The public health challenges of children's and adolescents' digital media use: applying the digital determinants of health as an interpretive framework.

Children and adolescents are growing up in a hybrid world in which digital media has become part of the infrastructure of everyday life and a structural determinant of their health. In the second paper of this Series on the digital determinants of health, we apply the framework introduced in the first paper to one of the most contested questions in public health: how young people's digital media use shapes their health and wellbeing. Using the digital determinants of health framework to interpret the current evidence base, we examine what is known, and what remains poorly understood, about the public health implications of children's and adolescents' digital media use. Evidence suggests that digital media use can be associated with both benefits and harms although it is more consistently associated with adverse mental, behavioural, physical, cognitive, and social outcomes, with developmental stage emerging as an important moderator. Illustrative modelling indicates the potential population burden is substantial, even as its causal basis remains uncertain. Research to date has privileged easily measured proxies, such as screen time, and given insufficient attention to the platform design, algorithmic systems, and commercial incentives that shape young people's experiences. Situating young people's digital media use with a digital determinants of health framework, we conclude that protecting children's and adolescents' health calls for a precautionary, structural response-one that moves beyond individual behaviour change to reshape the digital systems, incentives, and knowledge practices that determine how digital media affects health.