JMIR Publications

ABSTRACT

Background:

Use of digital technology such as mobile phones is ubiquitous in adolescents. However, excessive usage may have adverse health effects.

Objective:

We aimed to assess the social predictors of digital technology use and their association with body weight outcomes in a large cohort of adolescents.

Methods:

We used baseline data from a subset of a large adolescent cohort of 39 schools across Greater London who participated in the Study of Cognition, Adolescents and Mobile Phones (n=1,473). Digital technology use included phone calls, internet use on mobile phones, and video gaming on any device. Multi-level regression was used to assess the associations between digital technology use and age- and sex-specific body mass index (BMI) z-score and overweight (including obesity) derived from measured height and weight. We examined whether the associations were mediated by insufficient sleep.

Results:

Generally, participants with lower socioeconomic status reported more use of digital technology. Internet use on mobile phones for more than 3 h per day was associated with higher BMI z-score (adjusted β=0.30, 95% confidence interval (95% CI) 0.11, 0.48) and greater odds of being overweight (adjusted odds ratio=1.60, 95% CI 1.09, 2.34), compared with low use (≤30 min). Similar associations between video gaming and body weight were found. BMI z-score was more strongly related to weekday digital technology use (internet use on mobile phones and video gaming) than weekend use. Insufficient sleep partly mediated the associations between weekday digital technology use and BMI z-score (proportion of mediation from 9.0% to 16.2%) by an indirect effect.

Conclusions:

We found an association between digital technology use and body weight in adolescents, partly mediated by insufficient sleep, suggesting underlying mechanisms may be multi-factorial. Further research with longitudinal data is essential to explore the direction of relationships.