摘要:BACKGROUND :Little is known about pathological Internet use (PIU) and online risky behaviors among elementary school children. We aimed to investigate the prevalence and factors associated with PIU and online risky behaviors. METHODS :A school-based cross-sectional study was conducted in Toyama, Japan in 2018. The study included 13,413 children in the 4th-6th grades (mean, 10.5 years old) from 110 elementary schools (61.1% of elementary schools in Toyama). We assessed PIU by Young's Diagnostic Questionnaire (YDQ) and risky behaviors. Poisson regression analysis was conducted. RESULTS :Totally, 13,092 children returned questionnaires (response rate 97.6%). The prevalence of PIU was 4.2% and that of each risky behavior was as follows: 21.6% in spending money online, 6.6% in uploading personal movies, 5.2% in interpersonal issues, and 2.4% in having met strangers. PIU was significantly associated with boys (prevalence ratio, PR=1.26; 95% confidence interval, CI: 1.04-1.52), skipping breakfast (PR=1.43; 95% CI: 1.14-1.79), Internet time (for 2~3h; PR=3.49, 95% CI: 2.63-4.65, for 3~4h; PR=4.45, 95% CI: 3.27-6.06, and for ≥4h; PR=8.25, 95% CI: 6.45-10.55), physical inactivity (PR=2.63; 95% CI: 2.00-3.47), late bedtime (PR=1.86; 95% CI: 1.45-2.39 for ≥11p.m.), no rules at home (PR=1.22; 95% CI: 1.01-1.46), no child-parent interaction (PR=1.37; 95% CI: 1.06-1.77), no close friends in real life (PR=1.69; 95% CI: 1.30-2.19). CONCLUSIONS :PIU and risky behaviors were not rare among the elementary school children. Besides unhealthy lifestyles, social and family environments were associated with PIU. Having child-parent interaction and helping children develop close friendships in real life are effective deterrents to PIU.