whom, under what conditions, and at what cost. Lack of sufficient information often leaves one or more of these questions unanswered. The Community Guide refers to these as "evidence gaps." Evidence gaps can be pulled together in the form of a basic set of questions to inform a research agenda for those in the field or can be a more extensive narrative that weaves mention of gaps into a discussion generated by findings from the review.

Identified Evidence Gaps

The results from this review indicate that behavioral interventions aimed at reducing screen time are effective at reducing screen time and improving weight-related outcomes. However, important research issues remain.

• Studies do not usually make a distinction between recreational screen time and other, possibly desirable forms of screen time, such as computer use for school work, or “exergaming” (e.g., Dance Revolution™, Wii™, etc.). Further differentiation of sedentary versus non-sedentary screen time would be beneficial.
• Studies do not always report other sedentary behavior such as reading, arts and crafts, or quiet play in addition to or separate from screen time. What is the relationship between screen time and other sedentary behaviors?

Additional research is needed to identify how screen time affects health outcomes.

• What is the mechanism for screen time being associated with weight-related outcomes (e.g., advertising of food, snacking/eating while watching TV, etc.)?
• Not all screen time is undesirable (e.g., when computers are used for school work). What factors cause it to become excessive?
• What is the relationship between screen time and other health outcomes?

Increased consensus about screen time measures would be useful.

• Increased consensus about “best measures” for weight-related outcomes, physical activity outcomes, and nutrition-related outcomes would improve comparability between studies.
• Increased consensus about how screen time is measured (number of hours vs. % at a certain threshold; TV only vs. all kinds of screen time; weekend vs. weekday use)

Behavioral interventions aimed at reducing screen should be applicable in most school settings; however, possible differences in the effectiveness for specific subgroups of the population often could not be determined. Several questions about applicability remain.

• Are behavioral interventions aimed at reducing screen time as effective in preschool children, high school children, and adults as they are for elementary and middle school children?
• Are behavioral interventions aimed at reducing screen time as effective in different socioeconomic, gender, racial or ethnic subgroups?
• Are intervention effects sustained once intervention activities cease?