BACKGROUND: Long screen time hours may be associated with behavioral problems in children. To better understand the relationship between children's behavioral problems and screen time, it the associated risk factors must be subdivided based on the purpose underlying screen use. This study examined the relationship between screen time based on intended usage and behavioral problems in Japan. METHODS: This study included 3,332 children aged between 7-17 years from the Hokkaido Study on Environment and Children's Health. From October 2020 to October 2021, the children and their parents answered questionnaires on the children's screen use duration (never used, <30 min, ≥30 min & <1 hour, ≥1 h & <2 h, ≥2 h) based on seven intended usage categories: watching television/video, video gaming, reading books/comics, sending/receiving e-mail/messages, browsing/posting on social networking services, studying for classes/homework, drawing/editing pictures/photos/videos, along with the Strengths and Difficulties Questionnaire (SDQ). Logistic regression was used to analyze the association between screen time, purpose of children's screen use, and behavioral problems across the 13 SDQ total scores. RESULTS: The mean ± standard deviation age of the participants was 12.4 ± 2.4-years-old, 487 (14.6%) children were determined to have behavioral problems, and the duration of screen time increased with their age. The children's primary purposes for screen use were watching television/video, video gaming, sending/receiving e-mail/messages, and browsing/posting on social networking services. Children who reported playing video games for ≥2 hours on weekdays had higher odds of problematic total difficulties scores than never user (Odds Ratio: 2.10, 95% confidence interval: 1.45-3.06). CONCLUSION Long video gaming screen time is associated with behavioral issues, hyperactivity/inattention, and prosocial behaviors in children. Conversely, watching television and videos for 30 min-1 h per day, using e-mail or messaging, and using social networking services were significantly association with reduced odds ratio for peer relationship problems as compared to children who never engaged in these activities. Longitudinal follow-up is needed to further examine screen time and problem behaviors.
Humans ; Screen Time ; Child ; Japan/epidemiology* ; Male ; Female ; Adolescent ; Problem Behavior/psychology* ; Surveys and Questionnaires ; Child Behavior ; Television/statistics & numerical data* ; Video Games/statistics & numerical data*

Vibration sensation is related to motor function. However, it is unclear which vibration frequencies are associated with motor function. Therefore, in this cross-sectional study, we investigated whether a specific frequency of vibration sensation could explain motor functions. Thirty-two community-dwelling Japanese healthy older adults aged 70 years or older participated in the present study. Grip strength, one-leg standing time, and 10-m walking time were evaluated as indicators of motor function. Vibratory (40, 128, and 256 Hz) and tactile sensory tests were examined as sensory functions. Grip strength per body weight was significantly correlated with sex, body mass index, falls efficacy scale, vibration sensation with 40 and 128 Hz, and 10-m walking time (P < 0.05). Furthermore, one-leg standing time showed a correlation between vibration sensation (128 and 256 Hz) and fall history (P < 0.05). However, 10-m walking time was significantly correlated with only the grip strength to body weight ratio. Multiple regression analysis showed that vibration sensation with 128 Hz (β = 0.427) and sex (β = -0.335) (P < 0.05) were significant independent variables associated with grip strength to body weight ratio. Vibration sensation with 256 Hz (β = 0.465) and age (β = -0.343) (P < 0.05) were significant independent variable associated with one-leg standing time. No significant variables were identified for the 10-m walking time. Vibration sensation associated with motor function shows specific frequency characteristics in community-dwelling older Japanese adults.