Interaction effect of screen time and sugar-sweetened beverages with depressive symptoms in adolescents: evidence from a large sample-based survey in China.

Excessive screen time and the consumption of sugar-sweetened beverages are found to be independent predictors of depressive symptoms. However, the potential interaction effect of screen time and sugar-sweetened beverages, that is, whether one exposure factor strengthens the association of another with depressive symptoms, remains unclear. A large-scale adolescent health surveillance survey was conducted in 27 schools in eight regions across China. A total of 22,868 students were recruited to complete an eligible questionnaire to provide details of their screen time and sugar-sweetened beverage consumption. Depressive symptoms were assessed using the Patient Health Questionnaire (PHQ-9). Multiplicative and additive interaction models were performed to estimate the interaction effects of screen time and sugar-sweetened beverages on depressive symptoms, and whether the relationship varied by age group was also examined. The multivariate logistic regression model showed that even if the confounding factors were controlled, screen time and sugar-sweetened beverages were still risk factors for depressive symptoms in adolescents. Interaction models indicated that screen time and sugar-sweetened beverages in combination were related to greater odds of depressive symptoms. Compared with late adolescents, early adolescents had a higher probability of depressive symptoms when exposed to the joint effects. Our study may hopefully deepen the understanding of the association between screen time and sugar-sweetened beverages and depressive symptoms. Future research should further explore how and why screen time and sugar-sweetened beverages affect individuals more profoundly in early adolescence than in late adolescence and how to mitigate this.