Physical Activity Among Preadolescents Modifies the Long-Term Association Between Sedentary Time Spent Using Digital Media and the Increased Risk of Being Overweight.

BACKGROUND: This study aimed to examine whether sedentary digital media use in preadolescence increases the risk of being overweight 3 years later, and whether this association differs based on preadolescents' leisure-time physical activity (LTPA) levels. METHODS: The authors conducted a 3-year follow-up study among 4661 participants with a mean (SD) age of 11 (1) years at baseline and 14 (1) years at follow-up. A web-based questionnaire assessed sedentary digital media use and LTPA. The authors categorized baseline LTPA duration into 3 levels: 0 to 5 (low), 6 to 8 (moderate), and ≥9 (high) hours per week. In addition, the authors categorized adolescents as normal weight or overweight/obese at follow-up. RESULTS: Greater amounts of sedentary digital media use at baseline associated with an increased risk of being overweight 3 years later even after adjusting for confounders. This only held for preadolescents with low baseline LTPA (OR = 1.14; 95% confidence interval, 1.05-1.24), but not among those with moderate (OR = 1.02; 0.91-1.15) or high (OR = 0.96; 0.85-1.08) LTPA. CONCLUSIONS: Preadolescent LTPA modified the long-term association between sedentary digital media use and being overweight; specifically, 6 hours per week or more of LTPA mitigated the increased risk of being overweight associated with higher amounts of digital media use.