Dietary patterns and smartphone use in adolescents in Korea: A nationally representative cross-sectional study.

BACKGROUND AND OBJECTIVES Diet and smartphone use are daily routines that can affect adolescents' mental health. This study investigated whether the frequency of the consumption of certain foods is associated with the duration of smartphone use and problems caused by smartphone overuse in adolescents. METHODS AND STUDY DESIGN Food consumption and smartphone use were investigated in 62,276 Korean adolescents aged 12-18 years by using a nationwide self-report survey. Food intake was assessed on a seven-point scale ("never" to "1, 2, and 3 or more times per day") for nine items: fruits, vegetables, milk, soda, energy drinks, sweetened beverages, fast food, instant noodles, and snacks. The durations of smartphone use and problematic use were determined using self-report items. RESULTS Most respondents (66.5%) used smartphones over 2 hours per day. Higher consumption levels of fruits (F=151.8; p<0.001), vegetables (F=119.9; p<0.001), and milk (F=33.0; p<0.001) were associated with significantly lower smartphone usage, whereas higher consumption levels of soda (F=292.5; p<0.001), energy drinks (F=24.0; p<0.001), sweetened beverages (F=224.8; p<0.001), fast food (F=192.1; p<0.001), instant noodles (F=196.2; p<0.001), and snacks (F=131.6; p<0.001) were positively associated with higher smartphone usage. CONCLUSIONS Our findings provide useful clinical information regarding the association between dietary habits and smartphone use in adolescents. Future studies should investigate underlying mechanisms and examine the efficacy of dietary interventions for adolescents with excessive smartphone use.