Changes in screen time from 4 to 7 years of age, dietary patterns and obesity: Findings from the Generation XXI birth cohort

Abstract

Background and aims Increased screen exposure is associated with unhealthy eating behaviours and obesity. Screen time (ST) changes from pre-school to school age, and associations with dietary patterns (DP) and obesity remain unknown. We, therefore, analysed ST changes from 4 to 7 years of age, associated factors, and the relation with DP and obesity. Methods and results We included 4531 children evaluated at 4 and 7 years, as part of the Generation XXI birth cohort (Porto, Portugal). ST was assessed for weekdays and weekend, and average daily time was estimated. Associations between covariates and ST changes, and between ST changes and 3 DP previously identified (Energy-dense foods, Snacking, and Healthier) were estimated by odds ratios (OR) and 95% confidence interval (95%CI), using adjusted multinomial regression models. From 4 to 7 years, 31.5% of the children decreased their ST, 21.8% increased, 16.5% maintained low (≤60 min), and 30.2% maintained high (61–120 min or >120 min) ST. After adjustment, lower maternal education (OR = 2.33, 95%CI:1.82–2.99) and lower family income (OR = 1.72, 95%CI:1.35–2.21) were associated with higher odds of increasing ST, while being a girl was associated with 35% decreased odds of increasing ST. Children that increased and those that maintained high ST showed greater odds of presenting a Snacking DP at 7 years (OR = 2.34, 95%CI:1.64–3.35) and (OR = 2.65, 95%CI:1.89–3.72), respectively. No statistically significant differences were found regarding changes in ST and the child's BMI. Conclusion Children increasing screen exposure during this period were more frequently from lower socioeconomic strata and presented unhealthier DP.