Research report The associations between TV viewing, food intake, and BMI. A prospective analysis of data from the Longitudinal Study of Australian Children q Matthew Fuller-Tyszkiewicz a,⇑ , Helen Skouteris a , Louise L. Hardy b , Christine Halse c a School of Psychology, Deakin University, Victoria, Australia b Medical School, University of Sydney, New South Wales, Australia c Education, Deakin University, Victoria, Australia article info Article history: Received 10 August 2012 Accepted 11 September 2012 Available online 18 September 2012 Keywords: Child BMI TV viewing Dietary intake Longitudinal design Obesity abstract Objective: Despite cross-sectional evidence of a link between TV viewing and BMI in early childhood, there has been limited longitudinal exploration of this relationship. The aim of the present study was to explore the potential bi-directionality of the relationship between TV viewing and child BMI. A second- ary aim was to evaluate whether this relationship is mediated by dietary intake. Study design: Parents of 9064 children (4724 recruited at birth, 4340 recruited at age 4) from the Longi- tudinal Study of Australian Children (LSAC) completed measures of their child’s dietary intake and TV viewing habits at three equidistant time points, separated by 2 years. Objective measures of height and weight were also obtained at each time point to calculate BMI. Cross-lagged panel analyses were con- ducted to evaluate potential bi-directional associations between TV viewing and child BMI, and to eval- uate mediation effects of dietary intake for this relationship. Results: Our longitudinal findings suggest that the relationship between TV viewing and BMI is bi-direc- tional: Individuals who watch TV are more likely to gain weight, and individuals who are heavier are also more likely to watch TV. Interestingly, dietary intake mediated the BMI-TV viewing relationship for the older children, but not for the birth cohort. Conclusions: Present findings suggest that sedentary behaviours, particularly when coupled with unhealthy dietary habits, constitute a significant risk factor for excessive weight gain in early childhood. Interventions targeted at helping parents to develop healthy TV viewing and eating habits in their young children are clearly warranted. Ó 2012 Elsevier Ltd. All rights reserved. Introduction Increased sedentariness is ubiquitous in Australia and other developed countries (Healy, Matthews, Dunstan, Winkler, & Owen, 2011). Of all sedentary activities, screen time (ST; i.e., watching TV/ DVDs/videos and recreational computer use) is the most popular among young children, adolescents and adults in Australia, the US, UK, and Europe (Baxter & Hayes, 2007; Bertrais et al., 2005; Hardy, Dobbins, Denney-Wilson, Okely, & Booth, 2006; Jakes et al., 2003; Marsh, 2005). In 2004, national Australian guidelines were established which recommend children aged 5–18 spend no more than 2 h a day on ST (Commonwealth Department of Health & Ageing, 2004) and, more recently, that for children aged 2–5 years ST should be limited to <1 h per day (Commonwealth of Australia, Department of Health and Ageing, 2010). In adults there is strong evidence that prolonged TV viewing is associated independently with obesity, type 2 diabetes, and biomarkers of metabolic and cardiovascular disease (Healy et al., 2008). Recent findings have also revealed that there is an increased risk of insulin resistance among adolescent boys who exceed ST guidelines, inde- pendent of body mass index (BMI), diet, fitness, and pubertal status (Hardy, King, Kelly, Farrell, & Howlett, 2010). Furthermore, 11– 15 year olds who exceed the guidelines have significantly lower cardio respiratory fitness (Hardy, Dobbins, Denney-Wilson, Okely, & Booth, 2009). A recent systematic literature review on the impact of TV on preschoolers’ weight status revealed that of 26 relevant studies, 23 reported a positive association between hours of TV and child adiposity (Cox, Skouteris, Rutherford, & Fuller-Tyszkiewicz, 2011). Five cross-sectional studies (Dubois, Farmer, Girard, & Pet- erson, 2008; Jackson, Djafarian, Stewart, & Speakman, 2009; Janz et al., 2002; Manios et al., 2009; Vandebosch & Van Cleemput, 2007) and four prospective studies (Epstein et al., 2008; Jago, Baranowski, Baranowski, Thompson, & Greaves, 2005; Viner & Cole, 2005; Zimmerman & Bell, 2010) assessed whether the effect of TV on preschool child weight status is related to physical activity and/or diet. Taken together, the findings of these studies suggest 0195-6663/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.appet.2012.09.009 q Competing interests: The authors declare that they have no competing interests. ⇑ Corresponding author. Address: School of Psychology, Deakin University, Victoria, Australia. E-mail address: matthewf@deakin.edu.au (M. Fuller-Tyszkiewicz). Appetite 59 (2012) 945–948 Contents lists available at SciVerse ScienceDirect Appetite journal homepage: www.elsevier.com/locate/appet