The association between 24-hr movement patterns and self-harm incidence in adolescence

Area of Science:

• Public Health
• Adolescent Health
• Behavioral Science

Background:

• Self-harm is a critical public health concern among adolescents.
• Existing research on physical activity and youth self-harm is limited, often relying on self-reports and focusing on moderate-to-vigorous physical activity (MVPA).
• The role of light-intensity physical activity (LIPA) and objective 24-hour movement measures remains underexplored.

Purpose of the Study:

• To prospectively investigate the associations between accelerometer-measured 24-hour movements and subsequent self-harm in adolescents.
• To differentiate the impact of LIPA and MVPA on self-harm risk.
• To explore the relationship between sedentary behavior, sleep, and self-harm.

Main Methods:

• Prospective cohort study of 2,016 children from the UK Millennium Cohort Study (MCS4).
• Objective measurement of MVPA, LIPA, sedentary behavior (SB), and sleep using accelerometers at age 7.
• Assessment of self-harm behaviors via validated questionnaires at ages 14 and 17, analyzed with logistic and compositional models.

Main Results:

• A significant inverse association was found between LIPA and self-harm (OR 0.76), with a stronger effect in compositional models (OR 0.23).
• MVPA exhibited a non-linear, inverted U-shaped association with self-harm, with risk decreasing above 1.7 hours/day.
• Sedentary behavior and sleep were not significantly associated with self-harm.

Conclusions:

• Light-intensity physical activity (LIPA) is a key factor in reducing adolescent self-harm.
• Current findings support 24-hour movement guidelines that emphasize activity transitions.
• LIPA should be highlighted in early prevention strategies for adolescent self-harm.