Digital technology use and muscle-building behaviors in young adults.

OBJECTIVE: Digital technology use and muscle-building behaviors reflect a wide range of behaviors with associated health risks. However, links between digital technology use and muscle-building behaviors remain unknown and this study aimed to address this gap. METHOD: Data were collected from a diverse sample of 1,483 young adults (mean age 22.2 ± 2.0 years) participating in the population-based Eating and Activity over Time 2018 study. Gender-stratified-modified Poisson regression models were used to determine cross-sectional associations between three types of digital technology use (screen time, social media, weight-related self-monitoring apps) and five types of muscle-building behaviors (changing eating, exercise, protein powders/shakes, pre-workout drinks, steroids/growth hormone/creatine/amino acids) in young adulthood, adjusted for sociodemographic characteristics and body mass index. RESULTS: Screen time and social media were either not found to be associated with muscle-building behaviors or in a few instances, associated with less use of these behaviors (e.g., screen time and pre-workout drinks in men). In contrast, the use of weight-related self-monitoring apps was positively associated with all muscle-building behaviors, including steroids/growth hormone/creatine/amino acids in men (prevalence ratio [PR] = 1.83; 95% confidence interval [CI]: 1.13-2.97) and women (PR = 4.43; 95% CI: 1.68-11.68). DISCUSSION: While most recreational screen time may represent sedentary behaviors not related to muscle-building behaviors, weight-related self-monitoring apps are highly associated with more muscle-building behaviors and could be a future target for interventions to discourage the use of steroids and other harmful muscle-building substances.