Association between screen time and non-suicidal self-injury among adolescents: a compositional isotemporal substitution analysis.

Higher screen time was associated with an increased risk of non-suicidal self-injury among adolescents.

• Cross-sectional study of 6,311 adolescents in Hefei, China using self-administered questionnaires.
• Compositional logistic regression analysis was used, examining screen time relative to remaining behavioral components.
• The association between higher screen time and increased NSSI risk was statistically significant (p < 0.001).
• Screen time was analyzed as part of a 24-hour time-use composition including non-screen-based sedentary time, physical activity, and sleep time.

Higher non-screen-based sedentary time was associated with an increased risk of non-suicidal self-injury.

• Non-screen-based sedentary time (NSST) was one of four behavioral components in the compositional analysis.
• The association between higher NSST and increased NSSI risk was statistically significant (p < 0.001).
• This finding was derived from compositional logistic regression analysis relative to remaining behavioral components.
• Sample consisted of 6,311 adolescents in Hefei, China.

Higher light physical activity was associated with a reduced risk of non-suicidal self-injury.

• Compositional logistic regression revealed that light physical activity (LPA), relative to remaining behavioral components, was associated with reduced NSSI risk (p = 0.016).
• The Compositional Isotemporal Substitution Model (CISM) showed that substituting screen time with LPA was associated with a reduced risk of NSSI.
• Conversely, replacing LPA with screen time was linked to an elevated risk of NSSI.
• LPA was analyzed as part of a compositional 24-hour time-use dataset.

Higher sleep time was associated with a reduced risk of non-suicidal self-injury among adolescents.

• Compositional logistic regression analysis revealed that sleep time, relative to remaining behavioral components, was associated with reduced NSSI risk (p < 0.001).
• Sleep time was one of the four behavioral components examined in the 24-hour compositional time-use analysis.
• The study used the Compositional Isotemporal Substitution Model (CISM) to account for the interdependent, compositional nature of 24-hour time-use data.
• Data were collected from 6,311 adolescents in Hefei, China via self-administered questionnaires.

The Compositional Isotemporal Substitution Model demonstrated that replacing light physical activity with screen time was linked to elevated NSSI risk, while the reverse substitution was protective.

• CISM is described as 'a statistical method that estimates health effects of replacing time in one behavior with another while accounting for the interdependent, compositional nature of 24-h time-use data.'
• Replacing LPA with ST was associated with elevated NSSI risk in adolescents.
• Substituting ST with LPA was associated with a reduced risk of NSSI.
• The model examined four behavioral components: screen time, non-screen-based sedentary time, physical activity, and sleep time.

The global incidence of non-suicidal self-injury has risen in recent years, with adolescents being the main affected group.

• NSSI is described as posing 'a significant challenge in public health.'
• The study was motivated by this rising trend and conducted in Hefei, China with a sample of 6,311 adolescents.
• A cross-sectional design was used with data collected via self-administered questionnaires.