Screen-based Media and Energy Intake in New Zealand Youth: Experimental Effects of Screens on Energy Intake and an Assessment of the Role of the Family and Home-Screen Environment on Behaviours

Abstract

Background: Lack of effectiveness in screen-use interventions may be due to a failure to focus on the mechanisms linking screens and overweight, failure to keep up-to-date with changes to the environment, and too large a focus on the individual. Aim: To assess effects of traditional and emerging screen-use behaviours on energy intake (EI), and describe the modern screen environment in New Zealand. Methods: Section one consisted of a systematic review and two laboratory studies comparing EI between (1) traditional screen activities (watching television [TV], recreational computer use, and video game (VG) play), in males aged 9-13 years (n=20), and (2) single-screen use (watching TV) and multi-screen use (watching TV and access to a tablet computer and cell phone), in male and females aged 13-18 years (n=78). Section two consisted of a systematic review, an online parent survey (n=230), and an online adolescent (n=218) survey, which investigated the home screen environment, and parental and adolescent attitudes towards screens. Results: The first review showed that screen time was associated with increased EI; however, research tended to focus on TV’s. In study 1, total EI was significantly greater in the TV versus computer condition (+136 kcal; 95% CI 4, 267; p=0.04), with a trend towards greater EI in the TV versus VG condition (+125 kcal; -6, +255; p=0.06); however, EI did not differ between the computer and VG conditions (-11 kcal; -142, +121; p=0.87). In study 2, total EI did not differ between the multi-screen and single-screen groups (difference +77 kcal; -166, +320). The second systematic review found that active parent/family involvement may be necessary in screen-time interventions aimed at children and adolescents. A significant correlation between average parental screen time and average adolescent screen time (R2=0.726; p<0.001) was found in the surveys, and cell phone and computer use were the two most popular screen-based activities reported by adolescents. Discussion: A comprehensive, evidence-based approach to reduce screen use is proposed, whereby the focus of the intervention is moved from the individual child to the family unit, and both total screen time and specific screen-use behaviours shown to impact negatively health are targeted.