Association between age of first exposure and heavy internet use in a representative sample of 317,443 adolescents from 52 countries.

Internet usage among adolescents has increased substantially over the last years, concurrently with emerging concerns that an abusive use is associated with detrimental health outcomes. Our objective was to examine the association between age of first exposure and heavy Internet usage in different domains. Data from the 2018 wave of the Programme for International Student Assessment (PISA) were retrieved. This included a total of 317,443 participants (49.2% boys) aged 15 and 16 years from 52 countries. Data from both Internet use and age of first exposure were retrieved and used to conduct metanalyses with random effects. Adolescents reporting an age of first exposure of Internet usage at ≥ 13 years old had the lowest odds for heavy Internet use (> 2 h/day) (reference group: ≤ 9 years) during weekends (odds ratio, 0.41 [95% CI, 0.35-0.48]), weekdays (odds ratio, 0.45 [95% CI, 0.37-0.56]), and during school time (odds ratio (odds ratio, 0.86 [95% CI, 0.77-0.96]) even when adjusted for sex, socioeconomic status, and country. A stronger association was observed in adolescents from South and Central America and Eastern Mediterranean regions in the domain of weekends and weekdays. The results indicate that early internet exposure is associated with heavy Internet use, particularly during weekends and weekdays, regardless the geographical region, in a linear fashion. Further research should aim to examine if better education and parental control in specific areas may avoid excessive Internet use that possibly have a negative influence on both mental and physical health.