Use of screens and intake of unhealthy food among children and adolescents: association with physical activity in a cross-sectional study

BACKGROUND: The intake of unhealthy food taken on very regular basis may bring even further negative impact on health if associated with excessive time using of screen-based electronic devices. OBJECTIVE: To estimate the association between the use of different types of screen-based devices and the intake of unhealthy foods amongst children and adolescents and to determine whether daily physical activity (DPA) has a moderating effect on the association. METHODS: Cross-sectional study carried out with a probabilistic sample of students from second to fifth grade of public elementary schools in Feira de Santana, Bahia (n = 2,477; girls: 53.2%; age: 9.1 ± 1.38 years; BMI z-score 0.37 ± 4.19 Kg/m²). Food intake, screen use, and physical activity were assessed using an online questionnaire based on previous day recall (Web-CAAFE). Prevalence Ratios (PR) and 95% Confidence Intervals (95%CI) were estimated via multiple zero-inflated negative binomial regression, with adjustments for sex, age, and weekly frequency of school meal intake. The moderating effect of DPA was verified by inserting interaction terms with each screen-based device individually and with the daily sum of screen-based device exposure (∑ Screens). RESULTS: The majority of students (72.2%) reported using screens. The intake of unhealthy foods was positively associated with the use of cell phones (PR = 1.21; 95%CI = 1.13–1.30), computers (PR = 1.33; 95%CI = 1.22–1.46), and video games (PR = 1.36; 95%CI = 1.22–1.52). TV use was inversely associated with intake of unhealthy foods (PR = 0.92; 95%CI = 0.87–0.99). DPA moderated the effect of video game use on intake of unhealthy foods, that is, among students with DPA ≥ 4 who used video games, the intake of unhealthy foods was 21% lower (PR = 0.79; 95%CI = 0. 65-0.97). Overall, ∑ Screen-based devices were associated with a 20% increase in intake of unhealthy foods. CONCLUSION: The intake of unhealthy foods was positively associated with the use of cell phones, computers, and video games. In addition, a frequency of four or more DPA attenuated the effect of video game exposure on intake of unhealthy foods. Upcoming investigations on the use of screen-based devices and the intake of unhealthy foods among schoolchildren should consider the exposure to different types of screen-based devices, as well as the influence of DPA. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40795-023-00763-4.