28 The effect of screen time on cardiometabolic risk in young children: A longitudinal cohort study

Young children in Canada do not meet the current screen time recommendations (< 1 hour for children 3 to 4 years; < 2 hours for children 5 years and older). While increased screen time is associated with physical and psychological health consequences in children, very little is known regarding the association with cardiometabolic risk (CMR) in young children. This study defined screen time as the use of TV, DVD/video, computer/laptop, video games, and handheld devices (e.g., cell phone, iPad Touch, iPad, etc.) on a typical weekday and a weekend day. The primary objective of this study was to examine the association between screen time and total CMR score [sum of age- and sex-standardized z-scores of systolic blood pressure (SBP), glucose, triglycerides, high-density lipoprotein (HDL) cholesterol, and waist circumference (WC) / square root of 5]. The secondary objectives were to examine associations between screen time and individual CMR factors including waist-to-height ratio and non-high-density lipoprotein (non-HDL) cholesterol. A longitudinal cohort study was conducted with young children 3-to-6-years (n = 1,706). Children with repeated measures of both screen time and CMR were included in the study. Generalized estimating equation (GEE) multivariate linear regressions were conducted to evaluate the associations. Among those aged 3-to-4-years, the proportion of children meeting the screen time guidelines was 10.8%, with 61.9% of those being females, and 56.3% males. In children over the age of 5, 37.7% met the screen time guideline, with no differences by sex. No statistically significant associations were found between screen time and total CMR nor the individual factors of glucose, SBP, triglycerides, WC, and waist-to-height ratio (p > 0.05), after adjusting for confounders. A small and statistically significant association between screen time and non-HDL cholesterol was reported (B = 8.80x10-3; 95% CI: 1.61x10-3, 1.59x10-2; p = 0.02). Studies are needed to understand how exposure to screens at a very young age impacts CMR beyond early childhood. The significant association ascertained between screen time and non-HDL cholesterol should be examined further over time, and may contribute to the development of appropriate health promotion interventions to examine how decreasing screen time can decrease the risk of non-HDL cholesterol among young children as they age.