Sociodemographic Associations With Early Smartphone Ownership in US Adolescents

Smartphones are a normative part of adolescent daily life. Most youth enter smartphone ownership between ages 10 and 12 years in the US,1 yet there is variability across individuals. There are benefits and risks associated with early smartphone ownership and use. Although smartphones offer social opportunities, they can also detract from the quality of in-person interactions.2 Further, smartphones can expose youth to inappropriate content and cyberbullying, can interfere with sleep, and may negatively impact mental health and impulsivity.3 Given recent legislation regarding a minimum age for social media use, it is of interest to understand the sociodemographic factors related to the age of smartphone ownership. This study leverages a large national dataset to examine sociodemographic predictors of first smartphone ownership age in adolescent youth.The ongoing ABCD Study collected demographic and screen use data (among other domains) from 11 878 children and primary caregivers at baseline (mean age = 9.9 years) beginning in 2016 with annual follow-up assessments.4 The analytic sample included all participants with complete data (N = 9475). Parents reported sociodemographic information at baseline. Parents were asked each year at what age their child received their first smartphone.4 Mplus version 8.3 was used for analyses.5 Descriptive statistics compared sociodemographic characteristics across smartphone ownership timing. We then estimated a cross-sectional multivariable logistic regression model to examine associations between key sociodemographic predictors (sex, race/ethnicity, household income, household structure, and parental education)6 and first smartphone ownership age. Race/ethnicity variables were included because the purpose of this study was to identify disparities by sociodemographic factors, and prior studies show variability in technology use patterns in youth based on this social construct.7 Self-reported categories were based on survey responses. We assessed multicollinearity via variance inflation factors (VIF > 5). Early smartphone ownership (